Method for preparing isocyanate and device

Abstract

The present application provides a method for purifying an amine salt (e.g., pentanediamine carbonate). According to the method, the amine salt (e.g., pentanediamine carbonate) is heated, flash-evaporated, and sublimed to obtain a purified gaseous amine salt (e.g., pentanediamine carbonate) which is directly used for further preparation of isocyanate (e.g., pentamethylenediisocyanate), and there is no need to use an alkaline substance to treat the amine salt to form a free-state amine for further preparation of isocyanate (e.g., pentamethylenediisocyanate). The present application further provides a method for preparing isocyanate (e.g., pentamethylenediisocyanate) from an amine salt (e.g., a pentanediamine salt) and phosgene. The present application further provides a device for implementing the method of the present application.

Description

Method and device for preparing isocyanate Technical Field

[0001] This application belongs to the field of chemical engineering, and specifically relates to methods for purifying amine salts (e.g., pentamethylenediamine carbonate) and methods for preparing isocyanates, as well as apparatus for implementing the methods. This application also relates to a pentamethylenediamine derivative, a method for purifying the pentamethylenediamine derivative, and a method for preparing pentamethylenediisocyanate by a gas phase process using the pentamethylenediamine derivative provided herein and phosgene, as well as apparatus for implementing the methods. Background Art

[0002] Isocyanates are a class of compounds containing one or more isocyanate groups. They include aliphatic isocyanates, aromatic isocyanates, unsaturated isocyanates, halogenated isocyanates, thioisocyanates, phosphorus-containing isocyanates, inorganic isocyanates, and blocked isocyanates. Due to their highly unsaturated isocyanate groups, they possess high chemical activity and can undergo significant chemical reactions with a variety of substances. Consequently, they are widely used in polyurethanes, polyurethaneureas, polyureas, polymer modification, organic synthesis reagents, agriculture, medicine, and other fields.

[0003] The principle of preparing isocyanates by reacting amines with phosgene is well known in the art. For example, pentamethylenediamine (PDA) or its salts react with phosgene to produce pentamethylene diisocyanate (PDI). PDA produced by fermentation is generally a PDA salt, such as PDA hydrochloride, PDA carbonate, or PDA sulfate, and typically requires purification before reaction with phosgene. Commonly used methods for purifying PDA salts are as follows: (1) adding an alkaline substance to a PDA salt solution to form a free PDA solution, and then distilling to obtain PDA (see, for example, CN107043332B), but this process still needs to be improved in terms of handling by-product salts and energy consumption; (2) adding an alkaline substance to a PDA salt solution to form a free PDA solution, using a cationic resin to adsorb PDA, and then eluting the PDA adsorbed on the cationic resin (see, for example, CN108276292B), but this process is inefficient and has high resin maintenance costs; (3) adding an alkaline substance to a PDA salt solution to form a free PDA solution, and then using an extractant to extract the PDA in the solution, but this process has high operating costs and a greater impact on the surrounding environment.

[0004] Therefore, there is still a need for optimized amine salt purification methods, new pentamethylenediamine derivatives, optimized pentamethylenediamine derivative purification methods and isocyanate preparation methods.

[0005] Summary of the Invention

[0006] One of the objectives of the present application is to provide a method for purifying an amine salt (e.g., pentamethylenediamine carbonate) by flash-subliming the amine salt (e.g., pentamethylenediamine carbonate) through heating to obtain a purified gaseous amine salt (e.g., pentamethylenediamine carbonate), which is then directly used in the next step of preparing an isocyanate (e.g., pentamethylenediisocyanate). This method eliminates the need to treat the amine salt with an alkaline substance to convert it into a free amine for use in the next step of preparing an isocyanate (e.g., pentamethylenediisocyanate). Another objective of the present application is to provide a method for preparing an isocyanate (e.g., pentamethylenediamine carbonate) from an amine salt (e.g., pentamethylenediamine carbonate) and phosgene. Another objective of the present application is to provide an apparatus for implementing the method of the present application.

[0007] In one aspect, the present application provides a method for purifying an amine salt, wherein the method comprises heating a first mixture comprising an amine salt to the sublimation temperature of the amine salt to obtain a gaseous amine salt. In certain embodiments, the heating temperature is controlled to be a temperature at which the amine salt sublimes but does not decompose. In certain embodiments, the heating temperature is 70 to 140° C. (e.g., 70 to 130° C.). In certain embodiments, the method for purifying an amine salt provided herein further comprises desubliming the obtained gaseous amine salt. In certain embodiments, the obtained gaseous amine salt is desublimed at 30 to 50° C.

[0008] In another aspect, the present application provides a method for purifying an amine salt, wherein the method comprises:

[0009] (1) mixing a first mixture containing an amine salt with a carrier gas to obtain a second mixture;

[0010] (2) preheating the second mixture obtained in step (1) in a heater so that the outlet temperature of the heater is close to or equal to the sublimation temperature of the amine salt; and

[0011] (3) Separating the amine salt preheated in step (2) at the sublimation temperature of the amine salt.

[0012] In certain embodiments, at least a portion of the carrier gas in step (1) comes from by-product gas of the reaction system.

[0013] In some embodiments, the carrier gas described in step (1) is compressed to 0.2-0.6 MPa and passed into a powder absorber, thereby forming a negative pressure zone in the powder absorber. In some embodiments, the powder absorber is a Venturi type. In some embodiments, the first mixture described in step (1) is mixed with the carrier gas in the negative pressure zone of the powder absorber to obtain the second mixture.

[0014] In some embodiments, the flow rate of the carrier gas is 0.1 to 1 m 3 / h.

[0015] In certain embodiments, the first mixture in step (1) is in powder form.

[0016] In some embodiments, the first mixture described in step (1) flows into the powder absorber under the action of gravity through a rotary feeding valve. In some embodiments, the delivery amount of the first mixture to the powder absorber is controlled by the rotary feeding valve. In some embodiments, the delivery amount of the first mixture to the powder absorber is controlled at 1 to 5 kg / h by the rotary feeding valve. In some embodiments, the rotary feeding valve is connected to the powder absorber by a delivery pipe. In some embodiments, the inner diameter of the delivery pipe is 1 to 10 mm.

[0017] In some embodiments, the mixing in step (1) is performed at room temperature. In some embodiments, the room temperature is in the range of -10°C to 40°C.

[0018] In certain embodiments, in step (2), the heating temperature is controlled so that the outlet temperature of the heater is a temperature at which the amine salt sublimes but does not decompose. In certain embodiments, in step (2), the second mixture obtained in step (1) is heated to 70-140° C. (e.g., 70-130° C.).

[0019] In some embodiments, the heating in step (2) is performed in a heater having a heating medium. In some embodiments, the heating medium is thermal oil. In some embodiments, the outer surface of the inner tube of the heater is coated with a thermally conductive metal.

[0020] In some embodiments, step (3) comprises flash-subliming the preheated amine salt obtained in step (2) in a separator to form a gaseous amine salt. In some embodiments, step (3) comprises subjecting the preheated amine salt obtained in step (2) to a swirling motion along a draft tube in the separator, so that at least a portion of the gaseous amine salt is separated from the solid impurities. In some embodiments, the gaseous amine salt is discharged through an exhaust port at the upper end of the separator, and the solid impurities are discharged from a discharge port at the lower end of the separator.

[0021] In certain embodiments, the method does not include the step of alkalizing the first mixture comprising the amine salt using an alkaline substance. In certain embodiments, the alkaline substance is selected from the group consisting of sodium hydroxide, potassium hydroxide, aqueous ammonia, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, and any combination thereof.

[0022] In certain embodiments, the amine salt is of the formula R(NH2) nIn certain embodiments, n is 2 and R is an aliphatic or aromatic hydrocarbon group. In certain embodiments, n is 2 and R is an aliphatic hydrocarbon group. In certain embodiments, n is 2 and R is an aliphatic hydrocarbon group having 2 to 10 carbon atoms. In certain embodiments, n is 2 and R is a linear or cyclic aliphatic hydrocarbon group having 3 to 10 carbon atoms.

[0023] In certain embodiments, the amine salt is selected from the group consisting of hydrochloride, sulfate, bisulfate, nitrate, and carbonate.

[0024] In certain embodiments, the amine salt is selected from one or more of the following groups: ethylamine salt, butylamine salt, pentamethylenediamine salt, hexamethylenediamine salt, 1,4-diaminobutane salt, 1,8-diaminooctane salt, aniline salt, p-phenylenediamine salt, m-phenylenediamine salt, toluenediamine salt, 1,5-naphthalenediamine salt, diphenylmethanediamine salt, dicyclohexylmethanediamine salt, m-cyclohexyldimethylenediamine salt, isophoronediamine salt, methylcyclohexanediamine salt, and trans-1,4-cyclohexanediamine salt.

[0025] In certain embodiments, the amine salt is selected from the group consisting of pentamethylenediamine carbonate, hexamethylenediamine carbonate, isophoronediamine carbonate, and methylcyclohexanediamine carbonate. In certain embodiments, the amine salt is pentamethylenediamine carbonate. In certain embodiments, the amine salt is 1,5-pentamethylenediamine carbonate. In certain embodiments, the amine salt is pentamethylenediamine carbonate, and the carrier gas is carbon dioxide.

[0026] In certain embodiments, the first mixture comprising an amine salt is prepared by introducing carbon dioxide into lysine to form lysine carbonate (bicarbonate), and then reacting the lysine carbonate (bicarbonate) with lysine decarboxylase to generate pentamethylenediamine carbonate.

[0027] In another aspect, the present application provides a method for preparing isocyanate, wherein the method comprises:

[0028] (a) providing an amine salt stream and a phosgene stream and mixing them in a material mixing device;

[0029] (b) spraying the mixture obtained in step (a) into the diffusion port of the reactor, and using a baffle disposed in the reactor near the feed end to resist the lateral velocity of the material at the discharge end of the material mixing device;

[0030] (c) The amine salt and phosgene in the mixture enter the reaction zone of the reactor and react in the reaction zone to generate isocyanate.

[0031] In certain embodiments, the method for preparing isocyanate described herein further comprises the following steps:

[0032] (d) collecting the isocyanate prepared in step (c).

[0033] In certain embodiments, the amine salt stream in step (a) is purified according to the amine salt purification method described herein.

[0034] In certain embodiments, the amine salt stream in step (a) is in a solid state, and the phosgene stream is in a gaseous state.

[0035] In certain embodiments, the amine salt is pentamethylenediamine carbonate, and the isocyanate is pentamethylene diisocyanate.

[0036] In certain embodiments, no solvent is used in step (a).

[0037] In another aspect, the present application provides an apparatus for purifying amine salts according to the method described in the present application, characterized in that the apparatus comprises a raw material storage tank, a powder absorber, a heater, and a separator, wherein:

[0038] The raw material storage tank is used to store the first mixture containing amine salt, and a first discharge port is provided at the bottom of the raw material storage tank;

[0039] The powder absorber is provided with a first air inlet, a first feed port, and a second discharge port. The first feed port is selectively connected to the first discharge port of the raw material storage tank through a valve, and is selectively connected to the first air inlet and the second discharge port, and negative pressure is formed in the powder absorber; the first air inlet is used to introduce carrier gas into the powder absorber;

[0040] The heater is provided with a second feed port and a third discharge port, and the second feed port is selectively connected to the second discharge port of the powder absorber;

[0041] The separator is provided with a guide tube, a first exhaust port and a fourth discharge port, wherein the guide tube is spirally arranged along the inner wall of the separator; the first exhaust port is arranged at the top of the separator for discharging gaseous amine salts; the fourth discharge port is arranged at the bottom of the separator for discharging solid impurities.

[0042] In certain embodiments, the valve is a rotary feed valve.

[0043] In certain embodiments, the heater contains a heating medium, and / or the outer surface of the inner tube of the heater is coated with a heat-conducting metal.

[0044] In certain embodiments, the separator is provided with a heating device.

[0045] In certain embodiments, the heating device of the separator includes a heating jacket disposed on an outer wall of the separator and / or a heating cylinder disposed inside the separator.

[0046] In another aspect, the present application also provides an apparatus for preparing isocyanate, wherein the apparatus is used to perform the method for preparing isocyanate described in the present application.

[0047] In another aspect, the present application provides a pentamethylenediamine derivative having a chemical formula of H2N(CH2)5NH2CO2, wherein the N atom and the C atom are connected by a covalent bond.

[0048] In certain embodiments, the chemical formula of the pentamethylenediamine derivative provided herein is in, Atoms and Atoms are connected by covalent bonds.

[0049] In certain embodiments, the pentamethylenediamine derivatives provided herein have an amide ester In certain embodiments, the pentamethylenediamine derivatives provided herein have the chemical structure shown below: and / or In certain embodiments, the pentamethylenediamine derivatives provided herein exist in the form of a mixture. In certain embodiments, the pentamethylenediamine derivatives provided herein comprise the following structure: In certain embodiments, in the pentamethylenediamine derivatives provided herein, The total molar amount of The molar amounts are essentially the same.

[0050] In certain embodiments, the pentamethylenediamine derivatives provided herein do not release carbon dioxide at temperatures above 70°C. In certain embodiments, the pentamethylenediamine derivatives provided herein do not release carbon dioxide at temperatures between 70°C and 140°C. In certain embodiments, the pentamethylenediamine derivatives provided herein have a sublimation temperature between 70°C and 140°C.

[0051] In certain embodiments, the chemical bond connection mode of the pentamethylenediamine derivative provided herein in deuterated water solvent and other deuterated solvents is different. In certain embodiments, the nuclear magnetic resonance analysis spectrum of the pentamethylenediamine derivative provided herein after being dissolved in the deuterated solvent CD3OD is shown in Figure 6. In certain embodiments, the pentamethylenediamine derivative provided herein after being dissolved in the deuterated water solvent (D2O) is shown in Figure 6. 1 H-NMR analysis and 13C-NMR analysis spectra are shown in Figures 7 and 8, respectively. In certain embodiments, the pentamethylenediamine derivatives provided herein are 1 H- 1 H COSY spectrum and 1 H- 13 The C COSY spectra are shown in Figures 9 and 10, respectively.

[0052] In certain embodiments, the pentamethylenediamine derivatives provided herein do not contain carbonate ions (CO3 2- ) or bicarbonate ion (HCO3 - ).

[0053] In another aspect, the present application provides a method for purifying a pentamethylenediamine derivative, wherein the method comprises heating a mixture comprising the pentamethylenediamine derivative described herein to a sublimation temperature of the pentamethylenediamine derivative to obtain a gaseous pentamethylenediamine derivative. In certain embodiments, the sublimation temperature of the pentamethylenediamine derivative is 70° C. to 140° C.

[0054] In certain embodiments, the methods for purifying pentamethylenediamine derivatives provided herein do not include the step of alkalizing the mixture comprising the pentamethylenediamine derivative with an alkaline substance. In certain embodiments, the alkaline substance is selected from the group consisting of sodium hydroxide, potassium hydroxide, aqueous ammonia, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, and any combination thereof.

[0055] In certain embodiments, the method for purifying pentamethylenediamine derivatives provided herein further comprises desubliming the obtained gaseous pentamethylenediamine derivatives. In certain embodiments, the desublimation treatment is performed at 30-50°C.

[0056] In certain embodiments, the mixture comprising pentamethylenediamine derivatives is prepared by the following method: introducing carbon dioxide into lysine to form lysine carbonate (bicarbonate), and then reacting the lysine carbonate (bicarbonate) with lysine decarboxylase to generate pentamethylenediamine derivatives.

[0057] In another aspect, the present application also provides a method for preparing pentamethylene diisocyanate, wherein the method comprises: using a pentamethylenediamine derivative as an amine feed stream and a phosgene feed stream to undergo a phosgenation reaction under gas phase conditions.

[0058] In certain embodiments, the present application provides a method for preparing pentamethylene diisocyanate, wherein the method comprises the following steps:

[0059] (a) providing a pentamethylenediamine derivative stream and a phosgene stream and mixing them in a material mixing device;

[0060] (b) spraying the mixture obtained in step (a) into the diffusion port of the reactor, and using a baffle disposed in the reactor near the feed end to resist the lateral velocity of the material at the discharge end of the material mixing device;

[0061] (c) The pentamethylenediamine derivative and phosgene in the mixture enter the reaction zone of the reactor and react in the reaction zone to generate pentamethylene diisocyanate.

[0062] In certain embodiments, the method for preparing pentamethylene diisocyanate provided herein further comprises step (d): collecting pentamethylene diisocyanate prepared in step (c).

[0063] In certain embodiments, in the methods for preparing pentamethylene diisocyanate provided herein, the pentamethylenediamine derivative stream in step (a) is purified according to the method for purifying pentamethylenediamine derivatives described herein. In certain embodiments, the pentamethylenediamine derivative stream in step (a) is solid, and the phosgene stream is gaseous. In certain embodiments, in the methods for preparing pentamethylene diisocyanate provided herein, no solvent is used in step (a).

[0064] In another aspect, the present application also provides an apparatus for preparing pentamethylene diisocyanate, wherein the apparatus is used to perform the method for preparing pentamethylene diisocyanate according to the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The above and other features of the present application will be more fully understood through the following description and the appended claims, taken in conjunction with the accompanying drawings. It should be understood that these drawings only depict several embodiments of the present application and, therefore, should not be construed as limiting the scope of the present application. By reference to the accompanying drawings, the present application will be more clearly and fully explained.

[0066] Figure 1 shows a schematic flow chart of a method for purifying amine salts according to one embodiment of the present application. In particular, 110 is a raw material storage tank; 111 is a first discharge port; 120 is a powder absorber; 121 is a first air inlet; 122 is a first feed port; 123 is a second discharge port; 130 is a heater; 131 is a second feed port; 132 is a third discharge port; 140 is a separator; 141 is a guide tube; 142 is a first exhaust port; 143 is a fourth discharge port; 144 is a heating jacket; 145 is a heating tube; and 150 is a valve.

[0067] Figure 2 shows a schematic flow chart of a method for preparing isocyanate according to one embodiment of the present application. In particular, 1 - solid storage tank; 2 - third feed port; 3 - third air inlet; 4 - solid conveying member; 5 - gas storage tank; 6 - second air inlet; 7 - gas compressor; 8 - gas flowmeter; 9 - material mixing device; 10 - reactor body; 11 - jacketed tube.

[0068] FIG3 shows a schematic structural diagram of a material mixing device used in a method for preparing isocyanate according to one embodiment of the present application, wherein 12 is an air inlet end.

[0069] FIG4 shows a schematic structural diagram of the injection inlet of a pipeline reactor used in a method for preparing isocyanate according to one embodiment of the present application, wherein 13 is a circular baffle; 14 is a fan-shaped feed end; and 15 is a fixing bar.

[0070] Figure 5 shows a top view of a pipeline reactor used in a method for preparing isocyanate according to one embodiment of the present application, wherein 10 is a reactor body; 11 is a jacketed tube; and 13 is an annular baffle.

[0071] FIG6 shows the NMR analysis spectrum of the PDA·CO2 covalent compound described in the present application after being dissolved in deuterated methanol (CD3OD).

