Continuous device and method for preparing glycine

Abstract

The present invention provides a continuous device and method for preparing glycine. The continuous device includes: an amination reaction unit, a post-processing unit and a control unit; the amination reaction unit and the post-processing unit are arranged in series, and the control unit regulates the amination reaction unit and the post-processing unit through an electrical signal; the amination reaction unit includes a continuous feeding module, a continuous mixing module and a continuous amination reaction module arranged in series in sequence; the continuous amination reaction module includes: a continuous amination reactor; a liquid reactant feed port located at the upper part and a gas reactant feed port located at the lower part are arranged on the side of the continuous amination reactor; a continuous dispersion module is arranged below the liquid reactant feed port inside the continuous amination reactor for dispersing the liquid reactant into droplets. By adopting the continuous reaction device, each unit is automated, and the provision of a continuous dispersion module can further improve the reaction efficiency and the yield of glycine.

Description

Technical Field

[0001] The present invention relates to the technical field of amino acid industrial production, and in particular to a continuous device and method for preparing glycine. Background Art

[0002] Glycine, also known as aminoacetic acid, is an important fine chemical intermediate and chemical raw material, widely used in the fields of pesticide glyphosate, medicine, food and feed additives. The existing industrial production process of glycine still uses the traditional chloroacetic acid ammonolysis method with water as solvent, such as Figure 3 As shown, the current aqueous phase synthesis route adopts an intermittent process, and the reactor adopts an intermittent stirred tank. The catalyst urotropine is prepared into an aqueous solution and first added to the reactor, and then the chloroacetic acid solution and ammonia gas are simultaneously introduced into the reactor at a certain flow rate, and an amination reaction occurs in the reactor. After that, the feed liquid (synthetic liquid) enters the alcohol precipitation pot, and a large amount of methanol is added for alcohol precipitation, and then centrifuged to obtain glycine crude product (containing a small amount of ammonium chloride and urotropine) and glycine mother liquor. The glycine crude product is washed, centrifuged, and dried to obtain the glycine product; the glycine mother liquor is rectified by a distillation tower to recover the methanol therein, and then concentrated, crystallized, and centrifuged to obtain ammonium chloride crystals and ammonium chloride mother liquor.

[0003] Although existing glycine companies have tried their best to optimize the aqueous phase process, they still cannot fundamentally solve the process defects and there is also a large environmental pollution problem. The above method has the following problems: (1) High production cost. The catalyst urotropine cannot be recycled; 1 ton of glycine requires about 6-7 tons of steam; when recycling low-value-added ammonium chloride, the equipment and pipeline requirements are high, the maintenance frequency is high, and the equipment operation and maintenance costs are high. (2) The yield is low and it is difficult to exceed 85%. The system in the aqueous phase is highly alkaline, and the conversion rate of chloroacetic acid to glycine is low. About 15% of chloroacetic acid is hydrolyzed to produce hydroxyacetic acid; when high-temperature ammonia is insufficient, it is easy to produce iminodiacetic acid [NH(CH2COOH) 2 ] and aminotriacetic acid [N(CH2COOH) 3 ] and other by-products. (3) Environmental risks cannot be completely eliminated. Problems such as the decomposition of ammonium chloride and the catalyst urotropine at high temperatures, as well as complex chemical reactions caused by high temperatures, will produce evaporated condensed water and red filtrate with high ammonia nitrogen and high COD. In addition, there are hazardous wastes (ammonium dichloroacetate, ammonium trichloroacetate, urotropine, etc.) in low-purity ammonium chloride products, which do not comply with relevant national regulations. The current disposal method has legal risks. (4) The production process is mostly intermittent reaction, and each step is cumbersome. There are disadvantages such as low production efficiency, unstable product quality, poor safety, poor heat transfer in intermittent reactions, huge waste of ammonia, and limited production capacity.

[0004] Under the current environment of thin profits for glycine enterprises, glycine enterprises cannot completely abandon the aqueous phase process equipment, invest large amounts of money to build new process equipment, and carry out transformation on the existing equipment.

