Continuous synthesis system for preparing amine compound by using carboxylic acid or carboxylic ester as raw material

Abstract

The utility model discloses a continuous synthesis system for preparing amine compounds by using carboxylic acid or carboxylic ester as a raw material, in the system, carboxylic acid or carboxylic ester and ammonia gas are subjected to continuous catalytic ammoniation dehydration reaction in a solvent-free state to generate nitrile compounds, nitrile-containing high-temperature mixed gas generated by an ammoniation dehydration device directly enters an injection unit without being subjected to cooling separation, and the nitrile-containing high-temperature mixed gas is injected into the injection unit. The raw materials are sequentially pressurized and cooled by a solvent jet device and a high-pressure hydrogen injection device, meanwhile, highly dispersed gas-liquid mixed raw materials are formed, and then the gas-liquid mixed raw materials enter a catalytic hydrogenation reaction device to be continuously synthesized into organic amine. According to the system, effective connection of a high-temperature low-pressure nitrile synthesis process and a low-temperature high-pressure amine synthesis process is realized by utilizing the injection unit, multi-step treatment processes such as repeated heating and cooling, separation and purification and the like in a traditional process are avoided, the process flow is shortened, and the whole process system is continuous, efficient, safe and environment-friendly.

Description

Technical Field

[0001] The utility model relates to the field of preparing organic amines by catalytic hydrogenation of nitrile compounds, and more specifically to a continuous synthesis system for preparing organic amines by catalytic hydrogenation of nitrile compounds using carboxylic acid or carboxylic acid ester as raw materials through ammoniation and dehydration. Background Art

[0002] Amine is a very important organic compound and an important intermediate in the preparation of natural products and drug molecules. It has a wide range of applications in dyes, medicines, pesticides, surfactants and materials science. For example, hexamethylenediamine can be used to produce nylon 66, and meta-phenylenediamine can be used to produce epoxy resin curing agents and nylon products. Amines can also undergo diazotization reactions to generate diazonium salts or prepare azo dyes. They have a wide range of uses and a broad market.

[0003] There are many processes for producing amines. The hydrogenation of nitriles to produce amines is an industrial synthetic route with high atom economy and environmental friendliness for producing amine compounds. This catalytic hydrogenation route has high production efficiency, cheap reaction raw materials, less waste generated during the reaction, and low energy consumption.

[0004] The domestically operated processes for producing hexamethylenediamine by catalytic hydrogenation of adiponitrile mainly include high-pressure process and low-pressure process. Usually, the high-pressure adiponitrile hydrogenation process uses a three-phase fluidized bed as its reactor type, and uses liquid ammonia, aromatic hydrocarbons, etc. as reaction solvents. The low-pressure reactor is mostly a liquid phase fluidized bed or a fixed bed. In addition, Chinese patent CN1251087A discloses a method for continuous hydrogenation of adiponitrile, which uses a kettle reactor and uses a sponge cobalt catalyst in a reaction medium that is basically free of alkali to catalyze the hydrogenation of adiponitrile at relatively low temperature and low pressure.

[0005] Domestic industrial production of m-xylenediamine generally adopts the catalytic hydrogenation process of isophthalonitrile, mainly using intermittent kettle reaction. Major international manufacturers, such as Japan's Mitsubishi Gas, use a trickle bed continuous production process, and Germany's BASF uses a fixed bed continuous catalytic process. Intermittent kettle reactions generally use magnetic or mechanical stirring, and it is difficult to ensure sufficient hydrogen supply on the catalyst surface, resulting in too many imine intermediates in the reaction liquid and too many by-products. In addition, the production scale is small, the catalyst is easy to pulverize, the separation effect is poor, and there are problems such as high production cost, poor safety, and low degree of automation.

[0006] In summary, the catalytic hydrogenation of nitriles to produce amines, especially aliphatic primary amines, usually requires an alkaline environment under high pressure and high hydrogen-nitrile ratio conditions to inhibit the formation of by-products such as secondary amines and tertiary amines. However, the raw material nitrile compounds required for amine production are generally synthesized under high temperature, normal pressure or low pressure conditions. For example, m-xylene is subjected to ammoxidation reaction to prepare isophthalonitrile at normal pressure, using a vanadium catalyst and a reaction temperature of 400-425°C. Salicylamide uses a solid acid catalyst and catalytic dehydration at 300-350°C to produce salicylonitrile, etc. The nitrile compounds produced cannot directly enter the downstream high-pressure reactor for catalytic hydrogenation to produce amines. They must first be cooled, separated and purified, and then pumped into a continuous catalytic hydrogenation system through liquefaction, or an intermittent kettle catalytic hydrogenation process is used to feed in batches. The process is complicated and the operation is cumbersome.