[0072] FIG7 shows the PDA·CO2 covalent compound described in this application after being dissolved in deuterated water solvent (D2O). 1 H-NMR analysis spectrum.

[0073] FIG8 shows the PDA·CO2 covalent compound described in this application after being dissolved in deuterated water solvent (D2O). 13 C-NMR analysis spectrum.

[0074] FIG9 shows the PDA·CO2 covalent compound described in this application. 1 H- 1 H COSY spectrum.

[0075] FIG10 shows the PDA·CO2 covalent compound described in this application. 1 H- 13 C COSY spectrum. DETAILED DESCRIPTION

[0076] The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be employed, and other changes may be made, without departing from the spirit or scope of the subject matter of this application. It is understood that various configurations, substitutions, combinations, and designs of the various aspects of the present disclosure generally described herein and illustrated in the drawings may be made, all of which are expressly incorporated herein as a part of this disclosure.

[0077] Method for purifying amine salts

[0078] In one aspect, the present application provides a method for purifying an amine salt, wherein the method comprises heating a first mixture comprising an amine salt to a sublimation temperature of the amine salt to obtain a gaseous amine salt. In certain embodiments, the purity of the amine salt in the first mixture comprising the amine salt is 80% or more (e.g., 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, or 96% or more). In the actual industrial production process of preparing isocyanates by the phosgene method, the inventors found that it is necessary to ensure the high purity of the reactant amine salt (e.g., greater than 97%, greater than 98% or greater than 99%) in order to avoid pipe blockage in the actual production process. At normal temperature and pressure, amine salts usually exist in solid form. The inventors of the present application unexpectedly found that a high-purity gaseous amine salt can be obtained by heating a solid mixture comprising an amine salt to a certain temperature so that the amine salt sublimes. The purity of the gaseous amine salt obtained by this method can reach over 98%, thus meeting the needs of large-scale industrial production.

[0079] In some embodiments, the heating temperature is controlled to be a temperature at which the amine salt sublimes but does not decompose. Without being limited by any theory, it is preferred to control the heating temperature to a temperature at which the amine salt sublimes but does not decompose, because this setting can ensure that the purity of the gaseous amine salt obtained is sufficiently high and that the yield of the amine salt after purification is sufficiently high. In some embodiments, the heating temperature is 70 to 140°C (e.g., 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C or any specific temperature between any two numerical ranges above). In some embodiments, the heating temperature is 70 to 130°C.

[0080] In certain embodiments, the amine salt is a pentamethylenediamine derivative. In certain embodiments, the gaseous amine salt is a pentamethylenediamine derivative. For a detailed description of "pentamethylenediamine derivatives," please refer to the section entitled "Pentamethylenediamine Derivatives" in this application, and all descriptions of pentamethylenediamine derivatives therein apply to the description of amine salts in this section.

[0081] In some embodiments, the chemical formula of the amine salt is H2N(CH2)5NH2CO2, wherein the N atom and the C atom are connected by a covalent bond. In some embodiments, the chemical formula of the amine salt is in, Atoms and Atoms are connected by covalent bonds.

[0082] In certain embodiments, the amine salt has an amide ester In certain embodiments, the amine salt has the chemical structure shown below: and / or In certain embodiments, the amine salt exists in the form of a mixture. In certain embodiments, the amine salt comprises the following structure: In certain embodiments, the amine salt is The total molar amount of The molar amounts are essentially the same.

[0083] In certain embodiments, the amine salt comprises the following structure: In certain embodiments, the amine salt is composition.

[0084] In certain embodiments, the amine salt comprises in The total molar amount of The molar amounts are essentially the same.

[0085] In some embodiments, the chemical bond connection mode of the amine salt in deuterated water solvent and other deuterated solvents is different. In some embodiments, the nuclear magnetic resonance analysis spectrum of the amine salt after dissolving in the deuterated solvent CD3OD is shown in Figure 6. In some embodiments, the chemical bond connection mode of the amine salt in deuterated water solvent (D2O) is different. 1 H-NMR analysis and 13 C-NMR analysis spectra are shown in Figures 7 and 8, respectively. In certain embodiments, the amine salt 1 H- 1 HCOSY spectrum and 1 H-13 The C COSY spectra are shown in Figures 9 and 10, respectively.

[0086] In certain embodiments, the amine salt does not contain carbonate ions (CO3 2- ) or bicarbonate ion (HCO3 - ).

[0087] In certain embodiments, the method for purifying an amine salt provided herein further comprises desublimating the obtained gaseous amine salt. Without being bound by any theory, it is believed that the lower the desublimation temperature, the more favorable the desublimation of the gaseous amine salt. In certain embodiments, the obtained gaseous amine salt is desublimated at 30 to 50° C. (e.g., 30° C., 31° C., 32° C., 33° C., 34° C., 35° C., 36° C., 37° C., 38° C., 39° C., 40° C., 41° C., 42° C., 43° C., 44° C., 45° C., 46° C., 47° C., 48° C., 49° C., 50° C., or any specific temperature between any two numerical ranges above).

[0088] In another aspect, the present application provides a method for purifying an amine salt, wherein the method comprises:

[0089] (1) mixing a first mixture containing an amine salt with a carrier gas to obtain a second mixture;

[0090] (2) preheating the second mixture obtained in step (1) in a heater so that the outlet temperature of the heater is close to or equal to the sublimation temperature of the amine salt; and

[0091] (3) Separating the amine salt preheated in step (2) at the sublimation temperature of the amine salt.

[0092] The following describes in detail the steps (1), (2) and (3) of the method for purifying amine salts described in the present application.

[0093] Step (1)

[0094] In the method for purifying amine salt provided in the present application, step (1) comprises mixing a first mixture containing amine salt with a carrier gas to obtain a second mixture.

[0095] 1. A first mixture comprising an amine salt

[0096] In this application, "amine salt" refers to a salt formed by a compound containing an amino (-NH2) group (i.e., an amine) as a starting material for preparing isocyanate and an inorganic acid or an organic acid, including an amine derivative (e.g., a pentamethylenediamine derivative), wherein the derivative does not contain an ionic bond, for example, the atoms of the derivative are connected by covalent bonds. For example, in some embodiments, the amine salt is a compound having the structural formula R(NH2)n In some embodiments, n is 2 and R is an aliphatic or aromatic hydrocarbon group. In some embodiments, n is 2 and R is an aliphatic hydrocarbon group. In some embodiments, n is 2 and R is an aliphatic hydrocarbon group having 2 to 10 carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10 carbon atoms). In some embodiments, n is 2 and R is a straight chain or cyclic aliphatic hydrocarbon group having 3 to 10 carbon atoms (e.g., 3, 4, 5, 6, 7, 8, 9, 10 carbon atoms). In some embodiments, n is 2 and R is an alicyclic hydrocarbon group having 3 to 10 carbon atoms (e.g., 3, 4, 5, 6, 7, 8, 9, 10 carbon atoms). In certain embodiments, n is 2, and R is an aromatic hydrocarbon group having 4-10 carbon atoms (e.g., 4, 5, 6, 7, 8, 9, 10 carbon atoms). In this application, "hydrocarbon group" should be understood as "alkylene group" if it is needed as a linking group. In this application, the term "aromatic hydrocarbon group" refers to monocyclic and polycyclic ring systems having a total of 5 to 12 ring members, wherein at least one ring in the system is aromatic. "Aromatic hydrocarbon group" in this application also includes heteroaromatic hydrocarbon groups with heteroatoms (e.g., nitrogen atoms, oxygen atoms, sulfur atoms, etc.) on the ring.

[0097] In certain embodiments, the amine used to form the amine salt is a primary amine, i.e., contains an NH2 group. In certain embodiments, the amine used to form the amine salt is a diamine, i.e., contains two NH2 groups. In certain embodiments, the amine used to form the amine salt is selected from one or more of the following groups: ethylamine, butylamine, pentamethylenediamine (PDA), hexamethylenediamine (HDA), 1,4-diaminobutane, 1,8-diaminooctane, aniline, p-phenylenediamine, m-phenylenediamine, toluenediamine, 1,5-naphthalenediamine, diphenylmethanediamine, dicyclohexylmethanediamine, m-cyclohexyldimethylenediamine, isophoronediamine (IPDA), methylcyclohexanediamine (HTDA), trans-1,4-cyclohexanediamine. In certain embodiments, the amine used to form the amine salt is selected from one or more of the following groups: pentamethylenediamine (e.g., 1,5-pentanediamine), hexamethylenediamine (e.g., 1,6-hexamethylenediamine), p-phenylenediamine, isophoronediamine, methylcyclohexanediamine, and toluenediamine.

[0098] In certain embodiments, the amine salt is selected from the group consisting of hydrochloride, sulfate, bisulfate, nitrate, and carbonate. In certain embodiments, the amine salt is selected from one or more of the group consisting of ethylamine salt, butylamine salt, pentamethylenediamine salt, hexamethylenediamine salt, 1,4-diaminobutane salt, 1,8-diaminooctane salt, aniline salt, p-phenylenediamine salt, m-phenylenediamine salt, toluenediamine salt, 1,5-naphthalenediamine salt, diphenylmethanediamine salt, dicyclohexylmethanediamine salt, m-cyclohexyldimethylenediamine salt, isophoronediamine salt, methylcyclohexanediamine salt, and trans-1,4-cyclohexanediamine salt.

[0099] In certain embodiments, the amine salt is selected from one or more of the following groups: pentamethylenediamine carbonate, hexamethylenediamine carbonate, isophoronediamine carbonate, and methylcyclohexanediamine carbonate. In certain embodiments, the amine salt is pentamethylenediamine carbonate. In certain embodiments, the amine salt is 1,5-pentamethylenediamine carbonate.

[0100] In the present application, the "first mixture containing an amine salt" contains, in addition to the amine salt, impurities such as other salts, sugars, and bacteria.

[0101] The first mixture comprising an amine salt can be prepared using any method known in the art. In certain embodiments, the first mixture comprising an amine salt is prepared by an enzyme-catalyzed method. In certain embodiments, the first mixture comprising pentamethylenediamine carbonate is prepared by introducing carbon dioxide into a lysine solution to form lysine carbonate (bicarbonate), and then reacting the lysine carbonate (bicarbonate) with a lysine decarboxylase to produce pentamethylenediamine carbonate.

[0102] In certain embodiments, carbon dioxide is introduced into the lysine solution until the pH reaches 7 to 9 (e.g., 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, or any specific pH value in a range between any two of the above values), and then the supply of carbon dioxide is stopped.

[0103] In certain embodiments, the concentration of the lysine carbonate (bicarbonate) solution formed is 200 g / L to 700 g / L, for example, 210 g / L, 220 g / L, 230 g / L, 240 g / L, 250 g / L, 260 g / L, 270 g / L, 280 g / L, 285 g / L, 290 g / L, 300 g / L, 350 g / L, 400 g / L, 450 g / L, 500 g / L, 510 g / L g / L, 520 g / L, 530 g / L, 540 g / L, 550 g / L, 560 g / L, 570 g / L, 580 g / L, 590 g / L, 600 g / L, 610 g / L, 620 g / L, 630 g / L, 640 g / L, 650 g / L, 660 g / L, 670 g / L, 680 g / L, 690 g / L, 700 g / L, or any specific concentration within a range between any two of the above values.

[0104] In certain embodiments, the lysine decarboxylase is a purified lysine decarboxylase. In certain embodiments, the lysine decarboxylase is derived from thalli expressing lysine decarboxylase. In certain embodiments, the thalli comprises wet thalli, a broken thalli solution, or immobilized thalli. In certain embodiments, the thalli is derived from recombinant engineered bacteria. In certain embodiments, the lysine decarboxylase is derived from recombinant engineered Escherichia coli bacteria expressing lysine decarboxylase. In certain embodiments, the lysine decarboxylase is derived from wet thalli of recombinant engineered Escherichia coli bacteria expressing lysine decarboxylase. In certain embodiments, the lysine decarboxylase is derived from a broken thalli of recombinant engineered Escherichia coli bacteria expressing lysine decarboxylase. In certain embodiments, the lysine decarboxylase is derived from immobilized thalli of recombinant engineered Escherichia coli bacteria expressing lysine decarboxylase.

[0105] In certain embodiments, the lysine (bi)carbonate reacts with lysine decarboxylase at a temperature of 20-40°C (e.g., 20°C, 25°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C or any specific temperature in the range between any two of the above values) to produce pentamethylenediamine carbonate.

[0106] In certain embodiments, the reaction time of lysine carbonate (bicarbonate) and lysine decarboxylase is 5 to 15 hours (e.g., 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours or any specific time within the range between any two of the above values).

[0107] In certain embodiments, when lysine content<0.5% (w / v), for example, 0.4%, 0.3%, 0.2%, 0.1% or even lower, it indicates that the catalytic reaction of lysine carbonate (bi) salt and lysine decarboxylase ends. Those skilled in the art can adopt the conventional means of this area to measure lysine content, for example, HPLC method.

[0108] In some embodiments, after the catalytic reaction of lysine carbonate (bi) salt and lysine decarboxylase ends, further comprising removing the residue in the reaction solution. In some embodiments, the residue comprises large particle impurities, such as impurities such as cells, bacterial fragments, aggregates, and flocculent bodies, and also comprises small molecule impurities, such as impurities such as nucleic acids and nucleic acid fragments, proteins, and culture medium components in bacterial culture. Those skilled in the art can use conventional separation means to remove the residue of the catalyst described in the mixture according to their actual needs, such as, one or more of the various means such as filtration, centrifugation, microfiltration, and ultrafiltration.

[0109] In certain embodiments, the filtration is achieved by using filter paper or filter cloth. The filter paper or filter cloth described in the present invention can be commercially available filter paper or filter cloth, such as filter paper or filter cloth produced by companies such as GE Healthcare Life Sciences, Shi Bichun, Asahi Chemical Corporation. In certain embodiments, the pore size of the filter paper or filter cloth is 10 to 150 μm, such as 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm or any value between any two of the above numerical ranges. Those skilled in the art can select a suitable filter paper or filter cloth pore size to remove impurities according to the size of the impurities.

[0110] In certain embodiments, the microfiltration is achieved by passing the reaction solution through a microfiltration membrane. The microfiltration membrane described in the present invention can be a commercially available microfiltration membrane, such as the microfiltration hollow fiber membrane series produced by GE Healthcare Life Sciences, Shi Bichun, Asahi Chemical Corporation, etc. In certain embodiments, the pore size of the microfiltration membrane is 0.1μm to 0.6μm, such as 0.1μm, 0.15μm, 0.2μm, 0.22μm, 0.25μm, 0.3μm, 0.35μm, 0.4μm, 0.45μm, 0.5μm, 0.55μm, 0.6μm or any value between any two of the above numerical ranges. Those skilled in the art can select a suitable microfiltration membrane pore size to remove impurities according to the size of the impurities.

[0111] In certain embodiments, the ultrafiltration is achieved by passing the reaction solution through an ultrafiltration membrane. The ultrafiltration membrane described in the present invention can be a commercially available ultrafiltration membrane, such as the ultrafiltration hollow fiber membrane series produced by GE Healthcare Life Sciences, Shi Bichun Company, Asahi Chemical Industry Co., Ltd., etc. In certain embodiments, the ultrafiltration membrane is a hollow fiber ultrafiltration membrane with a pore size of 5kD to 500kD, such as a hollow fiber ultrafiltration membrane with a pore size of 5kD, 6kD, 7kD, 8kD, 9kD, 10kD, 20kD, 30kD, 40kD, 50kD, 60kD, 70kD, 80kD, 90kD, 100kD, 150kD, 200kD, 250kD, 300kD, 350kD, 400kD, 450kD, 500kD or any value between any two numerical ranges above. Those skilled in the art can select a suitable ultrafiltration membrane pore size to remove impurities according to the size of the impurities.

[0112] In certain embodiments, the process further comprises concentrating the prepared pentamethylenediamine carbonate. In certain embodiments, the concentration is achieved by reducing pressure. For example, the reaction solution after filtration, microfiltration, or ultrafiltration is pumped into a concentration device for concentration under reduced pressure to 1 / 3, 1 / 4, 1 / 5, 1 / 6, 1 / 7, 1 / 8, 1 / 9, 1 / 10 of the original volume, or any value between any two of the above values.

[0113] In certain embodiments, the process further comprises crystallizing the prepared pentamethylenediamine carbonate. In certain embodiments, the crystallization is achieved by lowering the temperature and adding an organic solvent (e.g., methanol, ethanol, isopropanol, etc.). For example, 1, 2, 3, or 4 times the volume of an organic solvent is added dropwise to the concentrated reaction solution, and crystallization is carried out under low temperature conditions (e.g., 10°C, 5°C, or lower). In certain embodiments, the crystallization is carried out by vacuum drying. For example, the prepared pentamethylenediamine carbonate is dried in a vacuum oven at 50-70°C (e.g., 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, or any specific temperature between any two specific numerical ranges above) to obtain pentamethylenediamine carbonate.

[0114] In certain embodiments, a lysine carbonate (bicarbonate) solution having a concentration of 500 to 650 g / L (e.g., 500 g / L, 510 g / L, 520 g / L, 530 g / L, 540 g / L, 550 g / L, 560 g / L, 570 g / L, 580 g / L, 590 g / L, 600 g / L, 610 g / L, 620 g / L, 630 g / L, 640 g / L, 650 g / L or any specific concentration within the range between any two values ​​above) is prepared, and then the prepared lysine carbonate (bicarbonate) solution is added to the lysine carbonate solution. Wet cells of an engineered Escherichia coli bacterium containing lysine decarboxylase are added to an acid carbonate (bicarbonate) solution and subjected to an enzymatic reaction for 8 to 12 hours (e.g., 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, or any specific time within a range between any two of the above values). The reaction temperature is controlled at 35 to 40° C. (e.g., 35° C., 36° C., 37° C., 38° C., 39° C., 40° C., or any specific temperature within a range between any two of the above values). The reaction is terminated when the lysine content measured by HPLC is less than 0.5% (w / v). The residue in the reaction solution is then removed and the product is dried in a vacuum oven at 50 to 70° C. to obtain a crude product of pentamethylenediamine carbonate.

[0115] In certain embodiments, a 570 g / L lysine carbonate (bicarbonate) solution is prepared, and wet cells of engineered Escherichia coli bacteria containing lysine decarboxylase are added to the prepared lysine carbonate (bicarbonate) solution for an enzymatic reaction for 10 hours. The reaction temperature is controlled at 37°C, and the reaction is terminated when the lysine content measured by HPLC is less than 0.5% (w / v). The residue in the reaction solution is then removed, and the product is dried in a vacuum oven at 50-70°C to obtain crude pentamethylenediamine carbonate.

[0116] In certain embodiments, a 600 g / L lysine carbonate (bicarbonate) solution is prepared, and wet cells of engineered Escherichia coli bacteria containing lysine decarboxylase are added to the prepared lysine carbonate (bicarbonate) solution for an enzymatic reaction for 10 hours. The reaction temperature is controlled at 37°C, and the reaction is terminated when the lysine content measured by HPLC is less than 0.5% (w / v). The residue in the reaction solution is then removed, and the product is dried in a vacuum oven at 50-70°C to obtain a crude pentamethylenediamine derivative.

