Preparation method of vinylene carbonate

Abstract

The invention discloses a preparation method of vinylene carbonate. Specifically, the preparation method provided by the invention comprises the following steps: introducing a material containing chloroethylene carbonate into a reaction bed containing a catalyst, and carrying out a contact reaction to obtain vinylene carbonate, wherein the catalyst is prepared by the following method: molding by using a catalyst raw material, then optionally calcining, and then cooling to obtain catalyst particles. The preparation method disclosed by the invention is low in cost, simple to operate, high in conversion rate, high in yield and beneficial to industrial production.

Description

Technical Field

[0001] The present invention relates to the field of organic synthesis, and particularly to a method for preparing vinylene carbonate. Background Art

[0002] As is well known, vinylene carbonate (VC) can be used in the production of chemicals, pharmaceutical products, and crop protection agents. In particular, it has been widely used in the production of polymers, coatings, and battery electrolytes.

[0003] In the prior art, German Patent DE 1135452 C2 discloses a method for catalyzing the HCl elimination reaction of vinyl chloroformate to produce vinylene carbonate using cadmium chloride supported on an inert carrier as a catalyst.

[0004] Chinese Patent CN 101175742 A discloses a method using zinc chloride supported on an inert carrier as a catalyst and performing the HCl elimination reaction of vinyl chloroformate in a fully mixed and agitated catalytic bed. In this method, a fluidized bed reactor is used for the reaction to ensure sufficient contact between the material and the catalyst. However, the reactor for such a reaction is complex, and the product separation cost and device cost are both relatively high. A fixed bed reactor (also known as a packed bed reactor) has a lower device cost and is therefore more suitable for the industrial production of vinylene carbonate. However, in the prior art, the catalysts used in such reactions are all in powder form. If placed in a fixed bed reaction device for reaction, it is easy to cause problems such as device blockage, affecting the service life of the device. And using a solid phase carrier to support the catalyst is likely to affect the contact between the material and the catalyst, thereby affecting the reaction efficiency.

[0005] Chinese Patent CN108997301 A also discloses a method for preparing vinylene carbonate, which uses triethylamine to react with vinyl chloroformate to remove hydrogen chloride to prepare the target product. However, according to the report of Chinese Patent CN114797957A, such a process will cause the product vinylene carbonate generated in the reaction to mix with triethylamine hydrochloride to form a black viscous substance that is difficult to separate, making the target product vinylene carbonate wrapped by this black viscous substance, which is not conducive to subsequent separation. In addition, it is necessary to consume an equivalent amount of triethylamine, resulting in high production costs. This technical solution can only be applied to batch production and cannot be continuously produced. Moreover, this reaction is a liquid-phase reaction, requiring a large amount of solvent, and a large amount of three wastes will be generated during the production process, which is not environmentally friendly enough.

[0006] In summary, there is an urgent need in the art to develop a method for the industrial production of vinylene carbonate with low cost and high efficiency. Summary of the Invention

[0007] The present invention is made to solve the above problems, and aims to provide a method for efficiently producing vinylene carbonate by a fixed-bed or fluidized-bed process.

[0008] One object of the present invention is to provide a catalyst that does not require a support material and is suitable for the fixed-bed production process of vinylene carbonate.

[0009] Another object of the present invention is to provide a process for preparing vinylene carbonate that can operate stably for a longer period of time without catalyst regeneration.

[0010] In a first aspect of the present invention, there is provided a method for preparing vinylene carbonate, comprising the following steps: introducing a material containing ethylene chlorocarbonate into a reaction bed layer containing a catalyst for contact reaction to obtain vinylene carbonate;

[0011]

[0012] wherein, the catalyst is prepared by the following method: shaping the catalyst raw material, then optionally calcining, and then cooling to obtain catalyst particles; preferably, the reaction temperature is 100 - 400 °C.

[0013] In another preferred embodiment, the contact time is 0.5 - 120 s.

[0014] In another preferred embodiment, the reaction temperature is 300 - 400 °C.

[0015] In another preferred embodiment, the shaping includes: pulverizing the catalyst raw material, fully mixing, and then extruding and shaping.

[0016] In a preferred embodiment, the calcining includes: calcining at 90 - 150 °C for 12 - 48 h, and then calcining at 450 - 550 °C for 5 - 15 h.

[0017] In a preferred embodiment, the reaction is carried out in a reactor filled with a catalyst particle bed layer.

[0018] In a preferred embodiment, the particle size of the catalyst is 1 mm - 5 mm, preferably 2 mm - 4 mm.

[0019] In a preferred embodiment, the inner diameter of the cavity for filling the catalyst particle bed layer in the reactor is 20 mm - 30 mm, and the filling amount of the catalyst is 250 - 350 mL.