[0007] Therefore, the development of a new and efficient integrated continuous production system for nitrile amines is of great significance to the industrial production of bulk organic amine intermediates. Utility Model Content

[0008] In view of the problems existing in the above-mentioned prior art, the purpose of the utility model is to provide a continuous synthesis system for preparing amine compounds using carboxylic acid or carboxylic acid ester as raw material, in which carboxylic acid or carboxylic acid ester and ammonia are continuously catalyzed by ammoniation and dehydration reaction in a solvent-free state to generate nitrile compounds, and the high-temperature mixed gas containing nitrile produced by the ammoniation and dehydration device is directly fed into an ejector unit without cooling and separation, and is pressurized and cooled by a solvent jet device and a high-pressure hydrogen ejector device in turn, and a highly dispersed gas-liquid mixed raw material is formed at the same time, and then enters a catalytic hydrogenation reaction device to continue synthesizing organic amines. The system utilizes an ejector unit to realize the effective connection between the high-temperature and low-pressure nitrile synthesis process and the low-temperature and high-pressure amine synthesis process, avoiding the multi-step treatment process of repeated heating and cooling, separation and purification in the traditional process, shortening the process flow, and making the entire process system continuous, efficient, safe and environmentally friendly.

[0009] The technical solution of the utility model is as follows:

[0010] A continuous synthesis system for preparing amine compounds using carboxylic acid or carboxylic acid ester as raw materials mainly comprises: a nitrile synthesis unit, an ejection unit, an amine synthesis unit, a separation unit, and a circulation unit;

[0011] The nitrile synthesis unit mainly comprises a preheating device and a continuous ammoniation and dehydration reaction device connected in sequence, wherein the preheating device is used to preheat the raw material carboxylic acid or carboxylate and the raw material gas ammonia respectively, and the continuous ammoniation and dehydration reaction device is located downstream of the nitrile synthesis unit and connected by a pipeline, receives the reaction materials from the preheating device and mainly comprises an ammoniation and dehydration reactor, and the preheated carboxylic acid or carboxylate and ammonia react catalytically in the ammoniation and dehydration reactor to synthesize nitrile compounds, and the product is a high-temperature mixed gas composed of the generated gas-phase nitrile compounds and unreacted ammonia and water vapor;

[0012] The ejector unit is located downstream of the continuous ammoniation and dehydration reaction device and connected via a pipeline, and mainly comprises a solvent ejector and a hydrogen ejector, and is used to receive the high-temperature mixed gas containing nitrile produced by the nitrile synthesis unit, wherein the solvent ejector ejects a solvent to the high-temperature mixed gas containing nitrile, and the hydrogen ejector is located downstream of the solvent ejector, and is used to eject high-pressure hydrogen to the high-temperature mixed gas containing nitrile to form a high-pressure and low-temperature catalytic hydrogenation reaction raw material mixture;

[0013] The amine synthesis unit is located downstream of the ejector unit and connected by a pipeline, and includes a catalytic hydrogenation reaction device and a cooling device. The catalytic hydrogenation reaction device mainly includes a hydrogenation reactor, and the mixed reaction materials transported from the ejector unit and fresh hydrogen are subjected to catalytic hydrogenation reaction in the hydrogenation reactor to synthesize organic amine compounds; the cooling device is located downstream of the catalytic hydrogenation reaction device and is used to cool the mixed materials after the catalytic hydrogenation reaction;

[0014] The separation unit is located downstream of the amine synthesis unit and connected via a pipeline, and includes a gas-liquid two-phase separation device, which receives the cooled mixed material from the amine synthesis unit and obtains a liquid crude amine solution after two-phase separation;

[0015] The circulation unit is connected to the preheating device, the hydrogen ejector device and the gas-liquid separation device through a pipeline, and mainly includes a membrane separation device, a hydrogen booster device and an ammonia pressure reducing device, and is used to receive the mixed gas from the separation unit, separate and adjust the pressure of the mixed gas, and recycle the hydrogen and ammonia respectively, wherein the membrane separation device is mainly used to separate the hydrogen from the ammonia in the mixed gas;

[0016] The hydrogen booster device is used to receive the hydrogen from the membrane separation device and circulate it back to the hydrogen ejector device after boosting the hydrogen;

[0017] The ammonia pressure reducing device is used to receive ammonia from the gas membrane separation device and reduce the pressure to circulate back to the nitrile synthesis unit, and then continue to be used for synthesizing nitrile compounds after being mixed with fresh ammonia.