[0117] The first mixture comprising the amine salt can be in any suitable state. In certain embodiments, the first mixture comprising the amine salt is in a solid state. In certain embodiments, the first mixture comprising the amine salt is in a powdered state. Without being limited by any theory, it is believed that a powdered first mixture is more conducive to the purification of the amine salt.

[0118] In certain embodiments, the first mixture comprising an amine salt flows into the powder absorber through a valve under gravity. In certain embodiments, the valve is a rotary feeding valve. The amount of the first mixture delivered to the powder absorber can be controlled by the valve (e.g., a rotary feeding valve). In certain embodiments, the amount of the first mixture delivered to the powder absorber is controlled to be 1 to 5 kg / h (e.g., 1 kg / h, 1.5 kg / h, 2 kg / h, 2.5 kg / h, 3 kg / h, 3.5 kg / h, 4 kg / h, 4.5 kg / h, 5 kg / h or any specific value within the range between any two of the above values) by the valve (e.g., a rotary feeding valve). In certain embodiments, the amount of the first mixture delivered to the powder absorber is controlled to be 2 kg / h by the valve (e.g., a rotary feeding valve).

[0119] In some embodiments, the valve (e.g., a rotary feeding valve) is connected to the powder absorber by a delivery pipe. In some embodiments, the inner diameter of the delivery pipe is 1 to 10 mm (e.g., 1 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm or any specific numerical value between any two specific numerical ranges). In some embodiments, the inner diameter of the delivery tube is 2 to 4 mm (e.g., 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4 mm, or any specific value between any two specific numerical ranges above). In some embodiments, the inner diameter of the delivery tube is 2 to 3.8 mm (e.g., 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, or any specific value between any two specific numerical ranges above).

[0120] 2. Carrier gas

[0121] In this application, a "carrier gas" refers to a gas that does not chemically react with the substances in the system and is primarily used to provide kinetic energy or velocity to the materials. In certain embodiments, the carrier gas is an inert gas. In certain embodiments, the carrier gas is selected from the group consisting of nitrogen, argon, helium, hydrogen, oxygen, carbon dioxide, clean dry air, or other gases that are stable at room temperature and atmospheric pressure.

[0122] In certain embodiments, at least a portion (e.g., at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%) of the carrier gas, or all of it, is derived from by-product gases of the reaction system. For example, in the phosgenation process for preparing isocyanates, pentamethylenediamine carbonate reacts with phosgene to produce pentamethylene diisocyanate, and a large amount of by-product gases, such as carbon dioxide, are generated. If the generated by-product gases are directly discharged, not only will serious environmental pollution be caused, but also production costs will be increased. The present invention skillfully recycles the by-product gas generated in the reaction system, thereby reducing the by-product treatment cost and reducing the pollution to the environment.

[0123] In certain embodiments, the carrier gas is carbon dioxide. In certain embodiments, at least a portion (e.g., at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%) of the carrier gas is derived from byproduct gases of the reaction system.

[0124] In some embodiments, the carrier gas is compressed (for example, by a compressor) to reduce the pressure of the carrier gas. In some embodiments, the carrier gas is compressed to 0.2 to 0.6 MPa (for example, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.55 MPa, 0.6 MPa or any specific numerical value between any two numerical ranges). In some embodiments, the compressed carrier gas is passed into a powder aspirator, and a negative pressure zone is formed in the powder aspirator. In some embodiments, a negative pressure zone is formed in the powder aspirator after the carrier gas passes through the throat diameter of the powder aspirator. In some embodiments, the powder aspirator is in a venturi form. In some embodiments, the powder aspirator is in a venturi-like form.

[0125] Without being limited by theory, it is believed that forming a negative pressure zone within the powder aspirator further facilitates thorough mixing of the first mixture containing the amine salt and the carrier gas. For example, a Venturi design in the powder aspirator can facilitate a more continuous purification process. By controlling the material ratio of the first mixture to the carrier gas, the channel is prevented from clogging and accumulation of material. In certain embodiments, the first mixture containing the amine salt and the carrier gas are mixed within the negative pressure zone of the powder aspirator to produce the second mixture.

[0126] In some embodiments, the flow rate of the carrier gas is 0.1 to 1 m 3 / h (for example, 0.1m 3 / h, 0.2m 3 / h、0.3m 3 / h、0.4m 3 / h、0.5m 3 / h、0.6m 3 / h、0.7m 3 / h、0.8m 3 / h、0.9m 3 / h、1m 3 / h or any specific value between any two numerical ranges above).

[0127] 3. Mix

[0128] In certain embodiments, the first mixture comprising an amine salt is mixed with a carrier gas to obtain a second mixture, wherein the second mixture is a gas-powder mixture. In certain embodiments, the first mixture comprising an amine salt is mixed with a carrier gas in a powder inhaler to obtain a second mixture, wherein the second mixture is a gas-powder mixture.

[0129] In certain embodiments, the first mixture comprising the amine salt is mixed with the carrier gas at ambient temperature. In certain embodiments, the ambient temperature is in the range of -10°C to 40°C (e.g., -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, or any specific value between any two of the above ranges).

[0130] In certain embodiments, a stirring device is provided in the powder absorber to allow the first mixture containing the amine salt to be more fully mixed with the carrier gas. The fully mixed second mixture enters a downstream container for the next step.

[0131] Step (2)

[0132] In the method for purifying amine salts provided herein, step (2) comprises preheating the second mixture obtained in step (1) in a heater so that the outlet temperature of the heater is close to or equal to the sublimation temperature of the amine salt.

[0133] In certain embodiments, in step (2), the heating temperature is controlled so that the outlet temperature of the heater is a temperature at which the amine salt sublimes but does not decompose. In certain embodiments, in step (2), the second mixture obtained in step (1) is heated to 70-140°C (e.g., 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C or any specific temperature between any two numerical ranges above).

[0134] In certain embodiments, the heating in step (2) is carried out in a heater having a heating medium. The heating medium can be any heating medium known in the prior art. In certain embodiments, the heating medium is selected from the following group: inorganic superconducting heat transfer medium, composite heat-conducting fiber medium, graphite heat-conducting medium, carbon fiber heat-conducting medium, heat-conducting oil, high-pressure steam or molten salt. In certain embodiments, the heating medium is heat-conducting oil. In certain embodiments, the heat-conducting oil is selected from one or more of the following groups: alkylnaphthalene, alkylbenzene, dibenzyltoluene and hydrogenated terphenyl. In certain embodiments, the heat-conducting oil causes the heating temperature to reach or exceed the sublimation temperature of the amine salt. For example, the heat-conducting oil causes the heating temperature to reach or exceed 70 to 130°C (for example, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C or any specific temperature between any two numerical ranges above).

[0135] In certain embodiments, the outer surface of the inner tube of the heater is coated with a heat-conducting metal, such as aluminum, copper, silver, aluminum alloy, copper alloy, silver alloy, etc. Coating the outer surface of the inner tube of the heater with a heat-conducting metal can further save energy, thereby reducing energy consumption and saving costs.

[0136] Without being bound by theory, it is believed that a preheating step prior to sublimation of the amine salt is particularly preferred in the amine salt purification method described herein. For example, prior to sublimation of the amine salt (e.g., pentamethylenediamine derivative), the mixture containing the amine salt (e.g., pentamethylenediamine derivative) is preheated to, for example, 100-140°C (e.g., 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, or any specific temperature between any two numerical ranges). If the first mixture containing the amine salt and the carrier gas are directly introduced into the separator for flash sublimation without preheating using a heater, the amine salt is unevenly heated in the separator or fails to fully sublime in the separator, resulting in a low yield of the amine salt and a large amount of pentamethylenediamine among the solid impurities.

[0137] The inventors have found through a series of experimental designs that a series of factors such as the carrier gas flow rate in the preheating step, the amount of amine salt delivered, the heating temperature, and the inner diameter of the delivery pipe will affect the purification yield of the amine salt. In some embodiments, the carrier gas flow rate is 0.4 to 1 m 3 / h (for example, 0.4m 3 / h、0.5m 3 / h、0.6m 3 / h、0.7m 3 / h、0.8m 3 / h、0.9m 3 / h、1m 3 / h or any specific value between any two numerical ranges above), the amine salt delivery rate is 1-5 kg / h (for example, 1 kg / h, 1.5 kg / h, 2 kg / h, 2.5 kg / h, 3 kg / h, 3.5 kg / h, 4 kg / h, 4.5 kg / h, 5 kg / h or any specific value within the range between any two numerical ranges above), and the inner diameter of the delivery pipe is 2-3.8 mm (for example, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm , 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm or any specific value between any two specific numerical ranges above), the heater outlet temperature is 100-130℃ (for example, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃ or any specific temperature between any two numerical ranges above).

[0138] Step (3)

[0139] In the method for purifying an amine salt provided in the present application, step (3) comprises separating the amine salt preheated in step (2) at the sublimation temperature of the amine salt.

[0140] In certain embodiments, step (3) comprises flash-subliming the preheated amine salt in step (2) within a separator to form a gaseous amine salt. Without being limited by any theory, it is believed that swirling the preheated amine salt obtained in step (2) along a draft tube within the separator is preferred because this arrangement can increase the residence time of the preheated amine salt within the separator, thereby allowing the amine salt to sublime more fully and ensuring a higher yield of the purified amine salt. In certain embodiments, to ensure a better separation effect, a heating jacket is provided on the outer wall of the separator, and / or a heating tube is provided within the separator.

[0141] In certain embodiments, the gaseous amine salt is discharged through the exhaust port at the upper end of the separator, and the solid impurities are discharged from the discharge port at the lower end of the separator, thereby achieving purification of the amine salt.

[0142] In certain embodiments, the gaseous amine salt discharged from the exhaust port at the upper end of the separator is subjected to a desublimation treatment. Without being bound by any theory, it is believed that the lower the desublimation temperature, the more favorable the desublimation of the gaseous amine salt. In certain embodiments, the obtained gaseous amine salt is desublimated at 30-50°C (e.g., 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C, 50°C or any specific temperature between any two of the above numerical ranges).

[0143] In certain embodiments, the present application provides a method for purifying pentamethylenediamine carbonate, wherein the method comprises: mixing a first mixture comprising pentamethylenediamine carbonate with carbon dioxide gas to obtain a second mixture; preheating the second mixture in a heater so that the heater outlet temperature is close to or equal to the sublimation temperature of pentamethylenediamine carbonate; and separating the preheated pentamethylenediamine carbonate at the sublimation temperature of pentamethylenediamine carbonate. In certain embodiments, the sublimation temperature of pentamethylenediamine carbonate is 70-140°C (e.g., 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, or any specific temperature between any two numerical ranges above). In certain embodiments, the sublimation temperature of pentamethylenediamine carbonate is 70-130°C. In certain embodiments, the heater outlet temperature is 120°C. In certain embodiments, the gaseous pentamethylenediamine carbonate discharged from the exhaust port at the upper end of the separator is subjected to a desublimation treatment. In certain embodiments, the obtained gaseous pentamethylenediamine carbonate is subjected to a desublimation treatment at 30-50° C. (e.g., 30° C., 31° C., 32° C., 33° C., 34° C., 35° C., 36° C., 37° C., 38° C., 39° C., 40° C., 41° C., 42° C., 43° C., 44° C., 45° C., 46° C., 47° C., 48° C., 49° C., 50° C., or any specific temperature between any two of the above numerical ranges).

[0144] In another aspect, the present application also provides a method for purifying a pentamethylenediamine derivative, wherein the method comprises heating a mixture containing the pentamethylenediamine derivative described herein to the sublimation temperature of the pentamethylenediamine derivative to obtain a gaseous pentamethylenediamine derivative. All contents described in the "Pentamethylenediamine Derivatives" section of this application also apply to the description of the pentamethylenediamine derivative purification method in this section and are therefore not further elaborated.

[0145] In certain embodiments, the pentamethylenediamine derivative in the mixture has a purity of 80% or greater (e.g., 85% or greater, 86% or greater, 87% or greater, 88% or greater, 89% or greater, 90% or greater, 91% or greater, 92% or greater, 93% or greater, 94% or greater, 95% or greater, or 96% or greater). The inventors of the present application unexpectedly discovered that a gaseous pentamethylenediamine derivative of higher purity can be obtained by heating the mixture containing the pentamethylenediamine derivative described herein to a certain temperature to cause the pentamethylenediamine derivative to sublime. The obtained higher-purity pentamethylenediamine derivative can then react with phosgene to prepare pentamethylene diisocyanate. The purity of the gaseous pentamethylenediamine derivative obtained by this method can reach 98% or greater, thus meeting the requirements of large-scale industrial production.

[0146] The mixture containing the pentamethylenediamine derivative can be sublimed using methods common in the art. For example, the mixture containing the pentamethylenediamine derivative can be heated by controlling parameters such as temperature and air pressure so that the pentamethylenediamine derivative is converted into a gaseous state while the impurities remain in the mixture. For another example, the mixture containing the pentamethylenediamine derivative can be heated using a commercial purification device (e.g., a flash evaporation device) so that the pentamethylenediamine derivative is converted into a gaseous state while the impurities remain in the mixture. In certain embodiments, the heating temperature is controlled to a temperature at which the pentamethylenediamine derivative sublimes but does not decompose. Without being limited by any theory, it is preferred to control the heating temperature to a temperature at which the pentamethylenediamine derivative sublimes but does not decompose because this setting can ensure that the purity of the obtained gaseous pentamethylenediamine derivative is sufficiently high and that the yield of the pentamethylenediamine derivative after purification is sufficiently high.

[0147] In certain embodiments, the sublimation temperature of the pentamethylenediamine derivative is 70-140°C (e.g., 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, or any specific temperature between any two numerical ranges above). In certain embodiments, the mixture comprising the pentamethylenediamine derivative is heated to 70-140°C (e.g., 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, or any specific temperature between any two numerical ranges above).

[0148] In certain embodiments, the method for purifying pentamethylenediamine derivatives provided herein comprises flash-subliming the preheated pentamethylenediamine derivatives in a separator to form gaseous pentamethylenediamine derivatives.

[0149] In certain embodiments, the method for purifying pentamethylenediamine derivatives provided herein further comprises desubliming the obtained gaseous pentamethylenediamine derivative. Without being bound by any theory, it is believed that the lower the desublimation temperature, the more favorable the desublimation of the gaseous pentamethylenediamine derivative. In certain embodiments, the obtained gaseous pentamethylenediamine derivative is desublimed at 30-50°C (e.g., 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, or any specific temperature between any two of the above numerical ranges).

[0150] In certain embodiments, the present application provides a method for purifying a PDA·CO2 covalent compound, wherein the method comprises: preheating a mixture containing the PDA·CO2 covalent compound to a temperature close to or equal to the sublimation temperature of the PDA·CO2 covalent compound; and separating the preheated PDA·CO2 covalent compound at the sublimation temperature of the PDA·CO2 covalent compound. In certain embodiments, the sublimation temperature of the PDA·CO2 covalent compound is 70 to 140°C (e.g., 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, or any specific temperature between any two numerical ranges above). In certain embodiments, the obtained gaseous PDA·CO2 covalent compound is subjected to a desublimation treatment. In certain embodiments, the obtained gaseous PDA·CO2 covalent compound is desublimated at 30-50°C (e.g., 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C, 50°C or any specific temperature between any two numerical ranges).

[0151] In addition, the pentamethylenediamine derivative purified by the method provided in this application contains substantially no volatile organic compounds (VOCs). Pentamethylenediamine diisocyanate prepared by reacting the purified pentamethylenediamine derivative with phosgene also contains substantially no VOCs.

[0152] The method for purifying amine salts (e.g., pentamethylenediamine derivatives) provided in the present application does not include a step of alkalizing the first mixture containing the amine salt using an alkaline substance (e.g., sodium hydroxide, potassium hydroxide, ammonia water, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, or any combination thereof). In conventional methods for preparing isocyanates, the amine salt is converted into a free amine by the alkalinization treatment, and then a subsequent phosgenation reaction is carried out to generate the isocyanate. In the method of the present application, however, the amine salt is not converted into a free amine by an alkalinization treatment, but is directly purified, and the purified amine salt is then directly subjected to a phosgenation reaction. The method of directly purifying amine salts of the present invention can not only reduce the investment cost of equipment, but also avoid the operating steps of separating free amine and water, thereby reducing energy consumption.

[0153] In addition, the method for purifying amine salts provided in this application also has at least the following advantages:

[0154] (1) Using the by-product CO2 generated by the reaction as the gas source for material transportation avoids the use of rotating equipment, reduces power consumption, and improves equipment stability. The reuse of by-products maximizes resources.

[0155] (2) When the carrier gas (e.g., CO2) flows through the throat of the powder absorber, the gas pressure is converted into kinetic energy and a negative pressure zone is formed, causing the amine salt (e.g., pentamethylenediamine carbonate) to be sucked into the powder absorber. The use of a simple static device replaces the function of the dynamic device to transport the powder;

[0156] (3) Through reasonable structural design, the use of static equipment separators allows the material to fully react in the equipment, playing the role of dynamic equipment;

[0157] (4) A heating tube is added to the middle of the separator. The outer circumference and the internal heating tube of the separator are heated by the heat medium, which avoids the low temperature at the center of the equipment affecting the purification effect of the equipment;

[0158] (5) The use of the guide tube in the separator prolongs the residence time of the material and enhances the separation effect; at the same time, it increases the centrifugal force of the cyclone and realizes the rapid separation of gas and solid.

[0159] Method for preparing isocyanate

[0160] In another aspect, the present application also provides a method for preparing isocyanate, wherein the method comprises:

[0161] (a) providing an amine salt stream and a phosgene stream and mixing them in a material mixing device;

[0162] (b) spraying the mixture obtained in step (a) into the diffusion port of the reactor, and using a baffle disposed in the reactor near the feed end to resist the lateral velocity of the material at the discharge end of the material mixing device;

[0163] (c) The amine salt and phosgene in the mixture enter the reaction zone of the reactor and react in the reaction zone to generate isocyanate.

[0164] In certain embodiments, the method for preparing isocyanate provided herein further comprises step (d): collecting the isocyanate prepared in step (c).

[0165] In certain embodiments, the present application provides a method for preparing pentamethylene diisocyanate, wherein the method comprises:

[0166] (a) providing a pentamethylenediamine carbonate stream and a phosgene stream, and mixing them in a material mixing device;

[0167] (b) spraying the mixture obtained in step (a) into the diffusion port of the reactor, and using a baffle disposed in the reactor near the feed end to resist the lateral velocity of the material at the discharge end of the material mixing device;

[0168] (c) Pentamethylenediamine carbonate and phosgene in the mixture enter the reaction zone of the reactor and react in the reaction zone to generate pentamethylene diisocyanate.

[0169] In certain embodiments, the method for preparing pentamethylene diisocyanate provided herein further comprises step (d): collecting the pentamethylene diisocyanate prepared in step (c).