[0020] In another preferred embodiment, the specific surface area of the catalyst ≥ 200 m 2 / g, preferably, the specific surface area of the catalyst is 200 m 2 / g - 1000 m 2 / g.

[0021] In a preferred example, the catalyst is prepared by the following method: shaping the catalyst raw materials, then calcining at 100 - 150 °C for 20 - 36 h, calcining at 450 - 550 °C for 8 - 12 h, and then cooling to obtain catalyst particles.

[0022] In a preferred example, the catalyst raw materials include a catalyst selected from Group A; or the catalyst raw materials include a catalyst selected from Group A and a catalyst selected from Group B;

[0023] Group A: oxides of Group IIA, sulfates of Group IIA metals, Group IB metal elements, chlorides of Group IB metals, Group IIB metal oxides, Group IIIA metal chlorides, Group IIIB metal oxides, Group IIIA metal oxides, Group VB metal oxides, Group VIB metal chlorides, Group VIIB metal oxides, Group VIII metal elements, Group VIII oxides, Group VIII metal chlorides, or combinations thereof;

[0024] Group B: oxides of Group IIIA elements, Group IVA elements, Group IVA element oxides, Group IVB metal oxides, Group VIIB metal oxides, or combinations thereof.

[0025] In a preferred example, the catalyst raw materials include a catalyst selected from Group A; or the catalyst raw materials include a catalyst selected from Group A and a catalyst selected from Group B;

[0026] Group A: iron trioxide, magnesium oxide, copper chloride, silver, gallium chloride, gallium oxide, manganese oxide, zinc oxide, indium oxide, cobalt oxide, ferric oxide, ruthenium, cerium dioxide, chromium trichloride, calcium sulfate, palladium oxide, palladium dichloride, nickel oxide, manganese dioxide, vanadium pentoxide, or combinations thereof;

[0027] Group B: titanium dioxide, manganese dioxide, alumina (preferably γ - alumina), silicon dioxide, activated carbon, zirconium oxide, or combinations thereof.

[0028] In a preferred example, the catalyst raw materials include a catalyst selected from Group A; or the catalyst raw materials include a catalyst selected from Group A and a catalyst selected from Group B;

[0029] Group A: iron trioxide, magnesium oxide, copper chloride, silver, gallium chloride, gallium oxide, manganese oxide, zinc oxide, indium oxide, cobalt oxide, ferric oxide, ruthenium, cerium dioxide, or combinations thereof;

[0030] Group B: titanium dioxide, manganese dioxide, alumina (preferably γ - alumina), silicon dioxide, activated carbon, zirconium oxide, or combinations thereof.

[0031] In a preferred embodiment, the gaseous or liquid chloroethylene carbonate is not stirred during the contacting process with the catalyst.

[0032] In a preferred embodiment, the material containing ethylene chlorocarbonate is formed by the following method: a carrier gas preheated to 300°C-450°C and ethylene chlorocarbonate are introduced into a vaporizer preheated to 300°C-450°C, the ethylene chlorocarbonate is vaporized and mixed with the carrier gas, thereby forming a material containing ethylene chlorocarbonate.

[0033] In a preferred embodiment, the carrier gas is selected from the group consisting of argon, helium, neon, nitrogen, carbon monoxide, carbon dioxide, hydrogen chloride gas, water vapor, or a combination thereof.

[0034] In a preferred embodiment, the material containing ethylene chlorocarbonate is formed by the following method: ethylene chlorocarbonate is introduced into a vaporizer having an internal pressure of 100Pa-10000Pa and preheated to 300°C-450°C, so that the ethylene chlorocarbonate is vaporized, thereby forming a material containing ethylene chlorocarbonate.

[0035] In another preferred embodiment, the material containing ethylene chlorocarbonate is formed by the following method: ethylene chlorocarbonate is introduced into a vaporizer having an internal pressure of 700Pa-1000Pa and preheated to 300°C-450°C, so that the ethylene chlorocarbonate is vaporized, thereby forming a material containing ethylene chlorocarbonate.

[0036] In a preferred embodiment, the method further comprises the following steps: passing the product gas stream into a condenser for condensation, thereby obtaining crude vinylene carbonate; preferably, the method further comprises the following steps: distilling the crude vinylene carbonate to obtain vinylene carbonate.

[0037] In another preferred embodiment, the temperature inside the condenser is 50-60°C.