[0018] Preferably, the preheating device is a heat exchanger group, and the connection form can be parallel, series, or a combination of series and parallel. The specific equipment form includes but is not limited to a shell and tube heat exchanger, an electric heating heat exchanger, a heating furnace, etc.

[0019] Preferably, the ammoniation and dehydration reactor in the continuous ammoniation and dehydration reaction device can be a fixed bed reactor or a fluidized bed reactor. When a fluidized bed reactor is used, the raw material can be directly fed without preheating when it is solid or liquid.

[0020] Preferably, the solvent injection device can adopt a jet pump; the hydrogen injection device can adopt a Laval tube or a Venturi structure, and the hydrogen injection device can be a single-stage injection or a multi-stage injection, and the number of stages is preferably one to three.

[0021] Preferably, the hydrogenation reactor in the catalytic hydrogenation reaction device includes but is not limited to a fixed bed reactor, a trickle bed reactor and a tubular reactor; preferably, when the catalytic hydrogenation reaction is a gas-solid phase reaction, a preheater can be added before the reactor to completely gasify the mixed raw material before introducing it into the reactor.

[0022] Preferably, the membrane separation device may be an industrial hydrogen membrane separation device.

[0023] Preferably, the hydrogen boosting device includes but is not limited to a hydrogen compressor.

[0024] Preferably, the ammonia pressure reducing device mainly includes adsorption, drying equipment and pressure reducing equipment, and the pressure reducing equipment includes but is not limited to a pressure reducing valve, a throttling orifice plate, an expander, etc.

[0025] Beneficial Effects

[0026] The utility model provides a green process for the continuous synthesis of nitrile compounds by solvent-free continuous gas-phase catalytic synthesis of carboxylic acid or carboxylic acid ester and ammonia, and provides an efficient integrated continuous synthesis system for nitrile-amine. Nitriles generated under low pressure or normal pressure do not need to be separated by cooling, and directly enter the downstream catalytic hydrogenation reaction device through a hydrogen ejector to prepare organic amines. The downstream amine synthesis of this process makes full use of the excess ammonia during the upstream nitrile synthesis to suppress the generation of secondary amines and tertiary amines as by-products, and separates ammonia and hydrogen by membrane separation, so that ammonia and hydrogen can be recycled, realizing a double-circulation nitrile-amine continuous synthesis integrated process system in which ammonia is circulated in the nitrile synthesis unit and the amine synthesis unit, and hydrogen is circulated in the amine synthesis unit. The system has a compact structure and reasonable matching of logistics and energy flows, and is an energy-saving, environmentally friendly, economical and efficient green process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the drawings that are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar parts. The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the specification and claims, are used to illustrate the embodiments of the utility model. When appropriate, the same reference numerals are used in all drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present device or method.

[0028] Figure 1The present invention is a schematic structural diagram of preparing an amine compound using a carboxylic acid or a carboxylic acid ester as a raw material according to one embodiment of the present invention.

[0029] Reference numerals:

[0030] 1-nitrile synthesis unit: 11-continuous amination and dehydration reaction device, 12-preheating device;

[0031] 2-injection unit: 21-solvent injection device, 22-hydrogen injection device;

[0032] 3-amine synthesis unit: 31-catalytic hydrogenation reaction device, 32-cooling device;

[0033] 4-Separation unit: 41-Gas-liquid separation device,

[0034] 5-Circulation unit: 51-Membrane separation device, 52-Hydrogen boosting device, 53-Ammonia pressure reducing device. DETAILED DESCRIPTION

[0035] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but are not intended to limit the present invention.

[0036] It should be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the following description should not be considered as limiting, but merely as an example of an embodiment. Other modifications within the scope and spirit of the present disclosure will occur to those skilled in the art.

[0037] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the general description of the present disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.

[0038] These and other characteristics of the invention will become apparent from the following description of a preferred form of embodiment given as a non-limiting example, with reference to the accompanying drawings.

[0039] It should also be understood that although the present invention has been described with reference to some specific examples, those skilled in the art will be able to realize many other equivalent forms of the present invention that have the features described in the claims and are therefore within the scope of protection defined thereby.