[0170] In this application, "isocyanate" refers to a class of compounds containing one or more (e.g., two, three, four, five, six, seven, eight, nine, ten or more) isocyanate groups (RN=C=O), including aliphatic isocyanates, aromatic isocyanates, unsaturated isocyanates, halogenated isocyanates, thioisocyanates, phosphorus-containing isocyanates, inorganic isocyanates, and blocked isocyanates. In certain embodiments, the isocyanate in this application is a diisocyanate. In certain embodiments, the isocyanate in this application is an aliphatic diisocyanate or an aromatic diisocyanate. In certain embodiments, the isocyanate in this application includes aromatic isocyanates and aliphatic isocyanates. For example, the aromatic isocyanate includes diphenylmethylene diisocyanate as a pure isomer or as a mixture of isomers, toluene diisocyanate, 2,6-xylene isocyanate, 1,5-naphthalene diisocyanate, and the like as a pure isomer or as a mixture of isomers. Aliphatic isocyanates include methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, isobutyl isocyanate, tert-butyl isocyanate, amyl isocyanate, tert-amyl isocyanate, isopentyl isocyanate, neopentyl isocyanate, hexyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, etc. In certain embodiments, the isocyanate in the present application is selected from the group consisting of pentamethylene diisocyanate, hexamethylene diisocyanate, p-phenylene diisocyanate, and toluene diisocyanate. In certain embodiments, the isocyanate in the present application is pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), or methylcyclohexane diisocyanate (HTDI).

[0171] The following describes in detail step (a), step (b), step (c), and optional step (d) of the method for preparing isocyanate described in the present application.

[0172] Step (a)

[0173] In the method for preparing isocyanate provided in the present application, step (a) comprises providing an amine salt stream and a phosgene stream, and mixing the streams in a material mixing device.

[0174] In certain embodiments, the amine salt stream in step (a) is an amine salt (e.g., pentamethylenediamine carbonate) purified according to the method for purifying amine salts described herein. All of the contents described in the "Method for Purifying Amine Salts" section of this application also apply to the description of the isocyanate preparation method in this section and are therefore not further described here.

[0175] During the preparation of isocyanates, a large excess of phosgene is often required. This is because when the phosgene concentration is insufficient, the isocyanate formed reacts with the excess amine to form urea or other highly viscous solid byproducts. Therefore, to prevent the formation of byproducts, phosgene is preferably provided in excess. For example, in certain embodiments, the phosgene stream in step (a) is in stoichiometric excess based on the amino groups in the amine salt stream. For example, the molar ratio of phosgene to the amino group of the amine salt is typically 1.1:1-50:1 (e.g., 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, 10:1, 11:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1 and ranges therebetween). In certain embodiments, phosgene is used in a stoichiometric excess of 0% to 250% (e.g., 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, etc.) of the theoretical value based on the amino groups of the amine salt in the reactor. When the amine salt stream (and / or phosgene stream) in step (a) enters the reactor via multiple amine salt (and / or phosgene)-containing substreams, the total phosgene stream generated by the sum of the multiple phosgene-containing substreams is in stoichiometric excess based on the amino groups of the total amine salt stream generated by the sum of the multiple amine salt-containing substreams.

[0176] In certain embodiments, the ratio of the feed amounts (by mole) of the phosgene stream to the amine salt stream in step (a) is 7:1 to 25:1 (e.g., 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, or any number between any two of the above ratios). Preferably, the ratio of the feed amounts (by mole) of the phosgene stream to the amine salt stream in step (a) is 8:1 to 20:1. In certain embodiments, the ratio of the feed amounts (by mole) of the phosgene stream to the amine salt stream in step (a) is 8:1.

[0177] The delivery rate of the amine salt stream and the phosgene stream can be controlled by adjusting a flow meter, a valve, etc. In certain embodiments, the delivery rate of the amine salt stream in step (a) is 0.8 to 2.5 kg / h (e.g., 0.8 kg / h, 0.9 kg / h, 1 kg / h, 1.1 kg / h, 1.2 kg / h, 1.3 kg / h, 1.4 kg / h, 1.5 kg / h, 1.6 kg / h, 1.7 kg / h, 1.8 kg / h, 1.9 kg / h, 2 kg / h, 2.1 kg / h, 2.2 kg / h, 2.3 kg / h, 2.4 kg / h, 2.5 kg / h or any specific value between any two numerical ranges). In certain embodiments, the delivery rate of the phosgene stream in step (a) is 4 to 12 kg / h (e.g., 4.5 kg / h, 5 kg / h, 5.5 kg / h, 6 kg / h, 6.5 kg / h, 7 kg / h, 7.5 kg / h, 8 kg / h, 8.5 kg / h, 9 kg / h, 9.5 kg / h, 10 kg / h, 10.5 kg / h, 11 kg / h, 11.5 kg / h, 12 kg / h, or any specific value between any two numerical ranges).

[0178] The phosgene contained in the phosgene stream described in step (a) can be fresh phosgene or recycled phosgene. The term "fresh phosgene" refers to a phosgene-containing stream that has not yet been recycled from the phosgenation process and has not yet passed through any reaction stage involving a phosgene reaction after phosgene is synthesized from chlorine and carbon monoxide. The term "recycled phosgene" refers to a phosgene-containing stream collected from the tail gas during the reaction process of preparing isocyanates from the phosgenation process. As mentioned above, in the process of preparing isocyanates by the gas phase method, it is often necessary to use excess phosgene, so the reaction tail gas will contain a large amount of phosgene, and recycling the phosgene in the tail gas can achieve the purpose of reducing production costs. In certain embodiments, the phosgene stream described in step (a) exists in liquid form. In certain embodiments, the amine salt stream described in step (a) is solid, and the phosgene stream is gaseous.

[0179] In certain embodiments, the amine salt stream and the phosgene stream in step (a) are mixed at, for example, any temperature between 5 and 75°C, such as 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, or any value between any two of the above values. In certain embodiments, the amine salt stream and the phosgene stream in step (a) are mixed at any temperature between 8 and 71°C. In certain embodiments, the mixing can be carried out at any constant temperature between 5 and 75°C or at a varying temperature between 5 and 75°C. In certain embodiments, the mixing can be carried out at any constant temperature between 8 and 71°C or at a varying temperature between 8 and 71°C.

[0180] In certain embodiments, the amine salt stream is first stored in a solid storage tank before entering the material mixing device, and an inert gas (e.g., nitrogen, helium, argon, etc.) is introduced into the solid storage tank for replacement. In certain embodiments, the discharge port of the solid storage tank is connected to the material mixing device via a solid conveying pipe. In certain embodiments, at least one solid storage tank is provided, adjacent solid storage tanks are connected by pipes, and opening and closing parts are provided on the pipes between adjacent solid storage tanks, and the opening and closing parts are used to control the feeding order and feeding amount of the solid storage tanks.

[0181] In certain embodiments, the phosgene stream is stored in a gas storage tank before entering the material mixing device, and the pressure of the gas storage tank is maintained at 0.05-0.1 MPa (e.g., 0.06 MPa, 0.07 MPa, 0.08 MPa, 0.09 MPa, 0.1 MPa, etc.).

[0182] In certain embodiments, the phosgene stream is pressurized before entering the material mixing device, for example, to a pressure between 0.1 MPa and 0.7 MPa (for example, 0.15 MPa, 0.16 MPa, 0.17 MPa, 0.18 MPa, 0.19 MPa, 0.2 MPa, 0.21 MPa, 0.22 MPa, 0.23 MPa, 0.24 MPa, 0.25 MPa, 0.26 MPa, 0.27 MPa, 0.28 MPa, 0.29 MPa, 0.3 MPa, 0.31 MPa, 0.32 MPa, 0.33 MPa, 0.34 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.55 MPa, 0.6 MPa, 0.65 MPa, 0.7 MPa or any value within a range between any two of the above values).

[0183] In certain embodiments, no solvent is used in step (a). In conventional methods for preparing isocyanates, a solvent (e.g., an organic solvent) is typically used to disperse the amine salt, or an inert carrier gas (e.g., nitrogen, carbon dioxide, carbon monoxide, helium, or argon) is used to assist in gasification of the amine salt and achieve a more suitable dispersion effect. However, in the present invention, the inventors unexpectedly discovered that when mixing the amine salt and phosgene in step (a), no solvent (particularly, an organic solvent) or inert carrier gas is required, and the reaction gas (i.e., the phosgene stream) can be directly used as the carrier gas to transport the amine salt to the reactor.

[0184] Step (b)

[0185] In the method for preparing isocyanate provided in the present application, step (b) includes spraying the mixture obtained in step (a) into the diffusion port of the reactor, and a baffle arranged in the reactor near the feed end is used to resist the lateral velocity of the material at the discharge end of the material mixing device.

[0186] Since the mixture ejected from the discharge end of the material mixing device is relatively dispersed, in order to prevent the material from sticking to the wall, a baffle (e.g., a circular baffle) is installed at the injection inlet of the reactor body. The baffle needs to be at a certain distance from the reaction tube wall (e.g., between 1 and 3 cm), and the bottom end of the baffle should be above the edge of the heat exchange jacket (e.g., the spacing is between 1 and 2 cm), so that there is a certain gradient between the temperature of the baffle and the temperature of the reaction tube wall.

[0187] In some embodiments, the reactor described in step (b) is a pipeline reactor. In this application, "pipeline reactor" may also be referred to as a tubular reactor, which refers to a continuously operated reactor that is tubular and has a large aspect ratio, and is a plug flow reactor. The length of the pipeline reactor can be adjusted, and its characteristic is that a continuous reaction can be achieved, and the reaction will not be back-mixed. Pipeline reactors generally include main types such as horizontal tubular reactors, vertical tubular reactors, coil-type pipeline reactors, and U-shaped tubular reactors. In some embodiments, the pipeline reactor is a coil-type pipeline reactor. Depending on the requirements such as reaction output, pipeline reactors with different inner diameters and / or volumes can be used. The pressure of the reaction can be adjusted by adjusting the inner diameter of the pipeline reactor. For example, if the inner diameter is too large, it may result in incomplete reaction of amine salts and phosgene; if the inner diameter is too small, it may cause pipe blockage. In certain embodiments, the inner diameter of the tube reactor used in the present application is 50 to 180 mm (e.g., 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 161 mm, 162 mm, 163 mm, 164 mm, 165 mm, 166 mm, 167 mm, 168 mm, 169 mm, 170 mm, 180 mm, or any number between any two numerical ranges). In certain embodiments, the inner diameter of the tube reactor used in the present application is 150 to 170 mm (e.g., 150 mm, 155 mm, 160 mm, 161 mm, 162 mm, 163 mm, 164 mm, 165 mm, 166 mm, 167 mm, 168 mm, 169 mm, 170 mm, or any number between any two numerical ranges). In certain embodiments, the inner diameter of the pipeline reactor used in the present application is 160 to 170 mm (160 mm, 161 mm, 162 mm, 163 mm, 164 mm, 165 mm, 166 mm, 167 mm, 168 mm, 169 mm, 170 mm or any numerical value between any two numerical ranges). In certain embodiments, the pipeline reactor is a pipeline reactor with an inner diameter of 168 mm and a total length of 10 meters. In certain embodiments, the pipeline reactor is a vertical pipeline reactor with an inner diameter of 168 mm and a total length of 10 meters.

[0188] The pipeline reactor used in this application can be commercially available; it can also be prepared by itself, for example, using a self-purchased stainless steel pipe, formed by mold processing. In certain embodiments, the pipeline reactor used in the method for preparing isocyanate of the present invention is a 316L material non-welded one-piece steel pipe using DN100, and the jacket pipe uses a 316L material steel pipe using DMN150, wherein the jacket edge is 20cm from the valve at the top of the reaction tube; the mixed feed pipe in the reaction tube uses a DN20316L material stainless steel pipe, and the length of the deep reaction tube interior is 10cm, and a fan-shaped ring is welded below the reaction tube, and the ring vertical direction height is 4cm, and the ring edge welds a ring baffle, and the baffle height is 4cm, and the ring inner diameter is 6cm. The reaction tube height is 10m, and the reaction liquid storage tank is connected below the reaction tube.

[0189] In certain embodiments, the pressure of the tube reactor in step (b) is controlled between 50 and 140 KPa (e.g., 60 KPa, 65 KPa, 70 KPa, 75 KPa, 80 KPa, 85 KPa, 90 KPa, 95 KPa, 100 KPa, 105 KPa, 110 KPa, 115 KPa, 120 KPa, 125 KPa, 130 KPa, 135 KPa or any value between any two of the above numerical ranges, for example, 80 to 110 KPa).

[0190] Step (c)

[0191] In the method for preparing isocyanates provided herein, step (c) comprises introducing the amine salt and phosgene in the mixture into a reaction zone of the reactor, where they react to produce the isocyanate. In the reaction zone of the reactor, the amine salt (e.g., pentamethylenediamine carbonate) and the phosgene fully contact and react to produce an isocyanate (e.g., pentamethylene diisocyanate) reaction solution.

[0192] In certain embodiments, the reactor is a pipe reactor. In certain embodiments, the reactor is a vertical pipe reactor. In certain embodiments, the reactor is a vertical pipe reactor with a jacket. In certain embodiments, the jacket heat medium of the reactor is molten salt, and the heating temperature range is 350-370°C (for example, 355°C, 356°C, 357°C, 358°C, 359°C, 360°C, 361°C, 362°C, 363°C, 364°C, 365°C, 366°C, 367°C, 368°C, 369°C, 370°C or any value between any two numerical ranges above).

[0193] Step (d)

[0194] Optionally, the method for preparing isocyanate provided in the present application further comprises step (d): collecting the isocyanate prepared in step (c).

[0195] In certain embodiments, step (d) of the present application includes: providing a quenching zone at the outlet of the reactor so that the isocyanate obtained in step (c) contacts with a quenching medium stream passing into the quenching zone, thereby reducing the temperature of the isocyanate prepared in step (c) to below 170°C.

[0196] In certain embodiments, the product collection temperature of step (d) is 170°C or less, for example, 170°C, 165°C, 160°C, 155°C, 150°C, 145°C, 140°C, 135°C, 130°C, 125°C, 120°C, 115°C, 110°C, 105°C, 100°C, 95°C, 90°C, 85°C, 80°C, 75°C, 70°C, or any value between any two of the above ranges. In certain embodiments, the product collection temperature of step (d) is 80°C to 150°C. In certain embodiments, the product collection temperature of step (d) is 110°C to 140°C.

[0197] In certain embodiments, the quench zone of the reactor is connected to the reaction section of the reactor and has the same internal dimensions as the reactor, but is not jacketed. In certain embodiments, the quench zone of the reactor has a length of 1 to 3 meters (e.g., 1.5 meters, 1.6 meters, 1.7 meters, 1.8 meters, 1.9 meters, 2 meters, 2.1 meters, 2.2 meters, 2.3 meters, 2.4 meters, 2.5 meters, 2.6 meters, 2.7 meters, 2.8 meters, 2.9 meters, 3 meters, or any value between any two of the above values).

[0198] In certain embodiments, in step (d), the temperature of the isocyanate obtained in step (c) is rapidly reduced by utilizing the latent heat of vaporization of the quenching medium. In certain embodiments, the quenching medium is an organic solvent (e.g., toluene, chlorobenzene, chloronaphthalene), isocyanate, or a mixture consisting of a solvent and an isocyanate as a quenching medium to reduce the temperature of the reactor. In certain embodiments, the quenching medium described in step (d) is selected from the group consisting of an organic solvent, an isocyanate, phosgene, hydrogen chloride, an inert carrier gas, and any combination thereof. In certain embodiments, the organic solvent is selected from the group consisting of dichloromethane, chlorobenzene, o-dichlorobenzene, benzene, toluene, xylene, hexane, tetrahydrofuran, chloronaphthalene, and any combination thereof. In certain embodiments, the quenching medium is o-dichlorobenzene.

[0199] In some embodiments, the quenching medium is liquid (for example, liquid phosgene). In some embodiments, the temperature of the isocyanate obtained in step (c) is rapidly reduced by using phosgene or a mixture of phosgene and isocyanate as a quenching medium. Without being limited by any theory, it is believed that the use of phosgene or a mixture of phosgene and isocyanate as a quenching medium is better than the use of an organic solvent as a quenching medium. For example, the use of phosgene or a mixture of phosgene and isocyanate as a quenching medium can avoid the use of an organic solvent in the entire reaction system, and can also avoid the problem of solid wall attachment causing inlet blockage, so that there is no solvent recovery, distillation, and refining cycle in the entire process, and the preparation process is simpler, with lower energy consumption and less cost. At the same time, due to the shortening of the high-temperature refining process, the high-temperature residence time of the reaction product isocyanate is greatly shortened, the self-polymerization reaction is reduced, and the product yield is higher.

[0200] The quenching medium is evenly sprayed in the reactor's quenching zone via a spraying device, ensuring uniform contact with the high-temperature reaction liquid and completing the cooling process, ultimately reducing the temperature to 150-200°C. The spraying device can take various forms, such as multi-directional perforations in the pipeline for uniform distribution, or various types of fluid nozzles. The quenching medium delivery rate is dynamically adjusted based on the temperature of the absorber.

[0201] In another aspect, the present application provides a method for preparing pentamethylene diisocyanate, wherein the method comprises:

[0202] (a) providing a pentamethylenediamine derivative stream and a phosgene stream and mixing them in a material mixing device;

[0203] (b) spraying the mixture obtained in step (a) into the diffusion port of the reactor, and using a baffle disposed in the reactor near the feed end to resist the lateral velocity of the material at the discharge end of the material mixing device;

[0204] (c) The pentamethylenediamine derivative and phosgene in the mixture enter the reaction zone of the reactor and react in the reaction zone to generate pentamethylene diisocyanate.

[0205] In certain embodiments, in the method for preparing pentamethylene diisocyanate provided herein, the method further comprises step (d): collecting the pentamethylene diisocyanate prepared in step (c).

[0206] All contents described in the "Pentamethylenediamine Derivatives" section of this application, as well as all contents described in the above "Step (a)", "Step (b)", "Step (c)", and "Step (d)" sections are also applicable to the description of the method for preparing pentamethylene diisocyanate in this section, and therefore are not repeated here.

[0207] In certain embodiments, the pentamethylenediamine derivative stream in step (a) is purified according to the pentamethylenediamine derivative purification method described herein. In certain embodiments, the pentamethylenediamine derivative stream in step (a) is in a solid state, and the phosgene stream is in a gaseous state. In certain embodiments, no solvent is used in step (a).

[0208] The method for preparing isocyanate provided in this application also has at least the following advantages:

[0209] (1) No solvent (especially, organic solvent) is involved in the entire process, and the solid reactant (i.e., amine salt stream) and the reaction gas (i.e., phosgene stream) are directly contacted and reacted;

[0210] (2) No other solid delivery system is required. The reaction gas is used as the carrier gas / power gas to transport the solids into the reactor. The solid raw materials and the reaction system are not exposed to the outside air.