[0038] In another preferred embodiment, the preparation method comprises the following steps:

[0039] S1. Forming a catalyst raw material, then calcining at 90-150 ° C for 12-48h, calcining at 450-550 ° C for 5-15h, and then cooling to obtain catalyst particles; wherein the particle size of the catalyst particles is 1mm-5mm;

[0040] S2. 250-350 mL of catalyst is filled into the reaction bed of the reactor;

[0041] S3. Feed the carrier gas preheated to 300°C - 450°C and ethylene carbonate chloride into the vaporization tank preheated to 300°C - 450°C simultaneously, vaporize the ethylene carbonate chloride and mix it with the carrier gas, thereby forming a material gas stream containing ethylene carbonate chloride;

[0042] S4. Feed the above-mentioned material gas stream containing ethylene carbonate chloride into the reaction bed layer containing the catalyst to make them contact and react to obtain a product gas stream; wherein, the reaction temperature is 300 - 400°C;

[0043] S5. Feed the product gas stream into a condenser for condensation to obtain crude vinylene carbonate;

[0044] S6. Rectify the above-mentioned crude vinylene carbonate to obtain vinylene carbonate.

[0045] In another preferred example, the preparation method includes the following steps:

[0046] S1. Mold the catalyst raw material, then calcine it at 90 - 150°C for 12 - 48 h, calcine it at 450 - 550°C for 5 - 15 h, and then cool it down to obtain catalyst particles; wherein, the particle size of the catalyst particles is 1 mm - 5 mm;

[0047] S2. Fill 250 - 350 mL of the catalyst into the reaction bed layer of the reactor;

[0048] S3. Feed ethylene carbonate chloride into the vaporization tank with an internal pressure of 100 Pa - 10000 Pa and preheated to 300°C - 450°C to vaporize the ethylene carbonate chloride, thereby forming a material gas stream containing ethylene carbonate chloride;

[0049] S4. Feed the above-mentioned material gas stream containing ethylene carbonate chloride into the reaction bed layer containing the catalyst to make them contact and react to obtain a product gas stream; wherein, the reaction temperature is 300 - 400°C;

[0050] S5. Feed the product gas stream into a condenser for condensation to obtain crude vinylene carbonate;

[0051] S6. Rectify the above-mentioned crude vinylene carbonate to obtain vinylene carbonate.

[0052] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as in the examples) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be elaborated one by one here. Description of the Drawings

[0053] Figure 1It is a schematic structural diagram of the continuous flow reaction equipment used in Embodiments 1-2 of the present invention. Detailed implementation manners

[0054] Through long-term and in-depth research, the applicant unexpectedly discovered for the first time that by using the method of calcination after forming, a class of catalysts with long catalyst life and good mechanical strength for producing vinylene carbonate can be prepared. The catalysts can be used in fixed bed or fluidized bed processes for producing vinylene carbonate, with low equipment complexity and low production cost, and are suitable for industrial production. Based on the above discovery, the inventors completed the present invention.

[0055] Terms

[0056] As used herein, the term "Group VIII element" refers to Fe, Co, Ni, ruthenium (Ru), rhodium (Rh), palladium (Pb), osmium (Os), iridium (Ir), platinum (Pt).

[0057] As used herein, the term "Group IB element" refers to Cu, Ag, Au.

[0058] As used herein, the term "Group IIB element" refers to Zn, cadmium (Cd), Hg.

[0059] As used herein, the term "Group IIIB element" refers to scandium (Sc), yttrium (Y), lanthanide elements, actinide elements, where the lanthanide elements include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu).

[0060] As used herein, the term "Group IVB element" refers to titanium (Ti), zirconium (Zr), hafnium (Hf).

[0061] As used herein, the term "Group VB element" refers to vanadium (V), niobium (Nb), tantalum (Ta).

[0062] As used herein, the term "Group VIB element" refers to chromium (Cr), molybdenum (Mo), tungsten (W).

[0063] As used herein, the term "Group VIIB element" refers to manganese (Mn), technetium (Tc), rhenium (Re).

[0064] As used herein, the term "Group IA metal element" refers to lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr).

[0065] As used herein, the term "Group IIA element" refers to beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

[0066] As used herein, the term "Group IIIA element" refers to boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl).

[0067] As used herein, the term "Group IVA element" refers to carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb).

[0068] In this document, when an element has multiple valence states, the corresponding cation can be any valence state. For example, the salts formed by Cu can be copper salts (Cu 2+ ) or cuprous salts (Cu + ).

[0069] As used herein, the terms "phosphate" and "phosphate compound" are used interchangeably and both refer to the salts formed by the combination of the cations of the corresponding elements with phosphate (PO4 3- ).

[0070] As used herein, the terms "sulfate" or "sulfate compound" are used interchangeably and both refer to the salts formed by the combination of the cations of the corresponding elements with sulfate (SO4 2- ).