[0005] Therefore, the present application intends to provide a preparation device and method capable of improving the yield and purity of glycine. Summary of the invention

[0006] The main purpose of the present invention is to provide a continuous device and method for preparing glycine, so as to solve the problem of poor purity and yield of glycine prepared in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to a first aspect of the present invention, there is provided a continuous device for preparing glycine, the continuous device comprising: an amination reaction unit, a post-treatment unit and a control unit; the amination reaction unit and the post-treatment unit are arranged in series, and the control unit regulates the amination reaction unit and the post-treatment unit through an electrical signal; the amination reaction unit comprises a continuous feeding module, a continuous mixing module and a continuous amination reaction module which are arranged in series in sequence; wherein the continuous amination reaction module comprises: a continuous amination reactor; a liquid reactant feed inlet located at the upper part and a gas reactant feed inlet located at the lower part are arranged on the side of the continuous amination reactor; a continuous dispersion module is arranged inside the continuous amination reactor below the liquid reactant feed inlet, for dispersing the liquid reactant into droplets.

[0008] Furthermore, the continuous amination reactor further comprises: a heat exchange module, which is arranged outside the continuous amination reactor, and the control unit regulates and controls the heat exchange module and the continuous dispersion module; preferably, the continuous amination reactor further comprises: a pH detection module and a temperature detection module, and the pH detection module and the temperature detection module respectively monitor the pH value and temperature inside the continuous amination reactor in real time, and feed back the detection results to the control unit, and the control unit regulates and controls the parameters of the reaction carried out inside the continuous amination reactor.

[0009] Furthermore, the continuous amination reactor further comprises: a product discharge port and a gas outlet provided with a condensing device, which are respectively arranged at the lower part and the upper part of the continuous amination reactor.

[0010] Furthermore, the continuous amination reaction module further comprises: at least one continuous solid-liquid grading reactor, and the feed inlet of the continuous solid-liquid grading reactor is connected to the continuous amination reactor through a product discharge port.

[0011] Furthermore, the continuous solid-liquid grading reactor is provided with a feed port located at the top; the continuous solid-liquid grading reactor is divided into a solid grading zone and a solid sedimentation zone from top to bottom; preferably, the solid grading zone is a trapezoidal cylindrical structure, and a drum agitator with a cylindrical circulation structure is arranged inside the solid grading zone; preferably, the cross-sectional diameter of the solid grading zone gradually decreases from top to bottom, and preferably, the ratio of the cross-sectional diameter at the top to the cross-sectional diameter at the bottom is (4-2): 1; preferably, a discharge port is arranged at the bottom of the solid sedimentation zone, and a second circulation port is arranged at the side, and the second circulation port is connected to the first circulation port at the side of the solid grading zone through a solid-liquid conveying pump, so that the liquid material inside the solid grading zone and the solid sedimentation zone can be circulated and conveyed.

[0012] Furthermore, the continuous feeding module comprises: a chloroacetic acid feeding module, a urotropine feeding module, an ammonia feeding module and a solvent feeding module; the chloroacetic acid feeding module and the urotropine feeding module are connected in parallel, and their respective material outlets are connected to the material inlet of the continuous mixing module; the material outlet of the solvent feeding module is respectively connected to the material inlets of the chloroacetic acid feeding module and the urotropine feeding module; the material outlet of the ammonia feeding module is connected to the gas reactant feed port of the continuous amination reactor in the continuous amination reaction module.

[0013] Furthermore, the post-processing unit comprises a continuous crystallization module, a continuous filtration module and a continuous drying module which are sequentially connected in series.