[0211] (3) The solid material is in a spraying state in the reactor, which provides a speed for the solid material to enter the reactor, so that it is evenly dispersed and fully contacted with the reaction gas;

[0212] (4) There are only reaction gases and reaction solids in the system, the reaction process heat transfer is rapid and uniform, and the reaction is efficient;

[0213] (5) A special-sized annular baffle is added to the inlet of the pipeline reactor to effectively resist the lateral velocity of the solid material after the mixer outlet, preventing the solid material from directly contacting the jacket, and the solid material is not easy to stick to the wall or fail at high temperature;

[0214] (6) It can be produced continuously, with vertical pipelines without back mixing, and the reaction effect is uniform and efficient.

[0215] More specifically, the method for preparing pentamethylene diisocyanate provided in the present application has at least the following advantages:

[0216] (1) Compared with the conventional method of first converting a pentamethylenediamine salt into pentamethylenediamine and then reacting it with phosgene to prepare pentamethylenediisocyanate, the pentamethylenediamine derivative provided by the present invention (particularly a PDA·CO2 covalent compound) can be purified after simple sublimation and desublimation treatment and then directly reacted with phosgene to prepare pentamethylenediisocyanate. The entire reaction process is simple to operate and can be produced continuously.

[0217] (2) In the method for preparing pentamethylene diisocyanate provided by the present invention, the reaction process is relatively gentle, the target product prepared is highly selective, and few by-products are produced.

[0218] (3) Compared with the conventional gas phase reaction method in which the amine stream is vaporized at high temperature and then mixed with an inert carrier gas to form an amine stream and then reacted with a phosgene stream, the method for preparing pentamethylenediamine diisocyanate from pentamethylenediamine derivatives (especially PDA·CO2 covalent compounds) provided by the present invention does not require high temperature vaporization first, nor does it require an inert carrier gas for dispersion. Instead, it directly utilizes solid feed and uses the CO2 generated during the reaction as an inert carrier gas, which not only saves energy consumption, but also greatly reduces the occurrence of side reactions and improves product purity.

[0219] Apparatus for purifying amine salts

[0220] In another aspect, the present application provides an apparatus for purifying amine salts, which is used to perform the method for purifying amine salts according to the present application.

[0221] In certain embodiments, the apparatus for purifying amine salts provided herein comprises a raw material storage tank, a powder absorber, a heater, and a separator, wherein:

[0222] The raw material storage tank is used to store the first mixture containing amine salt, and a first discharge port is provided at the bottom of the raw material storage tank;

[0223] The powder absorber is provided with a first air inlet, a first feed port, and a second discharge port. The first feed port is selectively connected to the first discharge port of the raw material storage tank through a valve, and is selectively connected to the first air inlet and the second discharge port, and negative pressure is formed in the powder absorber; the first air inlet is used to introduce carrier gas into the powder absorber;

[0224] The heater is provided with a second feed port and a third discharge port, and the second feed port is selectively connected to the second discharge port of the powder absorber;

[0225] The separator is provided with a draft tube, a first exhaust port, and a fourth discharge port. The draft tube is spirally arranged along the inner wall of the separator. The first exhaust port is located at the top of the separator for discharging amine salt, amine gas, and byproduct gas. The fourth discharge port is located at the bottom of the separator for discharging solid impurities. In certain embodiments, the valve is a rotary feed valve. In certain embodiments, the heater contains a heating medium. In certain embodiments, the heating medium is selected from the group consisting of an inorganic superconducting heat transfer medium, a composite heat-conducting fiber medium, a graphite heat-conducting medium, a carbon fiber heat-conducting medium, thermal oil, high-pressure steam, or molten salt. In certain embodiments, the heating medium is thermal oil. In certain embodiments, the outer surface of the inner tube of the heater is coated with a heat-conducting metal, such as aluminum, copper, silver, an aluminum alloy, a copper alloy, a silver alloy, etc. In certain embodiments, the separator is provided with a heating device. In certain embodiments, the heating device comprises a heating jacket disposed on the outer wall of the separator and / or a heating tube disposed within the separator.

[0226] The device for purifying amine salts provided by the present application will be further described below with reference to FIG1 and through specific embodiments.

[0227] In a specific embodiment, the present application provides a device for purifying amine salts, as shown in FIG1 , the device includes a raw material storage tank 110 , a powder absorber 120 , a heater 130 and a separator 140 , wherein:

[0228] The raw material storage tank 110 is used to store the first mixture containing amine salt, and a first discharge port 111 is provided at the bottom thereof;

[0229] The powder absorber 120 is provided with a first air inlet 121, a first feed port 122, and a second discharge port 123. The first feed port 122 is selectively connected to the first discharge port 111 of the raw material storage tank 110 via a valve 150, and is selectively connected to the first air inlet 121 and the second discharge port 123, and a negative pressure is formed in the powder absorber 120; the first air inlet 121 is used to introduce a carrier gas into the powder absorber 120;

[0230] The heater 130 is provided with a second feed port 131 and a third discharge port 132 , and the second feed port 131 is selectively connected to the second discharge port 123 of the powder absorber 120 ;

[0231] The separator 140 is provided with a guide tube 141, a first exhaust port 142 and a fourth discharge port 143, wherein the guide tube 141 is spirally arranged along the inner wall of the separator 140; the first exhaust port 142 is arranged at the top of the separator 140 for discharging amine salt, amine gas and by-product gas; the fourth discharge port 143 is arranged at the bottom of the separator 140 for discharging solid impurities.

[0232] In some embodiments, a heating jacket 144 is provided on the exterior of the separator 140. In some embodiments, a heating cartridge 145 is provided inside the separator 140. In some embodiments, the inlet and outlet of the heating cartridge 145 are independently connected to the exterior wall of the separator 140, facilitating flexible control of the temperature of the heating cartridge 145. In some embodiments, a heating medium is provided in the heater 130, the separator 140, and the heating cartridge 145.

[0233] Device for preparing isocyanate

[0234] In another aspect, the present application provides an apparatus for preparing isocyanate, which is used to perform the method for preparing isocyanate according to the present application.

[0235] In certain embodiments, the apparatus for preparing isocyanate provided in the present application is configured by a combination of a solid storage tank, a gas storage tank, a material mixing device, and a pipeline reactor. No solvent is required, and the solid reactant and the reaction gas are directly contacted and reacted; no other solid conveying system is required, and the reaction gas is used as a carrier gas / power gas to transport the solid into the reactor, and the solid raw materials and the reaction system are not exposed to the outside air; the solid material is in a spraying state before passing through the material mixing device and entering the reactor, which provides a speed for the solid material to enter the reactor, so that it is evenly dispersed, fully contacted with the reaction gas, and the reaction is efficient; continuous production is achieved, the vertically placed pipeline reactor has no backmixing, and the reaction effect is uniform and efficient.

[0236] To achieve this goal, this application adopts the following technical solutions:

[0237] The present application provides a device for preparing isocyanate, which includes a solid storage tank, a gas storage tank, a material mixing device and a pipeline reactor, wherein the top of the solid storage tank is provided with a feed port and a first air inlet, the bottom of the solid storage tank is provided with a discharge port, and the discharge port pipeline is connected to the material mixing device; the top of the gas storage tank is provided with a first air outlet, a second air outlet and a second air inlet, the first air outlet and the first air inlet pipeline are connected, and the second air outlet pipeline is connected to the material mixing device, and the material mixing device is used to mix the material transported by the solid storage tank and the gas transported by the gas storage tank; the discharge end of the material mixing device is connected to the feed end of the pipeline reactor, and a circular baffle is provided on the side of the pipeline reactor close to the feed end, and the circular baffle is used to resist the lateral velocity of the material at the discharge end of the material mixing device.

[0238] It should be noted that the pipeline reactor in this application is placed vertically, which solves the problem of back mixing in other reactors, and the reaction effect is uniform and efficient, making it suitable for wide promotion and use.

[0239] As a preferred technical solution of the present application, a third gas inlet is further provided on the top of the solid storage tank, and the third gas inlet is used to input an inert gas. It should be noted that the inert gas in the present application can be nitrogen, argon, etc., and those skilled in the art can make adaptive adjustments according to actual conditions.

[0240] The solid storage tank is also provided with an inspection port on one side near the bottom. It should be noted that the specific size and discharge method of the inspection port are not particularly limited in this application, and those skilled in the art can make adaptive adjustments according to actual conditions.

[0241] As a preferred technical solution of the present application, the discharge port of the solid storage tank is connected to the material mixing device through a solid conveying pipe. The solid conveying part is a solid conveying meter. The solid conveying meter is a powder meter or an online weighing meter. It should be noted that the present application does not specifically limit the specific model, size, material and other characteristics of the powder meter or online weighing meter. It is sufficient that it can meet the requirements of conveying solid materials. Those skilled in the art can make adaptive adjustments based on actual conditions.

[0242] As a preferred technical solution of the present application, at least one solid storage tank is provided, adjacent solid storage tanks are connected by pipelines, and opening and closing parts are provided on the pipelines between adjacent solid storage tanks, and the opening and closing parts are used to control the feeding sequence and feeding amount of the solid storage tanks.

[0243] It should be noted that this application does not impose any particular restrictions on the specific model, size, material, and other characteristics of the solid storage tank, as long as it can meet the storage requirements of the solid material. Those skilled in the art can make adaptive adjustments based on actual conditions. When there are multiple solid storage tanks, such as 2, 3, 4, 5, 6, etc., the middle of each solid storage tank is connected, and the valve at the discharge of the solid storage tank is switched to switch the feed to ensure continuous transportation of the solid material.

[0244] The opening and closing member is a valve. It should be noted that the present application does not impose any special restrictions on the specific model, size, material and other features of the valve, as long as it can meet the control of the solid material conveying state. Those skilled in the art can make adaptive adjustments according to actual conditions.

[0245] As a preferred technical solution of the present application, a gas compressor and a gas flow meter are connected to the second gas outlet of the gas storage tank via pipelines in sequence along the flow of gas. It should be noted that the present application does not impose any particular restrictions on the specific model, size, material, and other characteristics of the gas compressor and gas flow meter, and those skilled in the art may make adaptive adjustments based on actual conditions.

[0246] The gas compressor is used to selectively compress gas, and the gas flowmeter is used to measure the gas delivery flow. As a preferred technical solution of the present application, the gas flowmeter is a velocity flowmeter or a volume flowmeter. The velocity flowmeter is a turbine flowmeter or a vortex flowmeter. It should be noted that the present application does not specifically limit the specific model, size, material and other characteristics of the turbine flowmeter or vortex flowmeter. It is sufficient to detect and control the flow of gas. Those skilled in the art can make adaptive adjustments based on actual conditions.

[0247] The volume flowmeter is a Roots flowmeter. It should be noted that this application does not impose any particular restrictions on the specific model, size, material, and other characteristics of the Roots flowmeter, as long as it can detect and control the volume of the gas. Those skilled in the art can make adaptive adjustments based on actual conditions.

[0248] As a preferred technical solution of the present application, the material mixing device includes a cylinder, and an air inlet end and a feed end are provided on the top of the cylinder. The air inlet end includes a first tapered pipeline, a straight pipeline and a second tapered pipeline arranged in sequence along the direction of the gas, and the feed end feeds to one side of the cylinder body and is arranged near the air outlet end of the second tapered pipeline.

[0249] The bottom of the cylinder is provided with a discharge port, the inner diameter of which gradually decreases along the direction of the material. As a preferred technical solution of the present application, the inner diameter of the first tapered conduit decreases along the direction of the gas. The inner diameters of the second tapered conduits also decrease along the direction of the gas.

[0250] It should be noted that the material mixing device in this application can fully mix the solid-phase material and the gas by designing a specific "Venturi-like form", and the compressed reaction gas passes through the cylinder quickly, the cross-sectional area becomes smaller, the gas flow rate increases, and a negative pressure is formed in the cylinder after the outlet, thereby sucking in the solid material, and then spraying the solid material from the outlet into the pipeline reactor at a certain speed.

[0251] As a preferred technical solution of the present application, the pipeline reactor includes a reactor body, the outer surface of the reactor body is provided with a jacket tube, the bottom end of the reactor body is flush with the bottom end of the jacket tube, and the length of the jacket tube is less than the length of the reactor body.

[0252] It should be noted that the present application does not impose any special restrictions on the specific model, size, material and other characteristics of the jacketed tube, and those skilled in the art may make adaptive adjustments based on actual conditions.

[0253] In this application, the pipeline reactor is vertically arranged, and the length of the jacketed tube is shorter than the length of the reactor body because a heat transfer buffer zone can be reserved to prevent instantaneous high-temperature carbonization of solid materials entering the reaction tube; and from the perspective of design safety, the high-temperature jacketed tube has stress release at high temperatures. Under high temperature conditions, the pipeline is stretched and safety is guaranteed.

[0254] A circular baffle is provided in the reactor body near the feed end, and the circular baffle and the reactor body are coaxially arranged. In this application, a circular baffle is provided in the reactor body near the feed end because the solid material is ejected in a relatively dispersed state. To prevent the material from sticking to the wall, a circular baffle is installed at the injection inlet of the reactor body. The circular baffle needs to be at a certain distance from the reaction tube wall, and the bottom of the circular baffle should be above the edge of the heat exchange jacket so that the temperature of the circular baffle and the temperature of the reaction tube wall have a certain gradient.

[0255] A fixing bar is radially disposed between the feed end face of the reactor body and the annular baffle. The fixing bar is used to secure the pipeline at the feed end within the reactor body. The feed end between the fixing bar and the annular baffle is a fan-shaped feed end, the maximum diameter of which is the same as the diameter of the annular baffle. The fan-shaped feed end is used to prevent material from being ejected and overflowed. It should be noted that this application does not specifically limit the specific model, size, material, and other characteristics of the fixing bar, and those skilled in the art may make adaptive adjustments based on actual circumstances.

[0256] As a preferred technical solution of the present application, the distance between the outer diameter of the annular baffle and the inner wall of the reactor body is 1 to 3 cm, for example, it can be 1 cm, 1.2 cm, 1.4 cm, 1.6 cm, 1.8 cm, 2 cm, 2.2 cm, 2.4 cm, 2.6 cm, 2.8 cm, 3 cm, etc., but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0257] In the present application, the distance between the outer diameter of the annular baffle and the inner wall of the reactor body is 1 to 3 cm because within this size range, the mixed material can be sprayed downward smoothly to avoid carbonization and accumulation of reactants inside the annular ring and on the wall of the reaction tube; if the spacing is too large, the diameter of the entire annular ring is too small, and under high-speed flow, there is lateral acceleration at the edge of the baffle, resulting in umbrella-shaped spraying, and the material is sprayed onto the tube wall, which is prone to high-temperature carbonization. At the same time, there is more space around and above the annular baffle, which makes it easier for carbides to accumulate; if the spacing is too small, the temperature difference between the annular baffle temperature and the reaction tube wall temperature is small, the temperature inside the annular ring is high, and carbonization and accumulation on the inner wall of the annular ring are easy.

[0258] The bottom of the annular baffle is arranged higher than the top of the jacket tube, and the minimum linear distance between the bottom of the annular baffle and the top of the jacket tube is 1 to 2 cm, for example, it can be 1 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm, 2 cm, etc., but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0259] In the present application, the minimum linear distance between the bottom of the annular baffle and the top of the jacket tube is 1 to 2 cm. This is because if the distance is too large, the time it takes for the mixed reactants to pass through the annular baffle to reach the edge of the jacket tube will be prolonged, and the residence time in the reaction tube will increase, which is not conducive to controlling the reaction time; the injection effect of the mixed material will be weakened before it reaches the edge of the jacket tube, and the mixing effect will deteriorate; if the distance is too small, the temperature difference between the annular baffle temperature and the reaction tube wall temperature will be small, the temperature inside the annulus will be high, and carbonization and accumulation on the inner wall of the annulus will be easy.

[0260] Illustratively, the operating method of the apparatus for preparing isocyanate provided in the present application includes:

[0261] The reaction gas is continuously delivered to the gas storage tank, where the gas compressor compresses and increases the pressure. After being measured by the gas flow meter, the gas enters the material mixing device. The solid material is delivered to the material mixing device through the solid storage tank. The solid storage tanks can be made into multiple groups, with the middle of the solid storage tanks connected. The discharge valve of the solid storage tank is switched to switch the feed to ensure the continuous delivery of the solid material.

[0262] Solid materials are conveyed under negative pressure and then measured by a solid conveying meter before entering the material mixing device. The solid conveying meter uses a powder meter, ensuring unobstructed material flow.

[0263] After the reaction gas and solid material are mixed in the material mixing device, they are injected into the pipeline reactor under the influence of high-velocity gas. Because the solid material is dispersed during injection, a circular baffle is installed at the injection inlet of the pipeline reactor to prevent it from sticking to the wall. The baffle should be kept a certain distance from the reaction tube wall, between 1 and 3 cm. The bottom of the baffle should be above the edge of the jacketed tube, with a spacing of 1 to 2 cm. This ensures a certain temperature gradient between the baffle and the reaction tube wall. After the reaction is completed, the material enters the reaction liquid storage tank or transfer tank for the next step.

[0264] The device for preparing isocyanate provided by the present application is further described below with reference to the accompanying drawings and through specific embodiments.

[0265] In a specific embodiment, the present application provides a device for preparing isocyanate, as shown in Figures 2, 3, 4 and 5, the device includes a solid storage tank 1, a gas storage tank 5, a material mixing device 9 and a pipeline reactor, the top of the solid storage tank 1 is provided with a third feed port 2 and a first air inlet, the bottom of the solid storage tank 1 is provided with a discharge port, and the discharge port pipeline is connected to the material mixing device 9; the top of the gas storage tank 5 is provided with a first air outlet, a second air outlet, and a second air inlet 6, the first air outlet and the first air inlet pipeline are connected, and the second air outlet pipeline is connected to the material mixing device 9, the material mixing device 9 is used to mix the material conveyed by the solid storage tank 1 and the gas conveyed by the gas storage tank 5; the discharge end of the material mixing device 9 is connected to the feed end of the pipeline reactor, and a circular baffle 13 is provided on the side of the pipeline reactor close to the feed end, and the circular baffle 13 is used to resist the lateral velocity of the material at the discharge end of the material mixing device 9.

[0266] In the present application, through the combination of a solid storage tank 1, a gas storage tank 5, a material mixing device 9 and a pipeline reactor, no solvent is required, and the solid reactants and the reaction gas are in direct contact and reaction; there is no need to use other solid conveying systems, and the reaction gas is used as a carrier gas / power gas to transport the solids into the reactor, and the solid raw materials and the reaction system are not exposed to the outside air; the solid material is in a spraying state before passing through the material mixing device and entering the reactor, which provides speed for the solid material to enter the reactor, so that it is evenly dispersed, fully in contact with the reaction gas, and the reaction is efficient; continuous production is achieved, the vertically placed pipeline reactor has no backmixing, and the reaction effect is uniform and efficient.

[0267] It should be noted that the pipeline reactor in this application is placed vertically, which solves the problem of back mixing in other reactors, and the reaction effect is uniform and efficient, making it suitable for wide promotion and use.