[0071] The terms "carbonate" or "carbonate compound" are used interchangeably and both refer to the salts formed by the combination of the cations of the corresponding elements with carbonate (CO3 2- ).

[0072] The term "oxide" refers to the complex formed by the corresponding element and oxygen. When the element has multiple stable valence states, the element can be in any valence state.

[0073] The term "fluoride" refers to the complex formed by the corresponding element and fluorine. When the element has multiple stable valence states, the element can be in any valence state.

[0074] The term "chloride" refers to the complex formed by the corresponding element and chlorine. When the element has multiple stable valence states, the element can be in any valence state.

[0075] As used herein, the term "elemental carbon" includes any carbon element, such as activated carbon, graphene, etc.

[0076] Preparation of catalysts applicable to fixed-bed preparation processes

[0077] In the present invention, the preparation of vinylene carbonate is carried out by a fixed-bed process. Since the traditional catalyst for this type of reaction is in powder form and cannot be used in the fixed-bed process, the inventor processed the catalyst in this reaction to form a shaped structure for use in the fixed-bed process.

[0078] In the present invention, an exemplary method for preparing the catalyst is as follows: shaping the catalyst raw materials, then calcining, and then cooling to obtain catalyst particles. Preferably, the calcination includes: calcining at 90 - 130 °C for 12 - 48 h, and then calcining at 450 - 550 °C for 5 - 15 h.

[0079] The catalyst described in the present invention can be a single-component catalyst or a composite catalyst. In a preferred embodiment, the catalyst used in the present invention includes a catalyst selected from Group A (or composed of one or more catalysts selected from Group A); or the catalyst includes a catalyst selected from Group A and a catalyst selected from Group B (or composed of one or more catalysts selected from Group A and one or more catalysts selected from Group B);

[0080] Group A: oxides of Group IIA, sulfates of Group IIA metals, Group IB metals, chlorides of Group IB metals, Group IIB metal oxides, Group IIIA metal chlorides, Group IIIB metal oxides, Group IIIA metal oxides, Group VB metal oxides, Group VIB metal chlorides, Group VIIB metal oxides, Group VIII metals, Group VIII oxides, Group VIII metal chlorides, or combinations thereof;

[0081] Group B: oxides of Group IIIA elements, Group IVA elements, Group IVA element oxides, Group IVB metal oxides, Group VIIB metal oxides, or combinations thereof.

[0082] In another preferred embodiment, the catalyst includes a catalyst selected from Group A; or the catalyst includes a catalyst selected from Group A and Group B;

[0083] Group A: iron tetroxide, magnesium oxide, copper chloride, silver, gallium chloride, gallium oxide, manganese oxide, zinc oxide, indium oxide, cobalt oxide, iron(III) oxide, ruthenium, cerium dioxide, chromium(III) chloride, calcium sulfate, palladium oxide, palladium dichloride, nickel oxide, manganese dioxide, vanadium pentoxide, or combinations thereof;

[0084] Group B: titanium dioxide, manganese dioxide, alumina (preferably γ-alumina), silica, activated carbon, zirconium oxide, or combinations thereof.

[0085] In another preferred embodiment, the catalyst comprises a catalyst selected from Group A; or the catalyst comprises a catalyst selected from Group A and Group B;

[0086] Group A: iron tetroxide, magnesium oxide, copper chloride, silver, gallium chloride, gallium oxide, manganese oxide, zinc oxide, indium oxide, cobalt oxide, ferric oxide, ruthenium, cerium dioxide, or a combination thereof;

[0087] Group B: titanium dioxide, manganese dioxide, alumina (preferably γ-alumina), silica, activated carbon, zirconium oxide, or a combination thereof.

[0088] In a preferred embodiment of the present invention, the catalyst raw materials comprise a catalyst combination selected from the following group: silica, ferric chloride, barium fluoride, titanium dioxide, nickel oxide, manganese dioxide, vanadium pentoxide, nickel oxide, zinc chloride, palladium dichloride / γ-alumina, palladium oxide / silica, calcium sulfate, zinc chloride / silica, chromium trichloride, iron tetroxide, γ-alumina / magnesium oxide, iron tetroxide / silica, copper chloride / activated carbon, silver / silica, magnesium oxide / titanium dioxide / silica, gallium chloride / silica, gallium oxide / magnesium oxide, manganese oxide / zirconium oxide, zinc oxide / silica, indium oxide / γ-alumina, cobalt oxide, ferric oxide / silica, iron tetroxide / silica, silver / silica, iron tetroxide, magnesium oxide / titanium dioxide / silica, ruthenium / activated carbon, manganese dioxide / γ-alumina / cerium dioxide, calcium phosphate, zirconium oxide, or a combination thereof.