[0040] The above and other aspects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0041] Specific embodiments of the present disclosure are described hereinafter with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to avoid obscuring the present disclosure with unnecessary or redundant details. Therefore, the specific structural and functional details disclosed herein are not intended to be limiting, but merely serve as a basis and representative basis for the claims to teach those skilled in the art to use the present disclosure in a variety of ways with substantially any suitable detailed structure.

[0042] This specification may use the phrases "in one embodiment," "in another embodiment," "in a further embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present disclosure.

[0043] The following is combined with Figure 1 To further describe the utility model in detail.

[0044] According to one embodiment of the utility model, a synthesis process system for preparing amine compounds from carboxylic acids or carboxylic acid esters is provided, which comprises five units in sequence: a nitrile synthesis unit 1, a hydrogen injection unit 2, an amine synthesis unit 3, a separation unit 4, and a circulation unit 5.

[0045] The nitrile synthesis unit 1 mainly comprises a preheating device 12 and a continuous amination and dehydration reaction device 11 which are connected in sequence.

[0046] The preheating device 12 is used to preheat the raw carboxylic acid or carboxylic acid ester and the raw gas ammonia respectively, and the raw gas ammonia includes fresh ammonia and recycled ammonia.

[0047] The continuous amination and dehydration reaction device 11 is located downstream of the nitrile synthesis unit 1 and connected by a pipeline, receives the reaction materials from the preheating device and mainly includes an amination and dehydration reactor and its auxiliary equipment. The amination and dehydration reactor is pre-installed with an amination and dehydration catalyst. The continuous amination and dehydration reaction device 11 is used to receive the reaction materials from the preheating device 12. The preheated carboxylic acid or carboxylic acid ester and ammonia are catalytically reacted in the amination and dehydration reaction device 11 to synthesize nitrile compounds. The generated nitrile compounds are high-temperature mixed gases composed of gas phase and unreacted ammonia, water vapor, etc., and are finally discharged from the outlet of the amination and dehydration reaction device 11.

[0048] The ejector unit 2 is located downstream of the continuous ammoniation dehydration reaction device 11 and connected by a pipeline. It mainly includes a solvent ejector device 21 and a hydrogen ejector device 22, which is used to receive the high-temperature mixed gas containing nitrile produced by the nitrile synthesis unit 1. The solvent ejector device 21 ejects solvent to the high-temperature mixed gas containing nitrile. The high-temperature mixed gas containing nitrile is first subjected to the entrainment and shearing action of the high-speed solvent jet in the solvent ejector device 21. Nitrile compounds and part of ammonia are dissolved in the solvent, and the insoluble gas is highly dispersed in the solution. The heat of the high-temperature mixed gas is also utilized during the mixing process to form a gas-liquid mixture with a suitable temperature. The hydrogen ejector device 22 is located downstream of the solvent ejector device 21, and the gas-liquid mixture then enters the hydrogen ejector device 22. The high-pressure hydrogen returned by the circulation unit 5 ejects the gas-liquid mixture, so that the gas-liquid mixture is strongly mixed with the high-pressure hydrogen, and finally forms a high-pressure and low-temperature catalytic hydrogenation reaction raw material mixture.

[0049] The amine synthesis unit 3 , which is located downstream of the ejector unit 2 and connected via a pipeline, includes a catalytic hydrogenation reaction device 31 and a cooling device 32 .

[0050] The catalytic hydrogenation reaction device 31 mainly includes a hydrogenation reactor and its ancillary equipment. The hydrogenation reactor is pre-installed with a hydrogenation catalyst. The catalytic hydrogenation reaction device 31 is used to receive the mixed reaction materials and fresh hydrogen delivered from the ejector unit 2. Then, the nitrile compounds undergo catalytic hydrogenation reaction in the catalytic hydrogenation reaction device 31 to synthesize organic amine compounds.

[0051] The cooling device 32 is located downstream of the catalytic hydrogenation reaction device 31 and is used to cool the materials after the hydrogenation reaction, usually to below the boiling point of the product, so as to facilitate gas-liquid separation of unreacted hydrogen and ammonia and the product.

[0052] The separation unit 4 is located downstream of the amine synthesis unit 3 and connected via a pipeline, and includes a gas-liquid two-phase separation device 41, which receives the cooled mixed material from the amine synthesis unit 3, and obtains a liquid phase crude amine solution after two-phase separation, and the gas phase mainly contains unreacted hydrogen, ammonia and other small amounts of gas phase products.