[0268] The top of the solid storage tank 1 is also provided with a third air inlet 3 for inputting inert gas. It should be noted that the inert gas in this application can be nitrogen, argon, etc., and those skilled in the art can make adaptive adjustments according to actual conditions.

[0269] An inspection port is also provided on one side near the bottom of the solid storage tank 1. It should be noted that the specific size and discharge method of the inspection port are not particularly limited in this application, and those skilled in the art can make adaptive adjustments according to actual conditions.

[0270] The discharge port of the solid storage tank 1 is connected to the material mixing device 9 via a solid conveying member 4. The solid conveying member 4 is a solid conveying meter, which is a powder meter or an online weighing meter. It should be noted that this application does not impose any special restrictions on the specific model, size, material, and other characteristics of the powder meter or online weighing meter. It is sufficient that it can meet the requirements of conveying solid materials. Those skilled in the art can make adaptive adjustments based on actual conditions.

[0271] The solid storage tank 1 is provided with at least one, adjacent solid storage tanks 1 are connected by pipelines, and the pipelines between adjacent solid storage tanks 1 are provided with opening and closing parts, and the opening and closing parts are used to control the feeding sequence and feeding amount of the solid storage tank 1. It should be noted that the present application does not make special restrictions on the specific model, size, material and other characteristics of the solid storage tank 1, as long as it can meet the storage requirements of the solid material, and those skilled in the art can make adaptive adjustments according to actual conditions. When there are multiple solid storage tanks 1, such as 2, 3, 4, 5, 6, etc., the middle of each solid storage tank 1 is connected, and the valve at the discharge of the solid storage tank 1 is switched to switch the feeding to ensure the continuous transportation of the solid material.

[0272] The opening and closing member is a valve. It should be noted that the present application does not impose any special restrictions on the specific model, size, material and other features of the valve, as long as it can meet the control of the solid material conveying state. Those skilled in the art can make adaptive adjustments based on actual conditions.

[0273] A gas compressor 7 and a gas flow meter 8 are connected to the second gas outlet of the gas storage tank 5 in sequence along the gas flow path. The gas compressor 7 is used to selectively compress the gas, and the gas flow meter 8 is used to measure the gas delivery flow rate. It should be noted that this application does not impose any specific restrictions on the specific model, size, material, and other characteristics of the gas compressor 7 and the gas flow meter 8. Those skilled in the art may make adaptive adjustments based on actual circumstances.

[0274] The gas flowmeter 8 is a velocity flowmeter or a volume flowmeter, the velocity flowmeter is a turbine flowmeter or a vortex flowmeter, and the volume flowmeter is a Roots flowmeter. It should be noted that the present application does not specifically limit the specific model, size, material and other features of the turbine flowmeter or vortex flowmeter, as long as it can detect and control the flow rate of the gas, and those skilled in the art can make adaptive adjustments according to actual conditions. It should be noted that the present application does not specifically limit the specific model, size, material and other features of the Roots flowmeter, as long as it can detect and control the volume of the gas, and those skilled in the art can make adaptive adjustments according to actual conditions.

[0275] The material mixing device 9 includes a cylinder, with an air inlet 12 and a feed end disposed at the top of the cylinder. The air inlet 12 includes a first tapered conduit, a straight conduit, and a second tapered conduit, arranged sequentially along the direction of the gas flow. The feed end is disposed on one side of the cylinder, near the air outlet of the second tapered conduit. The bottom of the cylinder is provided with a discharge end, the inner diameter of which gradually decreases along the direction of the material flow. The inner diameter of the first tapered conduit decreases sequentially along the direction of the gas flow. The inner diameter of the second tapered conduit also decreases sequentially along the direction of the gas flow.

[0276] It should be noted that the material mixing device 9 in the present application can fully mix the solid-phase material and the gas by designing a specific "Venturi-like form", and the compressed reaction gas passes through the cylinder quickly, the cross-sectional area becomes smaller, the gas flow rate increases, and a negative pressure is formed in the cylinder after the outlet, thereby sucking in the solid material, and then spraying the solid material from the outlet into the pipeline reactor at a certain speed.

[0277] The pipeline reactor includes a reactor body 10, with a jacket tube 11 sheathed on the outer surface of the reactor body 10. The bottom end of the reactor body 10 is flush with the bottom end of the jacket tube 11, and the length of the jacket tube 11 is shorter than the length of the reactor body 10. It should be noted that the specific model, size, material, and other characteristics of the jacket tube 11 are not particularly limited in this application, and those skilled in the art may make adaptive adjustments based on actual conditions.

[0278] A circular baffle 13 is provided in the reactor body 10 near the feed end, and the circular baffle 13 is coaxially arranged with the reactor body 10. In the present application, the circular baffle 13 is provided in the reactor body 10 near the feed end because the solid material is ejected in a relatively dispersed state. To prevent the material from sticking to the wall, the circular baffle 13 is installed at the injection inlet of the reactor body 10. The circular baffle 13 needs to be at a certain distance from the reaction tube wall, and the bottom end of the circular baffle 13 should be above the edge of the heat exchange jacket so that there is a certain temperature gradient between the circular baffle 13 and the reaction tube wall.

[0279] A fixing bar 15 is radially disposed between the feed end face of the reactor body 10 and the annular baffle 13. This fixing bar 15 is used to secure the feed end piping within the reactor body 10. The feed end between the fixing bar 15 and the annular baffle 13 is a fan-shaped feed end 14. The maximum diameter of the fan-shaped feed end 14 is the same as the diameter of the annular baffle 13. This fan-shaped feed end 14 is used to prevent material from being ejected or spilled. It should be noted that this application does not impose any particular restrictions on the specific model, size, material, and other characteristics of the fixing bar 15. Those skilled in the art may make adaptive adjustments based on actual circumstances.

[0280] The distance between the outer diameter of the annular baffle 13 and the inner wall of the reactor body 10 is 1 to 3 cm, for example, 1 cm, 1.2 cm, 1.4 cm, 1.6 cm, 1.8 cm, 2 cm, 2.2 cm, 2.4 cm, 2.6 cm, 2.8 cm, 3 cm, etc., but is not limited to the values ​​listed above, and other values ​​not listed within this numerical range are also applicable. The bottom of the annular baffle 13 is arranged higher than the top of the jacket tube 11, and the minimum linear distance between the bottom of the annular baffle 13 and the top of the jacket tube 11 is 1 to 2 cm, for example, 1 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm, 2 cm, etc., but is not limited to the values ​​listed above, and other values ​​not listed within this numerical range are also applicable.

[0281] Pentamethylenediamine derivatives

[0282] In another aspect, the present application provides a pentamethylenediamine derivative.

[0283] As used herein, the term "derivative" refers to any compound having the same or similar core structure as a compound (also referred to as a parent compound) but having at least one structural difference, including substitution, deletion, and / or addition of one or more atoms or functional groups. For example, a "pentanediamine derivative" refers to any compound having the same or similar core structure as pentamethylenediamine but having at least one structural difference, including substitution, deletion, and / or addition of one or more atoms or functional groups. A "derivative" may include a deuterated, oxidized, dehydrated, unsaturated, polymer-conjugated, or glycosylated form of the parent compound, or an ester, amide, lactone, homolog, ether, thioether, cyano, amino, alkylamino, sulfhydryl, heterocyclic, fused heterocyclic, polymeric, pegylated, benzylidene, triazolyl, piperazinyl, or deuterated form thereof.

[0284] In certain embodiments, the pentamethylenediamine derivatives provided herein have the same core structure as 1,5-pentamethylenediamine (also known as "cadaverine", PDA). (where * is attached to other atoms), but with extra carbon and oxygen atoms.

[0285] In certain embodiments, the pentamethylenediamine derivatives provided herein are covalent compounds formed by pentamethylenediamine and carbon atoms and oxygen atoms, wherein the molar ratio of pentamethylenediamine to carbon atoms other than carbon atoms in pentamethylenediamine and oxygen atoms per molecule of the pentamethylenediamine derivative is 1:1:2. The molar ratio of each atom in the pentamethylenediamine derivative can be determined by methods known in the art, such as elemental analysis and mass spectrometry.

[0286] In certain embodiments, the pentamethylenediamine derivative provided herein is a derivative of 1,5-pentamethylenediamine. In certain embodiments, the pentamethylenediamine derivative provided herein has a chemical formula of H2N(CH2)5NH2CO2 (also referred to as "PDA·CO2" in this application).

[0287] In certain embodiments, the present application provides a pentamethylenediamine derivative having the chemical formula H2N(CH2)5NH2CO2, wherein the nitrogen atom (N atom) and the carbon atom (C atom) are connected by a covalent bond. As used herein, "covalent bond" refers to a chemical bond involving the sharing of electron pairs between atoms, specifically a stable balance of attractive and repulsive forces between atoms when electrons are shared.

[0288] In certain embodiments, the pentamethylenediamine derivatives provided herein have an amide ester In certain embodiments, the pentamethylenediamine derivatives provided herein comprise a zwitterionic structure with an amide ester structure. In certain embodiments, the pentamethylenediamine derivatives provided herein have the chemical structure shown below: In certain embodiments, the pentamethylenediamine derivative provided herein comprises (5-pentammonium)carbamate (ie, (5-azaniumylpentyl)carbamate).

[0289] In certain embodiments, the pentamethylenediamine derivative provided herein has the chemical structure shown below: In certain embodiments, the pentamethylenediamine derivatives provided herein comprise

[0290] In certain embodiments, the pentamethylenediamine derivatives provided herein exist in the form of a mixture. In certain embodiments, the pentamethylenediamine derivatives provided herein exist in the form of a mixture and include In certain embodiments, the pentamethylenediamine derivatives provided herein exist in the form of a mixture and include In certain embodiments, the pentamethylenediamine derivatives provided herein exist in the form of a mixture and include In certain embodiments, the pentamethylenediamine derivatives provided herein exist in the form of a mixture, comprising and The molar amounts are essentially the same.

[0291] "Substantially the same" means that the difference between two or more values ​​does not exceed ±5% (e.g., no more than ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.1%, etc.). For example, when referring to "substantially the same in molar amount," it means that the difference between the molar amounts does not exceed ±5% (e.g., no more than ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.1%, etc.).

[0292] In certain embodiments, the pentamethylenediamine derivatives provided herein exist in the form of a mixture, comprising and The molar amounts are the same.

[0293] In certain embodiments, the pentamethylenediamine derivative provided herein comprises the following structure: In certain embodiments, the pentamethylenediamine derivatives provided herein are composition.

[0294] In certain embodiments, the pentamethylenediamine derivatives provided herein comprise in The total molar amount of In certain embodiments, the pentamethylenediamine derivatives provided herein comprise in The total molar amount of The molar amounts are the same.

[0295] In certain embodiments, the pentamethylenediamine derivatives provided herein comprise in The molar amounts of The molar amounts are essentially the same.

[0296] In certain embodiments, the pentamethylenediamine derivatives provided herein comprise in The molar amounts of In certain embodiments, the pentamethylenediamine derivatives provided herein comprise And the molar ratio of the three is 2:1:1.

[0297] In certain embodiments, the pentamethylenediamine derivatives provided herein are Composition, of which The molar amounts of In certain embodiments, the pentamethylenediamine derivatives provided herein are composed of The molar ratio of the three is 2:1:1.

[0298] In certain embodiments, the pentamethylenediamine derivatives provided herein do not release carbon dioxide at temperatures above 70°C. In certain embodiments, the pentamethylenediamine derivatives provided herein sublime at temperatures above 70°C (e.g., 70-200°C) to form gaseous pentamethylenediamine derivatives, but do not decompose. In certain embodiments, the pentamethylenediamine derivatives provided herein do not release carbon dioxide at temperatures between 70°C and 200°C (e.g., 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, or any value between any two of the above ranges). In certain embodiments, the pentamethylenediamine derivatives provided herein do not release carbon dioxide at temperatures between 70°C and 140°C. In certain embodiments, the pentamethylenediamine derivatives provided herein have a sublimation temperature of 70°C to 140°C (e.g., 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, or any specific temperature between any two of the above numerical ranges). In certain embodiments, the pentamethylenediamine derivatives provided herein have an increased density and / or hardness after sublimation.

[0299] In certain embodiments, the chemical bonding patterns of the pentamethylenediamine derivatives provided herein differ in deuterated water and other deuterated solvents (e.g., deuterated chloroform, deuterated methanol, etc.). The chemical bonding patterns of the pentamethylenediamine derivatives provided herein in deuterated solvents can be determined using methods commonly used in the art (e.g., nuclear magnetic resonance analysis). The inventors of this application have discovered that when nuclear magnetic resonance analysis of the same sample of the pentamethylenediamine derivatives provided herein is performed using different deuterated solvents, the resulting nuclear magnetic resonance characterization information is different, indicating that the solvent affects the structural changes of the sample.

[0300] In certain embodiments, the NMR analysis spectrum of the pentamethylenediamine derivative provided by the present application after being dissolved in deuterated methanol (CD3OD) is shown in Figure 6. In certain embodiments, the NMR analysis spectrum of the pentamethylenediamine derivative provided by the present application after being dissolved in deuterated water solvent (D2O) is shown in Figure 6.1 The H-NMR analysis spectrum is shown in FIG7. In certain embodiments, the pentamethylenediamine derivative provided by the present application is dissolved in a deuterated water solvent (D2O). 13 C-NMR analysis spectrum is shown in Figure 8. In certain embodiments, the pentamethylenediamine derivatives provided herein are 1 H- 1 H chemical shift correlation spectroscopy ( 1 H- 1 H COSY spectrum) is shown in Figure 9. In certain embodiments, the pentamethylenediamine derivatives provided herein are 1 H- 13 C chemical shift correlation spectroscopy ( 1 H- 13 C COSY spectrum) is shown in Figure 10.

[0301] In certain embodiments, the pentamethylenediamine derivatives provided herein do not contain carbonate ions (CO3 2- In certain embodiments, the pentamethylenediamine derivatives provided herein do not contain bicarbonate ions (HCO3 - In certain embodiments, the pentamethylenediamine derivatives provided herein do not contain carbonate ions (CO3 2- ) and bicarbonate ions (HCO3 - In certain embodiments, the pentamethylenediamine derivative provided herein is a PDA·CO2 covalent compound.

[0302] In certain embodiments, the pentamethylenediamine derivative provided herein is prepared according to the method for purifying an amine salt (eg, a pentamethylenediamine derivative) provided herein.

[0303] The above is a summary of this application, which may contain simplifications, generalizations, and omissions of details. Therefore, those skilled in the art should recognize that this section is illustrative only and is not intended to limit the scope of this application in any way. This summary is neither intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0304] Example

[0305] In order to more fully understand the present invention, the following examples are shown. It should be understood that these examples are for illustrative purposes only and are not to be construed as limiting in any way.

[0306] Example 1: Preparation of crude pentamethylenediamine carbonate

[0307] Example 1.1: 285 g / L lysine bicarbonate, crystallized from ethanol

[0308] An engineered Escherichia coli strain containing lysine decarboxylase was prepared with reference to Molecular Cloning Experimental Guide (3rd Edition) (Science Press) and Li Y. et al., Appl. Microbiol. Biotechnol. 2017, 101, 6015-6021. After fermentation in conventional LB medium, the culture medium was centrifuged (speed 8000 rpm, centrifugation time 10 min) to obtain wet engineered Escherichia coli for later use.

[0309] A 285g / L lysine bicarbonate solution was prepared by adding 200g of 99% lysine to 900ml of water, stirring to dissolve the solution, and then introducing carbon dioxide into the solution until the pH reached 7.1-7.6. The carbon dioxide supply was then stopped. Four grams of wet cells of the engineered Escherichia coli bacteria containing lysine decarboxylase prepared above and 0.02g of pyridoxal phosphate were then added. The reaction was initiated at 37°C. The pH was not controlled during the reaction, and the reaction was terminated for 8 hours. The reaction was terminated when the lysine content, as measured by HPLC, was <0.5% (w / v).

[0310] The reaction solution was passed through a 0.2 μm microfiltration membrane to remove large particle impurities, such as cells, bacterial fragments, aggregates, and floccules. The reaction solution was also passed through a 10 KD ultrafiltration membrane to remove small molecular impurities, such as nucleic acids and nucleic acid fragments in the bacterial culture medium, proteins, culture medium components, and other impurities. The solution was then concentrated under reduced pressure to 321 g, and 750 ml of ethanol was added dropwise to allow low-temperature crystallization at 10° C. The solution was filtered and dried to obtain 208 g of a white solid with a pentamethylenediamine carbonate content of 95.4% and a yield of 92.6%.

[0311] Example 1.2: 570 g / L lysine bicarbonate, ethanol crystallization

[0312] An engineered Escherichia coli strain containing lysine decarboxylase was prepared with reference to Molecular Cloning Experimental Guide (3rd Edition) (Science Press) and Li Y. et al., Appl. Microbiol. Biotechnol. 2017, 101, 6015-6021. After fermentation in conventional LB medium, the culture was centrifuged (8000 rpm, 10 min) to obtain wet engineered Escherichia coli for later use.

[0313] A 570g / L lysine bicarbonate solution was prepared by adding 400g of 99% lysine to 700ml of water, stirring to dissolve the solution, and then introducing carbon dioxide into the solution until the pH reached 7.1-7.6. The carbon dioxide supply was then stopped. 8g of the wet cells of the engineered Escherichia coli bacteria containing lysine decarboxylase prepared above and 0.04g of pyridoxal phosphate were then added. The reaction was initiated at 37°C. The pH was not controlled during the reaction, and the reaction was terminated for 10 hours. The reaction was terminated when the lysine content, as measured by HPLC, was <0.5% (w / v).

[0314] The reaction solution was passed through a 0.2 μm microfiltration membrane to remove large particle impurities, such as cells, bacterial fragments, aggregates, and floccules. The reaction solution was also passed through a 10 KD ultrafiltration membrane to remove small molecular impurities, such as nucleic acids and nucleic acid fragments in the bacterial culture medium, proteins, culture medium components, and other impurities. The solution was then concentrated under reduced pressure to 642 g, and 1500 ml of ethanol was added dropwise to allow low-temperature crystallization at 10° C. The solution was filtered and dried to obtain 417.2 g of a white solid with a pentamethylenediamine carbonate content of 98.0% and a yield of 92.8%.

[0315] Example 1.3: Cell reaction was replaced with disruption solution, and ethanol crystallization was replaced with methanol crystallization

[0316] With reference to Molecular Cloning Experiment Guide (3rd Edition) (Science Press) and Li Y. et al., Appl. Microbiol. Biotechnol. 2017, 101, 6015-6021, an Escherichia coli engineered bacteria strain containing lysine decarboxylase was prepared. After fermentation in conventional LB medium, centrifugation (speed 8000 rpm, centrifugation time 10 min) was performed to obtain wet Escherichia coli engineered bacteria. 40 g of pH 7.0 phosphate buffer was added to 8 g of Escherichia coli engineered bacteria cells. After stirring evenly, the bacteria were crushed by high-pressure homogenization to obtain Escherichia coli engineered bacteria cell lysis liquid for later use.