[0089] In the present invention, a catalyst suitable for a fixed-bed process is formed by molding and calcining, thereby obtaining a method for efficiently producing vinylene carbonate. In a preferred embodiment, when the catalyst is a single-component catalyst, the following steps are included:

[0090] The raw materials are molded, calcined at 110°C for 24 h, heated to 500°C and calcined for another 10 h, and then cooled naturally to obtain the product. The mechanical strength of the obtained catalyst is greater than 50 N.

[0091] When the catalyst is a multi-component catalyst, the following steps are included:

[0092] The raw materials of each component are mixed evenly, molded, calcined at 110°C for 24 h, heated to 500°C and calcined for another 10 h, and then cooled naturally to obtain the product. The mechanical strength of the obtained catalyst is greater than 50 N.

[0093] In another preferred embodiment, when the catalyst component contains raw materials with a melting point below 500°C (such as ferric chloride, zinc chloride, etc.), after molding, the raw materials are not calcined and are directly used to fill the fixed bed.

[0094] Reactor for preparing vinylene carbonate by continuous flow reaction

[0095] In the following examples, unless otherwise specified, the reaction equipment used is a continuous flow reaction device, and its structural schematic diagram is as shown in Figure 1 shown, specifically including: a vaporization tank, a reactor, a condenser and a receiving tank.

[0096] Among them, the vaporization tank has at least one inlet and one outlet. The inlet is used to simultaneously introduce vinyl chloroformate and a carrier gas. In some embodiments, vinyl chloroformate can be directly introduced without introducing a carrier gas. In this case, the inlet for introducing the carrier gas is closed. The outlet of the vaporization tank is connected to the reactor.

[0097] The reactor has at least one inlet and one outlet. The reactor inlet is connected to the outlet of the vaporization tank, and the outlet of the reactor is connected to the condenser. The reactor also has at least one cavity for accommodating a catalyst. The cavity is cylindrical, with an inner diameter of 26 mm and a height of 300 mm. Specifically, the reactors used in Examples 1-2 are fixed bed reactors, and fluidized bed reactors can also be used in other embodiments. Preferably, there is no stirring device in the reactor.

[0098] In a preferred embodiment, the condenser has at least one inlet and one liquid phase outlet. The inlet of the condenser is connected to the outlet of the reactor, and the liquid phase outlet of the condensate is connected to the receiving tank.

[0099] In a preferred embodiment, the receiving tank has at least one inlet and one outlet. The inlet of the receiving tank is connected to the outlet of the condenser, and the outlet of the receiving tank is used to discharge the collected product.

[0100] In a preferred embodiment, both the vaporization tank and the reactor have heating and temperature control functions.

[0101] In a preferred embodiment, the condenser also has a gas phase outlet, and the gas phase outlet is used to discharge uncondensed components (mainly HCl). In another preferred embodiment, after the uncondensed components are discharged from the gas phase outlet, they are introduced into water for further absorption.

[0102] Advantages of the present invention

[0103] (1) The preparation method of vinylene carbonate of the present invention adopts a fixed bed process, and there is no need to additionally agitate the catalyst during the reaction, so the cost of the production device is greatly reduced, the production process is simplified, and even during long-term operation, the catalyst will not be pulverized.

[0104] (2) The present invention provides a catalyst suitable for a fixed bed. During the preparation of the catalyst, the catalyst is first formed and then calcined. The obtained catalyst has high mechanical strength and will not pulverize during the reaction. The single life of the catalyst can reach up to more than 100 hours, and the cumulative life after activation can reach more than 1000 hours.

[0105] (3) The prior art suggests the use of a variety of different metal elements or complexes as catalysts. However, the inventors have found that when a fixed bed process is used and a shaped catalyst is used, the use of an oxide-containing catalyst can achieve a yield far superior to that of other catalyst types.

[0106] (4) A new composite catalyst was used to reduce the side reaction of deep cracking while maintaining a conversion rate of more than 98%, thereby increasing the product yield to a maximum of 84%, which is better than the existing technology.

[0107] In order to make the technical means, creative features, purpose and effect of the present invention easy to understand, the present invention is described in detail below in conjunction with Examples and accompanying drawings. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are weight percentages and parts by weight, and each raw material is a commercially available product.

[0108] General Methods: Preparation of Catalysts

[0109] In various embodiments of the present invention, when the catalyst is a single-component catalyst, the catalyst is prepared by the following steps:

[0110] i. Molding the raw materials: Powder and mix the raw materials thoroughly, extrude with a single screw, and cut into spheres;

[0111] ii. Calcination: calcined at 110 ° C for 24 h, then heated to 500 ° C and continued calcined for 10 h;

[0112] iii. Let it cool down naturally.