[0014] In order to achieve the above object, according to a second aspect of the present invention, a method for preparing glycine using the above continuous device is provided, the method comprising: passing a chloroacetic acid solution and a urotropine solution into a continuous mixing module through a continuous feeding module for mixing to obtain a first liquid reactant; passing the first liquid reactant into a continuous amination reaction module, and carrying out an amination reaction with ammonia gas passed into the continuous amination reaction module through the continuous feeding module in a continuous amination reactor to obtain a crude glycine product; passing the crude glycine product into a post-processing unit for purification to obtain glycine; wherein the first liquid reactant is dispersed into droplets in the continuous amination reactor for an amination reaction.

[0015] Furthermore, chloroacetic acid is mixed with a solvent to obtain a chloroacetic acid solution, and urotropine is mixed with a solvent to obtain a urotropine solution; the mass ratio of chloroacetic acid to the solvent is 1:(0.1-0.3); preferably, the mass ratio of urotropine to the solvent is 1:(0.5-5).

[0016] Furthermore, in the amination reaction, the molar ratio of the urotropine solution, ammonia gas and chloroacetic acid is (0.02-0.05):(2-2.5):1; preferably, the amination reaction time is 5 min-30 min; preferably, the amination reaction pressure is 0.1-0.5 MPa; preferably, the temperature control range of the continuous amination reactor is 65-80°C.

[0017] Furthermore, the particle size of the droplets is 50-800 μm; preferably, the feed flow rates of the first liquid reactant and the ammonia gas are independently 0.1-10 g / min.

[0018] The technical solution of the present invention is applied, a continuous reaction device is adopted, each unit is automated, and the setting of a continuous dispersion module can further improve the reaction efficiency, so as to further improve the yield of glycine, and the reaction raw materials are cheap and easy to obtain, the reaction conditions are stable and mild, and products with stable and uniform quality can be obtained, which is suitable for large-scale industrial production and reduces labor costs. The continuous amination reactor has a large heat exchange area, can quickly transfer the reaction exotherm, realize precise temperature control, and has high reaction selectivity. The technical solution of the present application can greatly reduce the amount of catalyst and solvent, greatly reduce the amount of wastewater generated by the reaction system, and the cost of industrial production, and the process is green and safe, with little environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 A schematic diagram of a continuous reaction device of the present application is shown;

[0021] Figure 2 The schematic diagram of the structure of the continuous amination reactor of the present application is shown;

[0022] Figure 3 A flow chart of an existing batch process in the background technology is shown;

[0023] Figure 4 The schematic diagram of the structure of the continuous solid-liquid fractionation reactor of the present application is shown;

[0024] Among them, the above Figure 1 The following reference numerals are included:

[0025] 1. amination reaction unit, 2. post-processing unit, 3. control unit, 11. feeding module, 111. chloroacetic acid feeding module, 112. urotropine feeding module, 113. ammonia feeding module, 114. solvent feeding module, 12. continuous mixing module, 13. continuous amination reaction module, 21. post-processing module, 211. continuous crystallization module, 212. continuous filtration module, 213. continuous drying module, A. glycine.

[0026] Among them, the above Figure 2 The following reference numerals are included:

[0027] 401, liquid reactant feed port, 402, gas reactant feed port, 403, product discharge port, 404, continuous dispersion module, 405, gas outlet.

[0028] Among them, the above Figure 4 The following reference numerals are included:

[0029] 301. feed port, 302. discharge port, 303. solid settling area, 304. solid classification area, 305. solid-liquid transfer pump. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0031] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0032] In a first typical embodiment of the present application, a continuous device for preparing glycine is provided, the continuous device comprising (such as Figure 1 As shown): an amination reaction unit 1, a post-treatment unit 2 and a control unit 3; the amination reaction unit 1 and the post-treatment unit 2 are arranged in series, and the control unit 3 regulates the amination reaction unit 1 and the post-treatment unit 2 through an electrical signal; the amination reaction unit 1 includes a continuous feeding module 11, a continuous mixing module 12 and a continuous amination reaction module 13 which are arranged in series in sequence; wherein the continuous amination reaction module 13 includes: a continuous amination reactor; a liquid reactant feed port 401 located at the upper part and a gas reactant feed port 402 located at the lower part are arranged on the side of the continuous amination reactor; a continuous dispersion module 404 is arranged inside the continuous amination reactor below the liquid reactant feed port 401, for dispersing the liquid reactant into droplets.