[0317] A 570g / L lysine bicarbonate solution was prepared by adding 400g of 99% lysine to 700ml of water, stirring to dissolve, then introducing carbon dioxide into the solution until the pH reached 7.1-7.6. The carbon dioxide supply was then stopped. The above-prepared engineered Escherichia coli cell suspension and 0.04g of pyridoxal phosphate were added, and the reaction was initiated at 37°C. The pH was not controlled during the reaction, and the reaction was terminated for 10 hours when the lysine content, as measured by HPLC, was <0.5% (w / v).

[0318] The reaction solution was passed through a 0.2 μm microfiltration membrane to remove large particle impurities, such as cells, bacterial fragments, aggregates, and floccules. The reaction solution was also passed through a 10 KD ultrafiltration membrane to remove small molecular impurities, such as nucleic acids and nucleic acid fragments in the bacterial culture medium, proteins, culture medium components, and other impurities. The solution was then concentrated under reduced pressure to 642 g, and 2000 ml of methanol was added dropwise for low-temperature crystallization at 10° C. The solution was filtered and dried to obtain 401.2 g of a white solid with a pentamethylenediamine carbonate content of 97.7% and a yield of 89.2%.

[0319] Example 1.4: Changing the pH to around 8.0 and using immobilized cells

[0320] Prepare an engineered Escherichia coli strain containing lysine decarboxylase with reference to "Molecular Cloning Experimental Guide (3rd Edition)" (Science Press) and Li Y. et al., Appl. Microbiol. Biotechnol. 2017, 101, 6015-6021. Ferment in conventional LB medium and centrifuge (8000 rpm, 10 min) to obtain wet E. coli engineered bacteria for later use. Prepare 80 ml of a mixed solution of 8% polyvinyl alcohol and 2.5% sodium alginate, add 8 g of E. coli cells, mix thoroughly, and then use a peristaltic pump to drip from a height of 10 cm into a cross-linker containing 2% calcium chloride and 3% boric acid. Curing for 8 hours, filter, and rinse repeatedly with distilled water 3-4 times to immobilize the cells for later use.

[0321] A 570 g / L lysine bicarbonate solution was prepared by adding 400 g of lysine (99%) to 700 ml of water, stirring to dissolve, then introducing carbon dioxide into the solution until the pH reached 8.0-8.1. The carbon dioxide supply was then stopped. The immobilized cells and 0.04 g of pyridoxal phosphate were then added, and the reaction was initiated at 37°C. The pH was not controlled during the reaction, and the reaction was terminated for 10 hours when the lysine content, as determined by HPLC, was <0.5% (w / v).

[0322] The reaction solution was passed through a 0.2 μm microfiltration membrane to remove large particle impurities, such as cells, bacterial fragments, aggregates, and floccules. The reaction solution was also passed through a 10 KD ultrafiltration membrane to remove small molecular impurities, such as nucleic acids and nucleic acid fragments in the bacterial culture medium, proteins, culture medium components, and other impurities. The solution was then concentrated under reduced pressure to 642 g, and 1500 ml of ethanol was added dropwise to allow low-temperature crystallization at 10° C. The solution was filtered and dried to obtain 370.7 g of a white solid with a pentamethylenediamine carbonate content of 96.6% and a yield of 82.5%.

[0323] Example 1.5: Vacuum drying instead of methanol, ethanol, and isopropanol crystallization

[0324] An engineered Escherichia coli strain containing lysine decarboxylase was prepared with reference to Molecular Cloning Experimental Guide (3rd Edition) (Science Press) and Li Y. et al., Appl. Microbiol. Biotechnol. 2017, 101, 6015-6021. After fermentation in conventional LB medium, the culture medium was centrifuged (speed 8000 rpm, centrifugation time 10 min) to obtain wet engineered Escherichia coli for later use.

[0325] A 570g / L lysine bicarbonate solution was prepared by adding 400g of 99% lysine to 700ml of water, stirring to dissolve the solution, and then introducing carbon dioxide into the solution until the pH reached 7.1-7.6. The carbon dioxide supply was then stopped. 8g of the wet cells of the engineered Escherichia coli bacteria containing lysine decarboxylase prepared above and 0.04g of pyridoxal phosphate were then added. The reaction was initiated at 37°C. The pH was not controlled during the reaction, and the reaction was terminated for 10 hours. The reaction was terminated when the lysine content, as measured by HPLC, was <0.5% (w / v).

[0326] The reaction solution was passed through a 0.2 μm microfiltration membrane to remove large particle impurities, such as cells, bacterial fragments, aggregates, and floccules. The reaction solution was also passed through a 10 KD ultrafiltration membrane to remove small molecular impurities, such as nucleic acids and nucleic acid fragments in the bacterial culture medium, proteins, culture medium components, and other impurities. The solution was then concentrated under reduced pressure to 642 g and directly dried in a vacuum oven at 50-70° C. to obtain 439.4 g of a white solid with a pentamethylenediamine carbonate content of 97.3% and a yield of 93.8%.

[0327] Example 1.6: Crystallization of Isopropyl Alcohol

[0328] An engineered Escherichia coli strain containing lysine decarboxylase was prepared with reference to Molecular Cloning Experimental Guide (3rd Edition) (Science Press) and Li Y. et al., Appl. Microbiol. Biotechnol. 2017, 101, 6015-6021. After fermentation in conventional LB medium, centrifugation (speed 8000 rpm, centrifugation time 10 min) was performed to obtain wet engineered Escherichia coli for later use.

[0329] A 570g / L lysine bicarbonate solution was prepared by adding 400g of 99% lysine to 700ml of water, stirring to dissolve the solution, and then introducing carbon dioxide into the solution until the pH reached 7.1-7.6. The carbon dioxide supply was then stopped. 8g of the wet cells of the engineered Escherichia coli bacteria containing lysine decarboxylase prepared above and 0.04g of pyridoxal phosphate were then added. The reaction was initiated at 37°C. The pH was not controlled during the reaction, and the reaction was terminated for 10 hours. The reaction was terminated when the lysine content, as measured by HPLC, was <0.5% (w / v).

[0330] The reaction solution was passed through a 0.2 μm microfiltration membrane to remove large particle impurities, such as cells, bacterial fragments, aggregates, and floccules. The reaction solution was also passed through a 10 KD ultrafiltration membrane to remove small molecular impurities, such as nucleic acids and nucleic acid fragments in the bacterial culture medium, proteins, culture medium components, and other impurities. The solution was then concentrated under reduced pressure to 642 g. 2000 ml of isopropanol was added dropwise and crystallized at 10° C. The solution was filtered and dried to obtain 420.5 g of a white solid with a pentamethylenediamine carbonate content of 98.5% and a yield of 93.6%.

[0331] Example 2: Purification of crude pentamethylenediamine carbonate

[0332] Example 2.1: Purification of crude pentamethylenediamine carbonate using the method of the present invention (the amount of carrier gas is 0.4m 3 / h, the inner diameter of the delivery pipe is about 3mm, and the outlet temperature of the heater is 120℃)

[0333] The crude pentamethylenediamine carbonate (2 kg / h) prepared in Example 1.5 was treated using the purification apparatus shown in FIG1 . The amount of CO2 required was 0.4 m 3 / h, the selected conveying pipeline has an inner diameter of about 3 mm, the outlet temperature of the heater 130 is 120°C, the equipment manufacturing cost of this device is about 12,000 yuan, the carrier gas is the by-product CO2 generated by the device, the heating energy consumption of the device is about 0.5 kW, the purity of pentamethylenediamine carbonate is increased from 97.3% before treatment to 99.8%, and the pentamethylenediamine content in the solid slag is 0.034%.

[0334] Comparative Example 2.2: Purification of crude pentamethylenediamine carbonate using a purification apparatus without a heater

[0335] The crude pentamethylenediamine carbonate (2 kg / h) prepared in Example 1.5 was treated using a purification apparatus without heater 130. The amount of CO2 required was 0.4 m 3 / h, the inner diameter of the selected delivery pipeline is about 3 mm, the temperature in the separator 140 is set to 120°C, the equipment manufacturing cost of this device is about 10,000 yuan, the carrier gas is CO2 produced as a by-product of the device, the heating energy consumption of the device is about 0.8 kW, the yield of pentamethylenediamine carbonate is about 60%, and the content of pentamethylenediamine in the solid residue is 92.17%.

[0336] Comparative Example 2.3: Purification of crude pentamethylenediamine carbonate using the method of the present invention (the amount of carrier gas is 0.4m 3 / h, the inner diameter of the delivery pipe is about 3mm, and the outlet temperature of the heater is 100℃)

[0337] The crude pentamethylenediamine carbonate (2 kg / h) prepared in Example 1.5 was treated using the purification apparatus shown in FIG1 . The amount of CO2 required was 0.4 m3 / h, the inner diameter of the selected delivery pipeline was about 3 mm, the outlet temperature of the heater 130 was 100°C, the equipment manufacturing cost of this device was about 12,000 yuan, the carrier gas was CO2 produced as a by-product of the device, the heating energy consumption of the device was about 0.68 kW, and the purity of the pentamethylenediamine carbonate obtained after purification was equivalent to that of Example 2.1, but the yield of pentamethylenediamine carbonate was reduced by 13%, and the pentamethylenediamine content in the solid residue was 1.58%.

[0338] Comparative Example 2.4: Purification of crude pentamethylenediamine carbonate using the method of the present invention (the amount of carrier gas is 0.3m 3 / h, the inner diameter of the delivery pipe is about 3mm, and the outlet temperature of the heater is 120℃)

[0339] The crude pentamethylenediamine carbonate (2 kg / h) prepared in Example 1.5 was treated using the purification apparatus shown in FIG1 . The amount of CO2 required was 0.3 m 3 / h, the inner diameter of the selected delivery pipeline is about 3mm, the outlet temperature of the heater 130 is 120℃, the equipment manufacturing cost of this device is about 12,000 yuan, and the carrier gas is the by-product CO2 produced by the device. As a result, the inner diameter of the delivery pipeline is blocked and the experiment cannot be carried out.

[0340] Comparative Example 2.5: Purification of crude pentamethylenediamine carbonate using the method of the present invention (the amount of carrier gas is 0.4m 3 / h, the inner diameter of the delivery pipe is about >3.8mm or <2mm, and the outlet temperature of the heater is 120℃)

[0341] The crude pentamethylenediamine carbonate (2 kg / h) prepared in Example 1.5 was treated using the purification apparatus shown in FIG1 . The amount of CO2 required was 0.4 m 3 / h, when the inner diameter of the selected delivery pipeline is greater than 3.8mm or less than 2mm, and the outlet temperature of the heater 130 is 120℃, the equipment manufacturing cost of this device is about 12,000 yuan, and the carrier gas is the by-product CO2 produced by the device. As a result, the inner diameter of the delivery pipeline is blocked and the experiment cannot be carried out.

[0342] Comparative Example 2.6: Purification of crude pentamethylenediamine carbonate using a flash chamber purifier with a stirring paddle and scraper attachment

[0343] The crude pentamethylenediamine carbonate prepared in Example 1.5 was treated with an alkaline solution of NaOH to obtain an aqueous solution of pentamethylenediamine. A flash chamber purifier equipped with a stirring paddle and scraper attachment was used to process 2 kg / h of the aqueous solution of pentamethylenediamine after the alkaline treatment. The equipment cost was approximately 52,000 yuan, and the heating energy consumption was approximately 0.7 kW. However, the subsequent separation of pentamethylenediamine and water required an energy consumption of approximately 0.5 kW. The final pentamethylenediamine purity was 99.4%. The pentamethylenediamine content in the solid residue at the bottom of the flash chamber was 1.24%, requiring further treatment to recover the by-product salt. Damage to moving components such as the stirring paddle was not considered at this time.

[0344] Comparative Example 2.7: Purification of crude pentamethylenediamine carbonate using a high vacuum rotary apparatus

[0345] The crude pentamethylenediamine carbonate prepared in Example 1.5 was treated with an alkaline solution of NaOH to obtain an aqueous solution of pentamethylenediamine. The aqueous solution of pentamethylenediamine, freed with alkaline substances, and impurities such as salts were passed through a high-vacuum rotating apparatus to purify the pentamethylenediamine. The apparatus processed 2 kg / h of pentamethylenediamine aqueous solution. The equipment cost was approximately 96,000 yuan, and the heating energy consumption was approximately 0.5 kW. However, subsequent separation of pentamethylenediamine and water also consumed approximately 0.5 kW of energy. The final pentamethylenediamine purity was 99.7%. The pentamethylenediamine content in the solid residue at the bottom of the high-vacuum rotating apparatus was 0.16%. Further treatment of the solid residue was required to recover the by-product salts, and damage to the agitator blades was not considered at this time.

[0346] Example 3: Preparation of pentamethylene diisocyanate

[0347] Example 3.1: Preparation of pentamethylenediamine carbonate using 99.79% purity and phosgene as carrier gas through a mixing device

[0348] The pentamethylenediamine carbonate gas purified in Example 2.1 was desublimed to obtain pentamethylenediamine carbonate particles with a particle size of 20 μm. The pentamethylenediamine carbonate particles were then added to the pentamethylenediamine carbonate solid storage tank 1 via the third feed port 2 using a mechanical conveyor. The third feed port 2 was closed, and nitrogen was introduced through the third gas inlet 3 for displacement. A powder meter was used as the solid delivery meter at the solid material outlet.

[0349] The gas storage tank 5 is a temporary buffer tank for phosgene. Phosgene continuously enters the gas storage tank 5 through the second gas inlet 6. The pressure of the gas storage tank 5 is maintained at 0.06 MPa.

[0350] The gas compressor 7 is turned on to increase the pressure of the phosgene in the gas storage tank 5 to 0.3 MPa, and the phosgene enters the material mixing device 9 after passing through the gas flow meter 8.

[0351] Adjust the front valve of the solid delivery meter to control the gas-solid molar ratio at 1:8, the solid delivery rate at 1 kg / h, and the phosgene delivery rate at 4.5 kg / h.

[0352] The tubular reactor uses a DN100 316L unwelded one-piece steel pipe, and the jacket tube 11 uses a DMN150 316L steel pipe, wherein the top edge of the jacket tube 11 is 20 cm away from the top valve of the reactor body 10; the reactor body 10 uses a DN20 316L stainless steel pipe, and the reactor body 10 is welded with a fan-shaped feed end 14 and a circular baffle 13 on the side close to the feed end. The vertical height of the circular baffle 13 is 4 cm, the inner diameter of the circular baffle 13 is 6 cm, the height of the reactor body 10 is 10 m, and the bottom outlet of the reactor body 10 is connected to the reaction liquid storage tank.

[0353] The heat medium in the jacket tube 11 is molten salt, and the heating temperature is 360°C.

[0354] After passing through the material mixing device 9, the mixed material is sprayed onto the fan-shaped feed end 14 of the reactor body 10. After passing through the annular baffle 13 to converge the solid spray state, it vertically downwards into the reaction zone. In the reaction zone, pentamethylenediamine carbonate and phosgene fully contact and react to produce a PDI reaction liquid, which falls into the reaction liquid storage tank. The reaction liquid storage tank can be added with solvent or a mixture of PDI and solvent to receive it.

[0355] The high-temperature reaction liquid drips from the reaction tube into the reaction liquid receiving tank connected to the reaction tube. Solvent o-dichlorobenzene is added to the storage tank, and the solvent is transported from the bottom of the reaction liquid receiving tank to the quenching section through a circulation pump.

[0356] The quenching section connects to the reaction section, with internal dimensions identical to the reaction tube, but without a jacket. The quenching section is 1.5 meters long. Solvent is evenly sprayed through a spraying device in the quenching section, ensuring uniform contact with the high-temperature reaction liquid, completing the cooling process and ultimately lowering the temperature to 150-200°C. The solvent delivery rate is dynamically adjusted based on the temperature of the absorber.

[0357] The absorption kettle adopts a 100L horizontal storage tank made of 304 or 316 stainless steel, which pre-stores 50L of solvent.

[0358] When the PDI concentration in the receiving kettle reaches 20%, it is subjected to reduced pressure distillation and refined product. The PDI purity is 99.5% after testing. Based on the feed amount, the yield is 95.2%.

[0359] Comparative Example 3.2: Pentamethylenediamine carbonate with a purity of 95.4% was used, phosgene was used as a carrier, and pentamethylenediisocyanate was prepared after a mixing device.

[0360] The experimental setup was identical to that in Example 3.1, and with the same process parameters, the experiment proceeded normally. After the PDI concentration in the receiving kettle reached 20%, the product was purified and tested to have a PDI purity of 98.3%. Based on the feed volume, the yield was 74.6%. During the vacuum distillation process, a significant amount of black solid residue formed at the bottom of the kettle. After multiple experiments, disassembly of the reactor revealed a significant amount of black carbides attached to the edge of the annular baffle behind the mixer.

[0361] Comparative Example 3.3: Preparation of pentamethylenediamine carbonate using 99.79% purity and phosgene as carrier gas, directly fed into the reactor without a mixing device

[0362] Compared with Example 3.1, the reactor specifications are consistent. The material mixing device 9 at the top of the reactor and the annular baffle 13 inside the reactor are removed. The top of the reactor is modified, and the material inlet is divided into two routes, one for pentamethylenediamine carbonate and the other for gaseous phosgene. Pentamethylenediamine carbonate particles with a particle size of 20 μm are conveyed through a mechanical conveying device through a powder conveying meter, and the conveying rate is controlled at 1 kg / h. Phosgene is still conveyed by pressurized conveying at a conveying rate of 4.5 kg / h. In early experiments, the pentamethylenediamine carbonate conveying line at the top of the reactor was repeatedly blocked in the solid material conveying pipeline. Phosgene backflowed into the pentamethylenediamine carbonate pipeline and reacted to form solids, causing blockage. The pentamethylenediamine carbonate conveying line was enlarged to improve the blockage phenomenon, and the experiment was able to proceed. After purification, the final product was tested: the PDI purity was 93.7%; based on the feed amount, the yield was 54.2%. When the reactor was disassembled, it was found that there were a lot of carbides on the side walls of the reactor, pentamethylenediamine carbonate was unevenly dispersed, and the contact with phosgene was insufficient, resulting in a large increase in solidified materials. These were the main reasons for the low yield.

[0363] Example 4: Preparation of crude pentamethylenediamine derivatives

[0364] The Escherichia coli engineered bacteria containing lysine decarboxylase were cultured in a 15 L fermenter for 30 hours, and then centrifuged in a high-speed centrifuge at a speed of 8000 rpm for 10 minutes to obtain wet Escherichia coli engineered bacteria, which were collected for later use.

[0365] A 600g / L lysine carbonate (bicarbonate) solution was prepared by adding 420g of 99% lysine to 680ml of water, stirring to dissolve the solution, and then introducing carbon dioxide until the pH reached 7.1-7.6. The carbon dioxide supply was then stopped. 9g of wet cells of the engineered Escherichia coli bacteria containing lysine decarboxylase prepared above and 0.05g of pyridoxal phosphate were then added. The reaction was initiated at 37°C. The pH was not controlled during the reaction, and the reaction was terminated after 10 hours of reaction. The lysine content, as measured by HPLC, was <0.5% (w / v).