[0113] When the catalyst is a multi-component catalyst, the catalyst is prepared by the following steps:

[0114] I. Mix all the raw materials evenly and shape them: grind the raw materials into powder and mix them thoroughly, extrude them into balls with a single screw, and cut them into spheres;

[0115] II. Calcination: Calcination at 110 ° C for 24 h, then heating to 500 ° C and continuing calcination for 10 h;

[0116] III. Let the temperature drop naturally.

[0117] Performance test of the catalyst

[0118] The mechanical strength of the catalyst was detected according to GB 3635-1983, and the test results showed that the mechanical strength of the obtained catalyst was greater than 50 N.

[0119] In addition, the BET test method was used for testing, and the specific surface area of each catalyst prepared by the present invention was measured to be greater than 200 m 2 / g.

[0120] Example 1 Preparation of vinylene carbonate

[0121] This example provides a method for preparing vinylene carbonate, and the reaction steps are as follows:

[0122] The pressure in the vaporization tank was controlled between 800 Pa and 900 Pa, and the internal atmosphere was heated to 300 °C. Vinyl chloroformate was introduced into the vaporization tank at a feeding rate of 25 mL / min. The vinyl chloroformate entering the vaporization tank was quickly vaporized, and the vaporized vinyl chloroformate was introduced into the reactor at a rate of 25 mL / min. The inside of the reactor had been preheated to 360 °C, and the reactor was filled with 300 mL of iron oxide catalyst with an average particle size of 3 mm. Under the action of the catalyst, vinyl chloroformate underwent a cracking reaction to form vinylene carbonate, and the average residence time of the material in the reactor was 1 s. The product gas stream exited the reactor and entered the condenser, where the product was condensed to 50 °C, the product was liquefied into a liquid, and the liquefied product was introduced into the receiving tank for collection to obtain the crude product.

[0123] When the reaction proceeded to 48 h, a sample was taken from the outlet of the condenser and subjected to GC detection. The GC spectrum is shown in the following table. When the reaction proceeded to 48 h, the reaction conversion rate was still as high as 99.2%, and the content of the target product vinylene carbonate in the sample was 91.2%:

[0124] <Peak table>

[0125] FID1

[0126]

[0127] The crude product generated during the 48 h reaction was collected and subjected to rectification purification, and finally vinylene carbonate with a purity of 99.5% was obtained at a yield of 76%.

[0128] Example 2 Preparation of vinylene carbonate

[0129] This example provides a method for preparing vinylene carbonate, and the reaction steps are as follows:

[0130] The nitrogen used as the carrier gas is heated to 300 °C and then introduced into the vaporization tank preheated to 300 °C at a rate of 8 L / min. At the same time, liquid vinyl chloroformate is introduced into the vaporization tank at a rate of 25 mL / min. The vinyl chloroformate vaporizes rapidly, and the vaporized vinyl chloroformate enters the reactor along with the carrier gas. The inside of the reactor has been preheated to 360 °C, and the reactor is filled with 300 mL of iron oxide with an average particle size of 3 mm. Under the action of the catalyst, vinyl chloroformate undergoes a cracking reaction to generate vinylene carbonate, and the average residence time of the material in the reactor is 1.5 s. The product gas stream exits the reactor and enters the condenser, where the product is condensed to 50 °C, the product liquefies into a liquid, and the liquefied product is introduced into the receiving tank for collection to obtain the crude product.

[0131] When the reaction proceeds to the 48th hour, a sample is taken from the outlet of the condenser and subjected to GC detection. The GC detection results are shown in the following table. When the reaction proceeds to the 48th hour, the reaction conversion rate is still as high as 99.2%, and the content of the target product vinylene carbonate in the sample is 85.1%:

[0132] <Peak table

[0133] FID1

[0134]

[0135] The crude product generated during the 48-hour reaction is collected and subjected to rectification purification, and finally vinylene carbonate with a purity of 99.5% is obtained at a yield of 69%.