[0053] The circulation unit 5 is connected to the preheating device 12, the hydrogen ejection device 22 and the gas-liquid separation device 41 through a pipeline, and mainly includes a membrane separation device 51, a hydrogen boosting device 52 and an ammonia pressure reducing device 53, which are used to receive the mixed gas from the separation unit 4 and realize the separation, pressure regulation and circulation return of the mixed gas.

[0054] The membrane separation device 51 is mainly used to separate hydrogen and ammonia in the mixed gas.

[0055] The hydrogen boosting device 52 is used to receive the hydrogen from the membrane separation device 51 and circulate the hydrogen back to the hydrogen ejecting device 22 after boosting the hydrogen.

[0056] The ammonia pressure reducing device 53 is used to receive the ammonia from the membrane separation device 51 and circulate it back to the nitrile synthesis unit 1 under reduced pressure, and then continue to be used for synthesizing nitrile compounds after being mixed with fresh ammonia.

[0057] Preferably, the preheating device 12 is a heat exchanger group, and the connection form can be parallel, series, or a combination of series and parallel. The specific equipment form includes but is not limited to a shell and tube heat exchanger, an electric heating heat exchanger, a heating furnace, etc.

[0058] Preferably, the reactor in the continuous ammoniation and dehydration reaction device 11 can be a fixed bed reactor or a fluidized bed reactor. When a fluidized bed reactor is used, the raw material can be directly fed without preheating when it is solid or liquid.

[0059] Preferably, the solvent injection device 21 can adopt a jet pump and its auxiliary equipment; the hydrogen injection device 22 can adopt a Lava tube or a Venturi structure, and the hydrogen injection device 22 can be a single-stage injection or a multi-stage injection, and the number of stages is preferably one to three.

[0060] Preferably, the reactor in the catalytic hydrogenation reaction device 31 may include but is not limited to a fixed bed reactor, a trickle bed reactor and a tubular reactor; wherein the catalytic hydrogenation reaction may be a gas-liquid-solid reaction or a gas-solid reaction. When the catalytic hydrogenation reaction is a gas-solid phase reaction, a preheater may be added before the reactor to completely gasify the mixed raw material before introducing it into the reactor.

[0061] Preferably, the catalytic hydrogenation reaction unit 31 can increase the feed of alkaline solution, or the catalyst used contains a solid alkaline component to inhibit the generation of secondary amine and tertiary amine by-products.

[0062] Preferably, the membrane separation device 51 may be an industrial hydrogen membrane separation device.

[0063] Preferably, the hydrogen boosting device 52 includes but is not limited to a hydrogen compressor.

[0064] Preferably, the ammonia pressure reducing device 53 mainly includes adsorption, drying equipment and pressure reducing equipment, and the pressure reducing equipment includes but is not limited to a pressure reducing valve, a throttling orifice plate, an expander, etc.

[0065] The continuous amination and dehydration reaction device 11, the catalytic hydrogenation reaction device 31 and the solvent injection device 22 also include conventional auxiliary equipment.

[0066] Preferably, the carboxylic acid raw material is selected from phthalic acid, terephthalic acid, glutaric acid, adipic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, isophthalic acid, methacrylic acid, n-pentanoic acid, and n-hexanoic acid; the carboxylic acid ester raw material is selected from dimethyl phthalate, dimethyl terephthalate, methyl glutarate, methyl adipate, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl 1,3-cyclohexanedicarboxylate, dimethyl isophthalate, and methacrylate.

[0067] Preferably, the molar ratio of the carboxylic acid or carboxylic acid ester to ammonia is 1:1-1:20, preferably 1:3-1:10.

[0068] Preferably, the reaction temperature of the continuous amination and dehydration reaction device 11 is 200-400° C., and the reaction pressure is 0.05-0.8 MPa.

[0069] Preferably, the hydrogen-nitrile molar ratio of the catalytic hydrogenation reaction unit 31 is 5-300:1, preferably 50-160:1.

[0070] Preferably, the reaction temperature of the catalytic hydrogenation reaction device 31 is 60-200° C., and the reaction pressure is 0.5-6 MPa.

[0071] Preferably, the solvent of the catalytic hydrogenation reaction device 31 includes but is not limited to alcohols and aromatic hydrocarbons, such as methanol, ethanol, isobutanol, toluene, etc.