[0033] In order to further control the amination reaction under more efficient reaction conditions, in a preferred embodiment, the continuous amination reactor further includes: a heat exchange module, which is arranged outside the continuous amination reactor, and the control unit 3 regulates the heat exchange module and the continuous dispersion module; preferably, the continuous amination reactor further includes: a pH detection module and a temperature detection module, the pH detection module and the temperature detection module respectively monitor the pH value and temperature inside the continuous amination reactor in real time, and feed back the detection results to the control unit 3, and the control unit 3 regulates the parameters (including feed rate and temperature) of the reaction inside the continuous amination reactor.

[0034] In order to further save the reaction cost, the remaining reactants can be reused. In a preferred embodiment, the continuous amination reactor further comprises: a product discharge port 403 and a gas outlet 405 provided with a condensing device, which are respectively arranged at the lower part and the upper part of the continuous amination reactor (such as Figure 2 as shown).

[0035] In order to further control the amination reaction to be more complete and to separate glycine from the system online to reduce over-reaction impurities, in a preferred embodiment, the continuous amination reaction module 13 also includes: at least one continuous solid-liquid grading reactor, and the feed port 301 of the continuous solid-liquid grading reactor is connected to the continuous amination reactor through the product discharge port 403.

[0036] The solid crude glycine product and the remaining liquid reactants in the reaction system are discharged from the continuous ammoniation reactor and enter the continuous solid-liquid fractionation reactor to complete the remaining unfinished ammoniation reaction, and the glycine solid is separated from the continuous ammoniation reactor in real time, thereby reducing the impurities such as iminodiacetic acid and aminotriacetic acid generated by the continuous reaction of the glycine product with chloroacetic acid in the continuous ammoniation reactor. In a preferred embodiment, Figure 4 As shown, the continuous solid-liquid grading reactor is provided with a feed inlet 301 located at the upper part; the continuous solid-liquid grading reactor is divided into a solid grading zone 304 and a solid settling zone 303 from top to bottom; the solid grading zone 304 is a trapezoidal cylindrical structure, and a drum agitator with a cylindrical circulation structure is arranged inside the solid grading zone 304; the cross-sectional diameter of the solid grading zone 304 gradually decreases from top to bottom, and the ratio of the cross-sectional diameter at the top to the cross-sectional diameter at the bottom is (4-2): 1; a discharge port 302 is arranged at the bottom of the solid settling zone 303, and a second circulation port is arranged at the side, and the second circulation port is connected to the first circulation port at the side of the solid grading zone 304 through a solid-liquid conveying pump 305, so that the materials inside the solid grading zone 304 and the solid settling zone 303 can be circulated and conveyed.

[0037] The ammoniation reaction system (solid-liquid mixture) containing the remaining raw material chloroacetic acid discharged from the continuous ammoniation reactor enters the continuous solid-liquid classification reactor, wherein the product glycine solid passes through the solid classification zone 304, and is enriched from the solution system from top to bottom along the inclined surface of the reactor wall of the trapezoidal cylindrical structure under the action of gravity and the stirring of the drum agitator, and passes through the solid sedimentation zone 303, and is separated from the reaction system from the bottom. The liquid reaction system containing unreacted chloroacetic acid, hexamethylenetetramine and ammonia enters the solid classification zone 304 again through the solid-liquid delivery pump 305 to continue the reaction, thereby completely converting the remaining raw materials.

[0038] In a preferred embodiment, a solid-liquid delivery pump 305 is provided between the discharge port 302 and the bottom of the solid settling zone 303. In a preferred embodiment, when there are multiple continuous solid-liquid grading reactors, the discharge port 302 of the first continuous solid-liquid grading reactor is connected to the feed port 301 of the next continuous solid-liquid grading reactor, and the discharge port 302 of the last continuous solid-liquid grading reactor is connected to the continuous crystallization module 211.