[0136] Example 3 Catalyst Screening

[0137] In this example, based on Examples 1-2, the catalyst was screened. The screening methods include the following two:

[0138] Method A:

[0139] Control the pressure in the vaporization tank between 800 Pa and 900 Pa, heat the internal atmosphere to 300 °C, and introduce vinyl chloroformate into the vaporization tank at a feeding rate of 25 mL / min. The vinyl chloroformate entering the vaporization tank vaporizes rapidly and is introduced into the reactor at a rate of 25 mL / min. The inside of the reactor has been preheated to 360 °C, and the reactor is filled with 300 mL of catalyst with an average particle size of 3 mm. Under the action of the catalyst, vinyl chloroformate undergoes a cracking reaction to form vinylene carbonate, and the average residence time of the material in the reactor is 1.5 s. The product gas stream exits the reactor and enters the condenser, where the product is condensed to 50 °C, the product liquefies into a liquid, and samples are taken from the condenser outlet every 30 min as samples to detect the reaction conversion rate and the content of vinylene carbonate in the samples. The liquefied product is introduced into a receiving tank for collection to obtain a crude product. The crude product collected within 48 h of the reaction is collected and purified by distillation to obtain vinylene carbonate.

[0140] Method B:

[0141] Heat nitrogen as the carrier gas to 300 °C and introduce it into the vaporization tank preheated to 300 °C at a rate of 8 L / min. At the same time, introduce liquid vinyl chloroformate into the vaporization tank at a rate of 25 mL / min. The vinyl chloroformate vaporizes rapidly, and the vaporized vinyl chloroformate enters the reactor along with the carrier gas. The inside of the reactor has been preheated to 360 °C, and the reactor is filled with 300 mL of catalyst with an average particle size of 3 mm. Under the action of the catalyst, vinyl chloroformate undergoes a cracking reaction to form vinylene carbonate, and the average residence time of the material in the reactor is 1.5 s. The product gas stream exits the reactor and enters the condenser, where the product is condensed to 50 °C, the product liquefies into a liquid, and samples are taken from the condenser outlet every 30 min as samples to detect the reaction conversion rate and the content of vinylene carbonate in the samples. The liquefied product is introduced into a receiving tank for collection to obtain a crude product. The crude product collected within 48 h of the reaction is collected and purified by distillation to obtain vinylene carbonate.

[0142] The screening results are shown in Table 1.

[0143] Table 1 Screening of Catalysts

[0144]

[0145]

[0146] a. In the multi-component catalyst, each percentage is a mass percentage;

[0147] b. Conversion rate = (1 - content of vinyl chloroformate) × 100%, and the content of vinyl chloroformate = the content of vinyl chloroformate determined by GC detection in the sample taken from the condenser outlet when the reaction proceeds to 48 h;

[0148] c. VC content = the content of vinylene carbonate determined by GC detection in the sample taken from the condenser outlet when the reaction proceeds to 48 h;

[0149] d. VC yield = the molar amount of vinylene carbonate obtained after rectification of the crude product collected from the reaction from 0 - 48 h / the molar amount of vinyl chloroformate consumed in the reaction from 0 - 48 h, and the purity of the vinylene carbonate obtained after rectification is ≥ 99.5%;

[0150] e. Catalyst life = the time from the start of the reaction to when the conversion rate is lower than 50% for the first time;

[0151] f. Reactor temperature: 300 °C;

[0152] g. Prepared with reference to Example 1 of CN200680016151.X;

[0153] h. The preparation method is to mix the raw materials and then form them to obtain the product. The forming method is the same as that of other catalysts, but does not include the calcination step.

[0154] As can be seen from the above table, the catalyst provided by this application has significantly better effects than some catalysts reported in the existing literature. Since the catalyst provided by this application has gone through steps such as forming and calcination, the overall mechanical strength is much greater than that of traditional catalysts using carriers. Therefore, no pulverization phenomenon will occur during the reaction, and the catalyst life can reach up to more than 100 h. It can be seen from entry 25 and 36 in Table 1 that when other conditions are the same and only the catalyst is calcined, the catalyst life, product conversion rate, etc. are all significantly improved. This result shows that calcining the catalyst can effectively improve the catalyst life, product conversion rate, and the content of VC in the product in the process of this invention.

[0155] In terms of the selection of catalyst types, the applicant found that the effects of chlorides are generally poor. This is because chloride transition metal chloride catalysts represented by zinc chloride will cause an increase in side reactions of deep cracking and serious carbon deposition on the catalyst, resulting in the inability of the catalytic reaction to proceed smoothly. However, using oxides as catalysts can achieve a much better yield than when using other catalyst types.

[0156] The above embodiments are preferred cases of the present invention and are not used to limit the protection scope of the present invention.

[0157] All documents mentioned in this invention are cited in this application by reference as if each individual document was cited by reference. In addition, it should be understood that after reading the above teachings of this invention, those skilled in the art can make various changes or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

Claims

1. A method for preparing vinylene carbonate, characterized in that, It includes the following steps: feeding a material containing vinyl chloroformate into a reaction bed containing a catalyst to make them contact and react, thereby obtaining vinylene carbonate; Among them, the catalyst is prepared by the following method: shaping the catalyst raw material, then optionally calcining, and then cooling to obtain catalyst particles; preferably, the reaction temperature is 100 - 400 °C.