[0072] Preferably, the catalyst for preparing nitrile compounds by ammoniation and dehydration is mainly a solid acid catalyst, including but not limited to one or more of silicon dioxide, γ-alumina, zirconium dioxide, cerium dioxide, tungsten trioxide, niobium pentoxide, zeolite molecular sieve, and ion exchange resin.

[0073] Preferably, the catalytic hydrogenation catalyst for preparing organic amines includes but is not limited to precious metal palladium-based catalysts, ruthenium-based catalysts, platinum-based catalysts, non-precious metal nickel-based catalysts, cobalt-based catalysts, iron-based catalysts and copper-based catalysts.

[0074] Reference below Figure 1 The specific operation mode of the green synthesis system according to the utility model is specifically described, including the following steps:

[0075] 1) The raw carboxylic acid or carboxylic acid ester enters the preheating device 12 in the nitrile synthesis unit and is preheated to a temperature close to the reaction temperature. At the same time, the fresh ammonia and the circulating ammonia are also preheated to a temperature close to the reaction temperature after being mixed. Then, the two enter the continuous amination and dehydration reaction device 11; (When the reactor of the continuous amination and dehydration reaction device 11 is a fluidized bed, the raw carboxylic acid or carboxylic acid ester can be directly introduced into the reactor without preheating;)

[0076] 2) In the continuous ammoniation and dehydration reaction device 11, the reaction temperature is controlled to be 160-400° C. and the reaction pressure is 0.05-0.8 MPa. The carboxylic acid or carboxylic acid ester in step 1 undergoes an ammoniation and dehydration reaction under the action of a catalyst to produce a gas-phase nitrile compound. The gas-phase product nitrile and excess ammonia are mixed to form a low-pressure and high-temperature mixed gas;

[0077] 3) the high-temperature mixed gas after the reaction enters the solvent jet device 21 in the ejection unit 2, and the solvent forms a high-speed jet in the solvent jet device 21, thereby entraining the high-temperature and low-pressure mixed gas in step 2), and undergoes intense energy and heat exchange with the mixed gas to form a uniformly dispersed gas-liquid mixture; then continues to enter the hydrogen ejection device 22, where the high-pressure circulating hydrogen from the circulation unit 5 ejects the gas-liquid mixture and mixes intensely with it, and finally obtains a low-temperature and high-pressure reaction raw material that meets the requirements of catalytic hydrogenation, which is usually a highly dispersed gas-liquid mixture; at this time, the gas-liquid mixture contains nitrile solution, ammonia, hydrogen and water vapor, etc., and the pressure is 0.5-6MPa;

[0078] 4) The gas-liquid mixed reaction raw material and fresh hydrogen in step 3) are introduced into the catalytic hydrogenation reaction device 31 in the amine synthesis unit 3. If the raw material temperature does not meet the requirements of the catalytic hydrogenation reaction, a heat exchange device can be added to preheat or cool the raw material temperature. In particular, when the catalytic hydrogenation to produce organic amines is a gas-solid phase reaction, the raw material needs to be completely gasified by a preheater;

[0079] 5) In step 4), the reaction raw materials are placed in a catalytic hydrogenation reaction device 31, where the nitrile compound and hydrogen are reacted with a catalyst to synthesize an organic amine, and the reaction temperature is controlled to be 60-200° C. and the reaction pressure is controlled to be 0.5-6 MPa;

[0080] 6) After step 5) is completed, the reaction material is cooled to below the boiling point of the amine compound by the cooling device 32;

[0081] 7) The material after cooling in step 6) is passed into the gas-liquid two-phase separation device 41 in the separation unit 4 for gas-liquid separation, and the obtained liquid phase is the crude amine solution, and the unreacted hydrogen and ammonia gas phase mixture enters the circulation unit 5.

[0082] 8) In step 7), the gas mixture is separated from the mixed gas by industrial hydrogen membrane separation in the membrane separation device 51 of the circulation unit 5, and the hydrogen is pressurized to 3-15 MPa by the hydrogen booster 52 and returned to the hydrogen ejector 21 as circulating hydrogen; the separated mixed gas mainly contains ammonia, which is introduced into the ammonia pressure reducing device 53, dried by adsorption, and then reduced to 0.3-0.9 MPa, and returned to the nitrile synthesis unit 1 as circulating ammonia for recycling.