[0039] In order to further efficiently control the amount of reactants added, control the reaction cost and reaction efficiency, in a preferred embodiment, the continuous feeding module 11 includes: a chloroacetic acid feeding module 111, a urotropine feeding module 112, an ammonia feeding module 113 and a solvent feeding module 114; the chloroacetic acid feeding module 111 and the urotropine feeding module 112 are connected in parallel, and their respective material outlets are connected to the material inlet of the continuous mixing module 12; the material outlet of the solvent feeding module 114 is respectively connected to the material inlets of the chloroacetic acid feeding module 111 and the urotropine feeding module 112; the material outlet of the ammonia feeding module 113 is connected to the gas reactant feed port 402 of the continuous amination reactor in the continuous amination reaction module 13.

[0040] To further improve the post-processing efficiency of the crude glycine, in a preferred embodiment, the post-processing unit 2 includes a continuous crystallization module 211, a continuous filtration module 212 and a continuous drying module 213 which are sequentially connected in series.

[0041] In a second typical embodiment of the present application, a method for preparing glycine using the above-mentioned continuous device is provided, the method comprising: passing a chloroacetic acid solution and a urotropine solution into a continuous mixing module 12 through a continuous feeding module 11 respectively for mixing to obtain a first liquid reactant; passing the first liquid reactant into a continuous amination reaction module 13, and carrying out an amination reaction with ammonia gas passed into the continuous amination reaction module 13 through the continuous feeding module 11 in a continuous amination reactor to obtain a crude glycine product; passing the crude glycine product into a post-processing unit 2 for purification to obtain glycine; wherein the first liquid reactant is dispersed into droplets in the continuous amination reactor for an amination reaction.

[0042] In order to further efficiently carry out the amination reaction, in a preferred embodiment, acetic acid is mixed with a solvent to obtain a chloroacetic acid solution, and hexamethylenetetramine is mixed with a solvent to obtain a hexamethylenetetramine solution; preferably, the mass ratio of chloroacetic acid to solvent is 1:(0.1-0.3); preferably, the mass ratio of hexamethylenetetramine to solvent is 1:(0.5-5); preferably, the solvent includes: water or an aqueous solution of a C1-C5 alcohol. Preferably, in the aqueous solution of a C1-C5 alcohol, the volume ratio of alcohol to water is 1:(6-15).

[0043] In order to further efficiently carry out the amination reaction, in a preferred embodiment, in the amination reaction, the molar ratio of the urotropine solution, ammonia gas and chloroacetic acid is (0.02-0.05): (2-2.5): 1; preferably, the amination reaction time is 5min-30min; preferably, the amination reaction pressure is 0.1-0.5Mpa; preferably, the temperature control range of the continuous amination reactor is 65-80°C. Preferably, the temperature control range of the continuous solid-liquid classification reactor is 50-70°C.

[0044] To further efficiently carry out the amination reaction, in a preferred embodiment, the particle size of the droplets is 50-800 μm; preferably, the feed flow rates of the first liquid reactant and the ammonia gas are independently 0.1-10 g / min.

[0045] Example 1

[0046] The continuous reaction device of the present application is subjected to a 0-1MPa air tightness test using nitrogen. If the pressure drop is less than 0.01MPa after 2 hours, it is qualified.

[0047] The reactants are continuously added through the continuous feeding module 11 of the ammoniation reaction unit 1. Water is introduced into the chloroacetic acid feeding module 111 and the urotropine feeding module 112 in the solvent feeding module 114, and mixed with chloroacetic acid and urotropine to obtain chloroacetic acid solution and urotropine solution. Then, the chloroacetic acid solution and the urotropine solution are introduced into the continuous mixing module 12 through the chloroacetic acid feeding module 111 and the urotropine feeding module 112 to mix and obtain the first liquid reactant.