[0366] The reaction solution was passed through a 0.2 μm ceramic membrane to remove large particle impurities, such as bacteria and bacterial fragments, and through a 10 KD ultrafiltration membrane to remove small molecular impurities, such as nucleic acids and nucleic acid fragments, amino acids, proteins, and other impurities in the fermentation broth. The solution was then concentrated under reduced pressure to 680 g and directly dried in a vacuum oven at 50-70° C. to obtain 467.3 g of a white solid with a pentamethylenediamine derivative content of 98.1% and a yield of 94.7%.

[0367] Example 5: Purification and structure confirmation of compounds

[0368] purification

[0369] First, the inventors purified the crude pentamethylenediamine derivative prepared in Example 4. Specifically, the white solid prepared in Example 4 was heated and stirred at 70-140°C in a sealed container, causing gradual sublimation. The sublimated gaseous material was transported through a heated pipeline. The resulting gaseous material was then desublimated in a pipeline at a temperature below 80°C, yielding a pure white, dense solid. The purity of the pentamethylenediamine derivative was increased from 98.1% before treatment to 99.9%, with a yield of 97.2%.

[0370] During the aforementioned experiments, the inventors discovered that, unlike other amines that absorb CO₂ and then decompose upon heating, releasing the absorbed CO₂, the pentamethylenediamine derivative prepared in Example 4 of the present application forms a stable compound that does not release CO₂ upon heating but instead sublimes in a 1:1 ratio. The elemental analysis of the sublimated material is consistent with that of the pre-sublimation material, but the density (compactness) and hardness of the sublimated material increase.

[0371] Structure confirmation

[0372] (1) Elemental analysis

[0373] The elemental analysis of the pentamethylenediamine derivative prepared in Example 4 before and after sublimation was conducted to study its composition. It was found that its elemental composition was approximately C a H b N2O c , the elemental composition analysis is as follows:

[0374] The molecular weight of the sample can be inferred from the fixed composition of two nitrogen atoms in the sample and the nitrogen content obtained from elemental analysis. The number of carbon / hydrogen atoms can be inferred from the sample molecular weight combined with the carbon / hydrogen content. The oxygen content has not been determined, but the number of oxygen atoms can be inferred from the ratio of the content of each element.

[0375] As shown above, the elemental composition of the sample is C6H 14N2O2, expressed as H2N(CH2)5NH2·CO2 or PDA·CO2.

[0376] (2) NMR analysis

[0377] The same PDA·CO2 sample was analyzed by NMR using different deuterated solvents, and different NMR characterization information was found. The NMR analysis spectrum after dissolving in deuterated methanol is shown in Figure 6. The pentamethylenediamine derivative obtained by sublimation and desublimation treatment in Example 5 was subjected to one-dimensional NMR analysis using deuterated water solvent ( 1 H-NMR analysis, 13 C-NMR analysis) and 2D NMR analysis ( 1 H- 1 H COSY and 1 H- 13 C COSY), and the obtained NMR analysis spectra are shown in Figures 7, 8, 9 and 10 respectively.

[0378] After preliminary analysis, the inventors believe that the pentamethylenediamine derivative obtained by sublimation and desublimation in Example 5 is not carbonate (CO3 2- ) or bicarbonate (HCO3 - ) ionic bond form, but a covalent compound that tends to be PDA and CO2. The pentamethylenediamine derivative solution obtained in Example 4, after undergoing the concentration and drying process, is not a traditional PDA carbonate containing ionic bonds, but a PDA·CO2 covalent compound in the form of a mixture.

[0379] According to existing reports (Ciftja, AF; Hartono, A.; Svendsen, F. “Carbamate Formation in Aqueous-Diamine-CO2 Systems” Energy Procedia, 2013, 37, 1605) and the spectra of Figures 7, 8, 9 and 10, the pentamethylenediamine derivative obtained by sublimation and desublimation in Example 5 is a mixture mainly including the following three structures: The molar ratio of the three is 2:1:1.

[0380] The inventors also performed elemental analysis and nuclear magnetic resonance analysis on the pentamethylenediamine carbonate obtained by sublimation in Example 2.1 using similar methods. They found that the pentamethylenediamine carbonate obtained by sublimation in Example 2.1 was not a traditional pentamethylenediamine carbonate containing ionic bonds, but rather a mixture of PDA·CO2 covalent compounds, mainly including the following three structures: The molar ratio of the three is 2:1:1.

[0381] Example 6: Preparation of pentamethylene diisocyanate

[0382] The solid pentamethylenediamine derivative obtained after sublimation and desublimation in Example 5 was added to the pentamethylenediamine derivative solid storage tank 1 via the third feed port 2 using a mechanical conveyor. The third feed port 2 was closed, and nitrogen was introduced through the third gas inlet 3 for displacement. A powder meter was used as the solid material delivery meter at the solid material outlet.

[0383] The gas storage tank 5 is a temporary buffer tank for phosgene. Phosgene continuously enters the gas storage tank 5 through the second gas inlet 6. The pressure of the gas storage tank 5 is maintained at 0.06 MPa.

[0384] The gas compressor 7 is turned on to increase the pressure of the phosgene in the gas storage tank 5 to 0.3 MPa, and the phosgene enters the material mixing device 9 after passing through the gas flow meter 8.

[0385] Adjust the front valve of the solid delivery meter to control the gas-solid molar ratio at 1:8, the solid delivery rate at 1 kg / h, and the phosgene delivery rate at 4.5 kg / h.

[0386] The tubular reactor uses a DN100 316L unwelded one-piece steel pipe, and the jacket tube 11 uses a DMN150 316L steel pipe, wherein the top edge of the jacket tube 11 is 20 cm away from the top valve of the reactor body 10; the reactor body 10 uses a DN20 316L stainless steel pipe, and the reactor body 10 is welded with a fan-shaped feed end 14 and a circular baffle 13 on the side close to the feed end. The vertical height of the circular baffle 13 is 4 cm, the inner diameter of the circular baffle 13 is 6 cm, the height of the reactor body 10 is 10 m, and the bottom outlet of the reactor body 10 is connected to the reaction liquid storage tank.

[0387] The heat medium in the jacket tube 11 is molten salt, and the heating temperature is 360°C.

[0388] After passing through the material mixing device 9, the mixed material is sprayed onto the fan-shaped feed end 14 of the reactor body 10. After passing through the annular baffle 13 to converge the solid spray state, it vertically downwards into the reaction zone. In the reaction zone, the pentamethylenediamine derivative and phosgene fully contact and react to produce a PDI reaction liquid, which falls into the reaction liquid storage tank. The reaction liquid storage tank can be added with solvent or a mixture of PDI and solvent to receive it.

[0389] The high-temperature reaction liquid drips from the reaction tube into the reaction liquid receiving tank connected to the reaction tube. Solvent o-dichlorobenzene is added to the storage tank, and the solvent is transported from the bottom of the reaction liquid receiving tank to the quenching section through a circulation pump.

[0390] The quenching section connects to the reaction section, with internal dimensions identical to the reaction tube, but without a jacket. The quenching section is 1.5 meters long. Solvent is evenly sprayed through a spraying device in the quenching section, ensuring uniform contact with the high-temperature reaction liquid, completing the cooling process and ultimately lowering the temperature to 150-200°C. The solvent delivery rate is dynamically adjusted based on the temperature of the absorber.

[0391] The absorption kettle adopts a 100L horizontal storage tank made of 304 or 316 stainless steel, which pre-stores 50L of solvent.

[0392] When the PDI concentration in the receiving kettle reaches 20%, it is subjected to reduced pressure distillation and refined product. The PDI purity is 99.9%; the yield is 96.1% calculated based on the feed amount.

Claims

1. A method for purifying an amine salt, wherein the method comprises heating a first mixture containing an amine salt to a sublimation temperature of the amine salt to obtain a gaseous amine salt.

2. The method according to claim 1, wherein the heating temperature is controlled to be a temperature at which the amine salt sublimes but does not decompose.

3. The method according to claim 1 or 2, wherein the heating temperature is 70 to 140°C.

4. The method according to claim 1, wherein the method comprises: (1) mixing the first mixture containing the amine salt with a carrier gas to obtain a second mixture; (2) preheating the second mixture obtained in step (1) in a heater so that the outlet temperature of the heater is close to or equal to the sublimation temperature of the amine salt; and (3) Separating the amine salt preheated in step (2) at the sublimation temperature of the amine salt.

5. The method according to claim 4, wherein at least a portion of the carrier gas in step (1) comes from by-product gas of the reaction system.

6. The method according to claim 4 or 5, wherein the carrier gas described in step (1) is compressed to 0.2-0.6 MPa and introduced into a powder absorber to form a negative pressure zone in the powder absorber. The method according to claim 6 , wherein the powder absorber is in the form of a Venturi.

8. The method according to claim 6 or 7, wherein the first mixture described in step (1) is mixed with the carrier gas in the negative pressure area of ​​the powder absorber to obtain the second mixture.

9. The method according to any one of claims 4 to 8, wherein the flow rate of the carrier gas is 0.1 to 1 m 3 / h.

10. The method according to any one of claims 4 to 9, wherein the first mixture in step (1) is in powder form.

11. The method according to any one of claims 4 to 10, wherein the first mixture in step (1) flows into the powder absorber through a rotary feeding valve under the action of gravity.

12. The method according to claim 11, wherein the amount of the first mixture delivered to the powder absorber is controlled by the rotary feeding valve.

13. The method according to claim 11 or 12, wherein the delivery amount of the first mixture to the powder absorber is controlled to be 1-5 kg / h by the rotary feeding valve.

14. The method according to any one of claims 11 to 13, wherein the rotary feeding valve is connected to the powder sucker via a conveying pipeline.

15. The method according to claim 14, wherein the inner diameter of the delivery pipe is 1 to 10 mm.

16. The method according to any one of claims 4 to 15, wherein the mixing in step (1) is carried out at room temperature. The method according to claim 16 , wherein the normal temperature is in the range of -10° C. to 40° C.

18. The method according to any one of claims 4 to 17, wherein in step (2), the heating temperature is controlled so that the heater outlet temperature is a temperature at which the amine salt sublimes but does not decompose.

19. The method according to any one of claims 4 to 18, wherein in step (2), the second mixture obtained in step (1) is heated to 70-140°C.

20. The method according to any one of claims 4 to 19, wherein the heating in step (2) is performed in a heater having a heating medium. The method according to claim 20 , wherein the heating medium is thermal oil.

22. The method according to any one of claims 4 to 21, wherein the outer surface of the inner tube of the heater is coated with a thermally conductive metal.

23. The method according to any one of claims 4 to 22, wherein step (3) comprises flash subliming the preheated amine salt obtained in step (2) in a separator to form a gaseous amine salt.

24. The method according to claim 23, wherein step (3) comprises subjecting the preheated amine salt obtained in step (2) to a swirling motion along a guide tube in the separator, so that at least a portion of the gaseous amine salt is separated from the solid impurities.

25. The method according to claim 24, wherein the gaseous amine salt is discharged through the exhaust port at the upper end of the separator, and the solid impurities are discharged from the discharge port at the lower end of the separator.

26. The method according to any one of the preceding claims, wherein the method does not include the step of alkalizing the first mixture comprising an amine salt using an alkaline substance.

27. The method according to claim 26, wherein the alkaline substance is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonia water, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, and any combination thereof.

28. A method according to any one of the preceding claims, characterised in that The amine salt has a structural formula of R(NH2) n The amine salt form of the free amine of wherein n is 1, 2 or 3 and R is an aliphatic or aromatic hydrocarbon group.

29. The method according to claim 28, characterized in that n is 2, and R is an aliphatic hydrocarbon group.

30. The method according to claim 28, characterized in that n is 2, and R is an aliphatic hydrocarbon group having 2 to 10 carbon atoms.

31. The method according to claim 28, characterized in that n is 2, and R is a linear or cyclic aliphatic hydrocarbon group having 3 to 10 carbon atoms.

32. A method according to any one of the preceding claims, characterised in that The amine salt is selected from the group consisting of hydrochloride, sulfate, bisulfate, nitrate and carbonate.

33. A method according to any one of the preceding claims, characterised in that The amine salt is selected from one or more of the following groups: ethylamine salt, butylamine salt, pentamethylenediamine salt, hexamethylenediamine salt, 1,4-diaminobutane salt, 1,8-diaminooctane salt, aniline salt, p-phenylenediamine salt, m-phenylenediamine salt, toluenediamine salt, 1,5-naphthalenediamine salt, diphenylmethanediamine salt, dicyclohexylmethanediamine salt, m-cyclohexyldimethylenediamine salt, isophoronediamine salt, methylcyclohexanediamine salt, and trans-1,4-cyclohexanediamine salt.

34. The method according to any one of the preceding claims, wherein the amine salt is selected from the group consisting of pentamethylenediamine carbonate, hexamethylenediamine carbonate, isophoronediamine carbonate, methylcyclohexanediamine carbonate.

35. The method of any one of the preceding claims, wherein the amine salt is pentamethylenediamine carbonate.

36. The method of any one of the preceding claims, wherein the amine salt is 1,5-pentanediamine carbonate.

37. A method according to any one of the preceding claims, wherein the amine salt is pentamethylenediamine carbonate and the carrier gas is carbon dioxide.

38. The method according to any one of the preceding claims, wherein the first mixture comprising an amine salt is prepared by introducing carbon dioxide into lysine to form lysine carbonate (bi) salt, and then reacting the lysine carbonate (bi) salt with lysine decarboxylase to generate pentamethylenediamine carbonate.

39. A method for preparing an isocyanate, wherein the method comprises: (a) providing an amine salt stream and a phosgene stream and mixing them in a material mixing device; (b) spraying the mixture obtained in step (a) to the diffusion port of the reactor, and resisting the lateral velocity of the material at the discharge end of the material mixing device through a baffle disposed in the reactor near the feed end; (c) the amine salt and phosgene in the mixture enter the reaction zone of the reactor and are reacted in the reaction zone Reaction to form isocyanate.

40. The method for preparing isocyanate according to claim 39, wherein the method further comprises the following steps: (d) collecting the isocyanate prepared in step (c).

41. The method according to claim 39, wherein the amine salt stream in step (a) is purified according to the method according to any one of claims 1 to 35.

42. The method according to any one of claims 39 to 41, wherein the amine salt stream in step (a) is in a solid state and the phosgene stream is in a gaseous state.

43. The method of any one of claims 39 to 42, wherein the amine salt is pentamethylenediamine carbonate and the isocyanate is pentamethylenediisocyanate.

44. A process according to any one of claims 39 to 43, wherein no solvent is used in step (a).

45. An apparatus for purifying an amine salt according to the method of any one of claims 1 to 38, characterized in that The device comprises a raw material storage tank, a powder absorber, a heater and a separator, wherein: The raw material storage tank is used to store a first mixture containing amine salts, and a first discharge port is provided at the bottom of the raw material storage tank; The powder absorber is provided with a first air inlet, a first feed inlet and a second discharge inlet, the first feed inlet is selectively connected with the first discharge inlet of the raw material storage tank through a valve, and is selectively connected with the first air inlet and the second discharge inlet, and negative pressure is formed in the powder absorber; the first air inlet is used to introduce a carrier gas into the powder absorber; The heater is provided with a second feed port and a third discharge port, and the second feed port is selectively connected with the second discharge port of the powder absorber; The separator is provided with a guide tube, a first exhaust port and a fourth discharge port, wherein the guide tube is spirally arranged along the inner wall of the separator; the first exhaust port is arranged at the top of the separator to discharge gaseous amine salts; the fourth discharge port is arranged at the bottom of the separator to discharge solid impurities.

46. ​​The apparatus of claim 45, wherein the valve is a rotary feed valve.

47. The device according to claim 45, wherein the heater contains a heating medium, and / or the outer surface of the inner tube of the heater is coated with a heat-conductive metal.

48. The device according to claim 45, wherein the separator is provided with a heating device.

49. The device according to claim 48, wherein the heating device of the separator comprises a heating jacket arranged on the outer wall of the separator and / or a heating cylinder arranged inside the separator.

50. An apparatus for preparing isocyanates, the apparatus being adapted to carry out the method according to any one of claims 39 to 44.

51. A pentamethylenediamine derivative, whose chemical formula is H2N(CH2)5NH2CO2, wherein: The N atom and the C atom are connected by covalent bonds.

52. The pentamethylenediamine derivative according to claim 51, which has an amide ester structure.

53. The pentamethylenediamine derivative according to claim 52, which has the chemical structure shown below:

54. The pentamethylenediamine derivative according to any one of claims 51 to 53, which is present in the form of a mixture.

55. The pentamethylenediamine derivative according to claim 54, comprising the following structure:

56. The pentamethylenediamine derivative according to claim 55, wherein The total molar amount and The molar amounts are essentially the same.

57. The pentamethylenediamine derivative according to any one of claims 51 to 56, which is prepared by the method according to any one of claims 1 to 3.

58. A method for purifying a pentamethylenediamine derivative, wherein the method comprises heating a mixture comprising the pentamethylenediamine derivative according to any one of claims 51 to 56 to a sublimation temperature of the pentamethylenediamine derivative to obtain a gaseous pentamethylenediamine derivative.

59. The method according to claim 58, wherein the sublimation temperature is 70 to 140°C.

60. The method according to claim 58 or 59, wherein the mixture containing pentamethylenediamine derivatives is prepared by the following method: carbon dioxide is introduced into lysine to form lysine carbonate (bicarbonate), and then the lysine carbonate (bicarbonate) is reacted with lysine decarboxylase to generate pentamethylenediamine derivatives.

61. A method for preparing pentamethylene diisocyanate, wherein the method comprises: A phosgenation reaction is carried out under gas phase conditions using the pentamethylenediamine derivative according to any one of claims 51 to 56 as an amine stream and a phosgene stream.

62. The method for preparing pentamethylene diisocyanate according to claim 61, wherein the method comprises the following steps: (a) providing a pentamethylenediamine derivative stream and a phosgene stream and mixing them in a material mixing device; (b) spraying the mixture obtained in step (a) to the diffusion port of the reactor, and resisting the lateral velocity of the material at the discharge end of the material mixing device through a baffle disposed in the reactor near the feed end; (c) The pentamethylenediamine derivative and phosgene in the mixture enter the reaction zone of the reactor and react in the reaction zone to generate pentamethylene diisocyanate.

63. The method according to claim 62, wherein the method further comprises the steps of: (d) collecting pentamethylene diisocyanate prepared in step (c).

64. The method according to claim 61 or 62, wherein the pentamethylenediamine derivative is purified according to the method according to claim 58 or 59.

65. The process according to any one of claims 62 to 63, wherein the pentamethylenediamine derivative in step (a) is in a solid state and the phosgene stream is in a gaseous state.

66. The process of any one of claims 62 to 63, wherein no solvent is used in step (a).

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