[0083] Embodiment 1:

[0084] 1) glutaric acid and ammonia are respectively fed into a pilot fluidized bed nitrile synthesis unit 1 to prepare glutaronitrile, wherein glutaric acid is a solid raw material and is directly fed into the continuous ammoniation and dehydration device 11 by a feeding mechanism without preheating, and the feeding rate is 15.84 kg / h. Ammonia is prepared according to a molar ratio of glutaric acid to ammonia of 1:3, and the ammonia passes through the heat exchange device 12, is preheated to 300-350° C. and enters the continuous ammoniation and dehydration device 11;

[0085] 2) In the continuous ammoniation and dehydration device 11, the ammonia in step 1 is also used as a fluidizing gas to fluidize the solid acid catalyst in the reactor, the reaction temperature is controlled to be 300-350° C., the reaction pressure is 0.1-0.3 MPa, glutaric acid is ammoniation and dehydrated to generate a gas phase, and the glutaronitrile gas, unreacted ammonia, and generated water vapor form a high-temperature mixed gas and are output from the gas phase outlet of the ammoniation and dehydration device 11;

[0086] 3) Step 2) The high-temperature mixed gas enters the solvent jet device 21 in the ejection unit 2, and the solvent ethanol enters the solvent jet device 21 at a speed of 60-75 kg / h to form a high-speed jet, so that the high-temperature mixed gas is sucked into the root of the jet, and ethanol and the high-temperature gas undergo intense heat and mass transfer to form a gas-liquid mixture of glutaronitrile alcohol ammonia solution, and the temperature of the mixture is about 70-100° C.;

[0087] 4) The gas-liquid mixture in step 3) continues to enter the hydrogen ejector 22, the high-pressure circulating hydrogen from the circulation unit 5 has a pressure of about 2.5-3 MPa, and the hydrogen flow rate is matched according to a molar ratio of glutaric acid to hydrogen of about 1:28-32. The high-pressure hydrogen ejects the gas-liquid mixture in the hydrogen ejector, and the hydrogen and the mixture are uniformly mixed after ejection to obtain a highly dispersed gas-liquid mixture containing nitrile, ammonia, water and hydrogen, with a pressure of about 1-1.5 MPa;

[0088] 5) The hydrogen-containing gas-liquid mixture in step 4) is then heated to about 120° C. in a preheater and introduced into the catalytic hydrogenation device 31 in the amine synthesis unit 3 together with fresh hydrogen. The catalytic hydrogenation device 31 is a gas-liquid-solid three-phase reactor. The hydrogen-containing gas-liquid mixture is hydrogenated to produce pentamethylenediamine by glutaronitrile under the action of a skeleton nickel catalyst at 120-140° C. and a pressure of 1 MPa, while producing a small amount of secondary amines and tertiary amines as by-products.

[0089] 6) The reaction liquid in step 5) is cooled to 40-60° C. by the cooling device 32 and then enters the separation unit 4;

[0090] 7) In the gas-liquid separation device 41 of the separation unit 4, the material in step 6 is subjected to gas-liquid separation, and the separated liquid phase is the product crude amine ethanol solution, while the gas phase continues to enter the circulation unit 5;

[0091] 8) The gas phase in step 7) mainly contains hydrogen, ammonia, a small amount of water vapor and others, which is passed into the membrane separation device 51, and the hydrogen is separated from other gases by the industrial hydrogen membrane. The separated hydrogen is introduced into the hydrogen booster 52, pressurized to 2.5-3MPa to obtain circulating hydrogen, and the circulating hydrogen returns to step 4 as the ejection gas flow of the hydrogen ejector 22; and the remaining gas mainly contains ammonia, which is directly depressurized after adsorption and drying to remove impurities and water, and returned to the nitrile synthesis unit as circulating ammonia, and participates in the reaction together with fresh ammonia.

[0092] The conversion rate of glutaric acid was 99%, the yield of pentamethylenediamine was 86%, the yield of secondary amine was 8%, and there were a small amount of tertiary amine and unhydrogenated glutaronitrile, as well as other products such as mononitrile.