[0048] The mass ratio of chloroacetic acid to water is 1:0.3, and the mass ratio of hexamethylenetetramine to water is 1:4. The mixing temperature in the continuous mixing module 12 is 65°C.

[0049] Ammonia gas enters the continuous amination reactor of the continuous amination reaction module 13 from the gas reactant feed port 402 through the continuous ammonia feeding module 113, and the chloroacetic acid solution and the urotropine solution enter the continuous amination reactor of the continuous amination reaction module 13 from the liquid reactant feed port 401 through the continuous mixing module 12, and are dispersed into droplets of 50-800 μm by the continuous dispersion module 404 in the continuous amination reactor, and react with ammonia gas to react, and the product flows through the subsequent two continuous solid-liquid classification reactors to complete the amination reaction, thereby obtaining crude glycine.

[0050] Among them, the temperature is adjusted by the heat exchange module, the chloroacetic acid solution and the urotropine solution are condensed at low temperature, the remaining ammonia gas is separated from the liquid phase, and discharged through the gas outlet 405, and can be subsequently passed into the continuous solid-liquid grading reactor to continue the reaction completely; during the amination reaction of the continuous amination reactor, the reaction temperature and pH value can be monitored and adjusted in real time through the pH online detection module and the temperature monitoring module. The molar ratio of the urotropine solution, ammonia gas and chloroacetic acid is 0.02:2.0:1. The amination reaction temperature is 70°C, the reaction time is 30min, the reaction pressure is 0.2.Mpa, and the reaction pH value is 6.0-6.5. The feed flow rate of the first liquid reactant is 27.49g / min, and the feed flow rate of ammonia gas is 9.27g / min.

[0051] The product obtained in the continuous ammoniation reactor and the incompletely reacted liquid reactant are discharged through the product discharge port 403, and enter the continuous solid-liquid grading reactor through the feed port 301 of the continuous solid-liquid grading reactor. The incompletely reacted chloroacetic acid, hexamethylenetetramine and ammonia complete the remaining ammoniation reaction in the solid grading zone 304. The product glycine solid is separated from the solid by the drum agitator therein and enters the solid sedimentation zone 303. The liquid reaction system is recirculated into the solid grading zone 304 through the solid-liquid delivery pump 305. The solid is discharged from the discharge port 302 through the solid-liquid delivery pump 305 and enters the next continuous solid-liquid grading reactor. The above process is repeated and the product is discharged from the discharge port 302 of the second continuous solid-liquid grading reactor to obtain crude glycine.

[0052] The crude glycine product is sequentially introduced into the continuous crystallization module 211, the continuous filtration module 212 and the continuous drying module 213 in the post-processing module 21 of the post-processing unit 2 for sequential crystallization, filtration and drying purification to obtain glycine A.

[0053] The control unit 3 is used to control the feed flow rate and temperature in each module.

[0054] The purity and total yield of the obtained glycine were detected and calculated using a liquid phase external standard detection method, and the purity was 99.6% and the total yield was 99.7%.

[0055] Example 2

[0056] Except for the amination reaction temperature in this example, which is different from that in Example 1, the other operations are the same as those in Example 1, and the amination reaction temperature in this example is 65° C. The purity of the obtained glycine is 97.4%, and the total yield is 96.5%.

[0057] Example 3

[0058] Except for the amination reaction temperature in this example, which is different from that in Example 1, the other operations are the same as those in Example 1, and the amination reaction temperature in this example is 80° C. The purity of the obtained glycine is 95.3%, and the total yield is 94.1%.

[0059] Comparative Example 1

[0060] This comparative example was carried out in batches.