2. The preparation method according to claim 1, characterized in that, The calcination includes: calcining at 90 - 150 °C for 12 - 48 h, and then calcining at 450 - 550 °C for 5 - 15 h.

3. The preparation method according to claim 1, characterized in that, The reaction is carried out in a reactor filled with a catalyst particle bed.

4. The preparation method according to claim 1, characterized in that, The particle size of the catalyst is 1 mm - 5 mm, preferably 2 mm - 4 mm.

5. The preparation method according to claim 3, wherein, The inner diameter of the cavity for filling the catalyst particle bed in the reactor is 20 mm - 30 mm, and the filling amount of the catalyst is 250 - 350 mL.

6. The preparation method according to claim 1, characterized in that, The catalyst is prepared by the following method: shaping the catalyst raw material, then calcining at 100 - 150 °C for 20 - 36 h, calcining at 450 - 550 °C for 8 - 12 h, and then cooling to obtain catalyst particles.

7. The preparation method according to claim 1, characterized in that, The catalyst raw material includes a catalyst selected from Group A; or the catalyst raw material includes a catalyst selected from Group A and a catalyst selected from Group B; Group A: oxides of Group IIA, sulfates of Group IIA metals, Group IB metal elements, chlorides of Group IB metals, Group IIB metal oxides, Group IIIA metal chlorides, Group IIIB metal oxides, Group IIIA metal oxides, Group VB metal oxides, Group VIB metal chlorides, Group VIIB metal oxides, Group VIII metal elements, Group VIII oxides, Group VIII metal chlorides, or combinations thereof; Group B: oxides of Group IIIA elements, Group IVA element elements, Group IVA element oxides, Group IVB metal oxides, Group VIIB metal oxides, or combinations thereof.

8. The preparation method according to claim 7, wherein The catalyst raw material includes a catalyst selected from Group A; or the catalyst raw material includes a catalyst selected from Group A and a catalyst selected from Group B; Group A: iron trioxide, magnesium oxide, copper chloride, silver, gallium chloride, gallium oxide, manganese oxide, zinc oxide, indium oxide, cobalt oxide, iron(III) oxide, ruthenium, cerium dioxide, chromium(III) chloride, calcium sulfate, palladium oxide, palladium dichloride, nickel oxide, manganese dioxide, vanadium pentoxide, or combinations thereof; Group B: titanium dioxide, manganese dioxide, alumina (preferably γ - alumina), silicon dioxide, activated carbon, zirconium oxide, or combinations thereof.

9. The preparation method according to claim 7, wherein The catalyst raw material includes a catalyst selected from Group A; or the catalyst raw material includes a catalyst selected from Group A and a catalyst selected from Group B; Group A: iron trioxide, magnesium oxide, copper chloride, silver, gallium chloride, gallium oxide, manganese oxide, zinc oxide, indium oxide, cobalt oxide, iron(III) oxide, ruthenium, cerium dioxide, or combinations thereof; Group B: titanium dioxide, manganese dioxide, alumina (preferably γ - alumina), silicon dioxide, activated carbon, zirconium oxide, or combinations thereof.

10. The preparation method according to claim 1, wherein, During the process of the gaseous or liquid vinyl chloroformate contacting the catalyst, stirring is not carried out.

11. The preparation method according to claim 1, characterized in that, The material containing vinyl chloroformate is formed by the following method: A carrier gas preheated to 300°C - 450°C and vinyl chloroformate are introduced into a vaporization tank preheated to 300°C - 450°C, so that the vinyl chloroformate is vaporized and mixed with the carrier gas, thereby forming a material containing vinyl chloroformate.

12. The preparation method according to claim 11, wherein, The carrier gas is selected from the group consisting of: argon, helium, neon, nitrogen, carbon monoxide, carbon dioxide, hydrogen chloride gas, water vapor, or a combination thereof.

13. The preparation method according to claim 1, wherein, The material containing vinyl chloroformate is formed by the following method: Vinyl chloroformate is introduced into a vaporization tank with an internal pressure of 100 Pa - 10,000 Pa and preheated to 300°C - 450°C, so that the vinyl chloroformate is vaporized, thereby forming a material containing vinyl chloroformate.

14. The preparation method according to claim 1, characterized in that, The method further comprises the following steps: passing the product gas stream into a condenser for condensation to obtain a crude product of vinylene carbonate; preferably, the method further comprises the following steps: rectifying the crude product of vinylene carbonate to obtain vinylene carbonate.

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