[0093] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A continuous synthesis system for preparing amine compounds using carboxylic acid or carboxylic acid ester as raw material, mainly include: Nitrile synthesis unit, ejector unit, amine synthesis unit, separation unit, circulation unit; The nitrile synthesis unit mainly comprises a preheating device and a continuous ammoniation and dehydration reaction device connected in sequence, wherein the preheating device is used to preheat the raw material carboxylic acid or carboxylate and the raw material gas ammonia respectively, and the continuous ammoniation and dehydration reaction device is located downstream of the nitrile synthesis unit and connected by a pipeline, receives the reaction materials from the preheating device and mainly comprises an ammoniation and dehydration reactor, and the preheated carboxylic acid or carboxylate and ammonia react catalytically in the ammoniation and dehydration reactor to synthesize nitrile compounds, and the product is a high-temperature mixed gas composed of the generated gas-phase nitrile compounds and unreacted ammonia and water vapor; The ejector unit is located downstream of the continuous ammoniation and dehydration reaction device and connected via a pipeline, and mainly comprises a solvent ejector and a hydrogen ejector, and is used to receive the high-temperature mixed gas containing nitrile produced by the nitrile synthesis unit, wherein the solvent ejector ejects a solvent to the high-temperature mixed gas containing nitrile, and the hydrogen ejector is located downstream of the solvent ejector, and is used to eject high-pressure hydrogen to the high-temperature mixed gas containing nitrile to form a high-pressure and low-temperature catalytic hydrogenation reaction raw material mixture; The amine synthesis unit is located downstream of the ejector unit and connected by a pipeline, and includes a catalytic hydrogenation reaction device and a cooling device. The catalytic hydrogenation reaction device mainly includes a hydrogenation reactor, and the mixed reaction materials transported from the ejector unit and fresh hydrogen are subjected to catalytic hydrogenation reaction in the hydrogenation reactor to synthesize organic amine compounds; the cooling device is located downstream of the catalytic hydrogenation reaction device and is used to cool the mixed materials after the catalytic hydrogenation reaction; The separation unit is located downstream of the amine synthesis unit and connected via a pipeline, and includes a gas-liquid two-phase separation device, which receives the cooled mixed material from the amine synthesis unit and obtains a liquid crude amine solution after two-phase separation; The circulation unit is connected to the preheating device, the hydrogen ejector device and the gas-liquid separation device through a pipeline, and mainly includes a membrane separation device, a hydrogen booster device and an ammonia pressure reducing device, and is used to receive the mixed gas from the separation unit, separate and adjust the pressure of the mixed gas, and recycle the hydrogen and ammonia respectively, wherein the membrane separation device is mainly used to separate the hydrogen from the ammonia in the mixed gas; The hydrogen booster device is used to receive the hydrogen from the membrane separation device and circulate it back to the hydrogen ejector device after boosting the pressure; The ammonia pressure reducing device is used to receive ammonia from the gas membrane separation device and reduce the pressure to circulate back to the nitrile synthesis unit, and then continue to be used for synthesizing nitrile compounds after being mixed with fresh ammonia.

2. The continuous synthesis system according to claim 1, It is characterized in that The preheating device is a heat exchanger group, and the connection form is parallel, series, or a combination of series and parallel. The specific equipment forms include shell and tube heat exchangers, electric heating heat exchangers, and heating furnaces.

3. The continuous synthesis system according to claim 1, It is characterized in that The ammoniation and dehydration reactor in the continuous ammoniation and dehydration reaction device is a fixed bed reactor or a fluidized bed reactor; when a fluidized bed reactor is used, the raw material can be directly fed without preheating when it is solid or liquid.

4. The continuous synthesis system according to claim 1, It is characterized in that The solvent injection device adopts a jet pump; the hydrogen injection device adopts a Laval tube or a Venturi structure, and the hydrogen injection device is a single-stage injection or a multi-stage injection, and the number of stages is one to three.

5. The continuous synthesis system according to claim 1, It is characterized in that The hydrogenation reactor in the catalytic hydrogenation reaction device includes a fixed bed reactor, a trickle bed reactor and a tubular reactor; when the catalytic hydrogenation reaction is a gas-solid phase reaction, a preheater is added in front of the reactor to completely gasify the mixed raw materials before introducing them into the reactor.

6. The continuous synthesis system according to claim 1, It is characterized in that The membrane separation device adopts industrial hydrogen membrane separation equipment.

7. The continuous synthesis system according to claim 1, It is characterized in that The hydrogen boosting device comprises a hydrogen compressor.

8. The continuous synthesis system according to claim 1, It is characterized in that The ammonia pressure reducing device mainly includes adsorption, drying equipment and pressure reducing equipment, and the pressure reducing equipment includes a pressure reducing valve, a throttling orifice plate and an expander.

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