[0061] First, add the urotropine aqueous solution into a four-necked bottle, and add the chloroacetic acid aqueous solution dropwise while ammonia is introduced into the reaction system. The reaction temperature is controlled at 80°C, the molar ratio of urotropine solution, ammonia and chloroacetic acid is 0.02:2.0:1, the mass ratio of chloroacetic acid to water is 1:0.3, and the mass ratio of urotropine to water is 1:4. The dropping time is controlled at 90-120min, and the reaction is kept warm for 2h after the dropping is completed, so that the raw material chloroacetic acid is completely converted. Glycine A is obtained by post-treatment separation, and the product purity is detected to be 73.1%, and the total yield is 65.3%.

[0062] Comparative Example 2

[0063] This comparative example was carried out in batches.

[0064] First, add the urotropine aqueous solution into a four-necked bottle, and add the chloroacetic acid aqueous solution dropwise while introducing ammonia into the reaction system, control the reaction temperature at 80°C, the molar ratio of the urotropine solution, ammonia and chloroacetic acid is 0.02:2.0:1, the mass ratio of chloroacetic acid to water is 1:1, the mass ratio of urotropine to water is 1:10, the dropping time is controlled at 90-120min, and the reaction is kept warm for 2h after the dropping is completed, so that the raw material chloroacetic acid is completely converted. Glycine A is obtained by post-treatment separation, and the product purity is detected to be 75.1%, and the total yield is 68.5%.

[0065] Comparative Example 3

[0066] This comparative example was carried out in batches.

[0067] First, add the urotropine aqueous solution into a four-necked bottle, and add the chloroacetic acid aqueous solution dropwise while introducing ammonia into the reaction system, control the reaction temperature at 80°C, the molar ratio of the urotropine solution, ammonia and chloroacetic acid is 0.2:3.0:1, the mass ratio of chloroacetic acid to water is 1:1, the mass ratio of urotropine to water is 1:10, the dropping time is controlled at 90-120min, and the reaction is kept warm for 2h after the dropping is completed, so that the raw material chloroacetic acid is completely converted. Glycine A is obtained by post-treatment separation, and the product purity is detected to be 83.1%, and the total yield is 75.5%.

[0068] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: a continuous reaction device is adopted, each unit is automated, the yield of glycine is high, and the reaction raw materials are cheap and easy to obtain, the reaction conditions are stable and mild, and products with stable and uniform quality can be obtained, which is suitable for large-scale industrial production. The labor cost is reduced, and the continuous amination reactor has a large heat exchange area, which can quickly transfer the reaction exotherm, achieve precise temperature control, and have high reaction selectivity. The technical solution of the present application can greatly reduce the amount of catalyst and solvent used, greatly reduce the amount of wastewater generated by the reaction system, and the cost of industrial production, and the process is green and safe, with little environmental pollution.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A continuous device for preparing glycine, characterized in that: The continuous device comprises: An amination reaction unit (1), a post-treatment unit (2) and a control unit (3); The amination reaction unit (1) and the post-treatment unit (2) are arranged in series, and the control unit (3) regulates the amination reaction unit (1) and the post-treatment unit (2) through electrical signals; The amination reaction unit (1) comprises a continuous feeding module (11), a continuous mixing module (12) and a continuous amination reaction module (13) which are sequentially arranged in series; Wherein, the continuous amination reaction module (13) comprises: a continuous amination reactor; The side of the continuous amination reactor is provided with a liquid reactant feed inlet (401) located at the upper part and a gas reactant feed inlet (402) located at the lower part; A continuous dispersion module (404) is provided inside the continuous amination reactor below the liquid reactant feed port (401) for dispersing the liquid reactant into droplets.

2. The continuous device according to claim 1, characterized in that: The continuous amination reactor also includes: A heat exchange module is arranged outside the continuous amination reactor, and the control unit (3) regulates the heat exchange module and the continuous dispersion module; The continuous amination reactor further comprises: a pH detection module and a temperature detection module, wherein the pH detection module and the temperature detection module respectively monitor the pH value and the temperature inside the continuous amination reactor in real time, and feed back the detection results to the control unit (3), and the control unit (3) regulates the parameters of the reaction inside the continuous amination reactor.

3. The continuous device according to claim 1, characterized in that: The continuous amination reactor further comprises: a product discharge port (403) and a gas outlet (405) provided with a condensing device, which are respectively arranged at the lower part and the upper part of the continuous amination reactor.

4. The continuous device according to claim 3, characterized in that: The continuous amination reaction module (13) further comprises: at least one continuous solid-liquid grading reactor, wherein the feed inlet (301) of the continuous solid-liquid grading reactor is connected to the continuous amination reactor via the product discharge port (403).

5. The continuous device according to claim 4, characterized in that: The continuous solid-liquid classification reactor is provided with a feed inlet (301) located at the upper part; The continuous solid-liquid classification reactor is divided into a solid classification zone (304) and a solid sedimentation zone (303) from top to bottom; The solid classification zone (304) is a trapezoidal cylindrical structure, and a drum-type agitator with a cylindrical circulation structure is arranged inside the solid classification zone (304); The cross-sectional diameter of the solid classification zone (304) gradually decreases from top to bottom, and the ratio of the cross-sectional diameter at the top to the cross-sectional diameter at the bottom is (4-2):1; The solid settling zone (303) is provided with a discharge port (302) at the bottom and a second circulation port at the side. The second circulation port is connected to the first circulation port at the side of the solid classification zone (304) through the solid-liquid conveying pump (305), so that the liquid material inside the solid classification zone (304) and the solid settling zone (303) can be circulated and conveyed.

6. The continuous device according to claim 1, characterized in that: The continuous feeding module (11) comprises: A chloroacetic acid feed module (111), a urotropine feed module (112), an ammonia feed module (113) and a solvent feed module (114); The chloroacetic acid feeding module (111) and the hexamethylenetetramine feeding module (112) are connected in parallel, and their respective material outlets are connected to the material inlet of the continuous mixing module (12); The material outlet of the solvent feed module (114) is respectively connected to the material inlet of the chloroacetic acid feed module (111) and the hexamethylenetetramine feed module (112); The material outlet of the ammonia feed module (113) is connected to the gas reactant feed port (402) of the continuous amination reactor in the continuous amination reaction module (13).

7. The continuous device according to claim 1, characterized in that: The post-processing unit (2) comprises a continuous crystallization module (211), a continuous filtration module (212), and a continuous drying module (213) which are sequentially connected in series.

8. A method for preparing glycine using the continuous device according to any one of claims 1 to 7, characterized in that: The method comprises: The chloroacetic acid solution and the urotropine solution are respectively introduced into the continuous mixing module (12) through the continuous feeding module (11) for mixing to obtain a first liquid reactant; The first liquid reactant is introduced into the continuous amination reaction module (13), and the ammonia gas introduced into the continuous amination reaction module (13) through the continuous feeding module (11) is reacted with the ammonia gas in the continuous amination reaction reactor to obtain crude glycine; Passing the crude glycine into the post-processing unit (2) for purification to obtain the glycine; Wherein, the first liquid reactant is dispersed into droplets in the continuous amination reactor to carry out the amination reaction.

9. The method according to claim 8, characterized in that Chloroacetic acid is mixed with a solvent to obtain the chloroacetic acid solution, and hexamethylenetetramine is mixed with the solvent to obtain the hexamethylenetetramine solution; The mass ratio of the chloroacetic acid to the solvent is 1:(0.1-0.3); The mass ratio of the hexamethylenetetramine to the solvent is 1:(0.5-5).

10. The method according to claim 8, characterized in that In the amination reaction, the molar ratio of the urotropine solution, the ammonia gas and the chloroacetic acid is (0.02-0.05): (2-2.5): 1; The amination reaction time is 5min-30min; The pressure of the amination reaction is 0.1-0.5Mpa; The temperature control range of the continuous amination reactor is 65-80°C.

11. The method according to claim 8, characterized in that The particle size of the droplets is 50-800 μm; The feed flow rates of the first liquid reactant and the ammonia gas are independently 0.1-10 g / min.

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