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CN-117534598-B - Method for preparing thiodipropionic acid by using series dynamic kettle type reactor

CN117534598BCN 117534598 BCN117534598 BCN 117534598BCN-117534598-B

Abstract

The invention discloses a method for preparing thiodipropionic acid by utilizing serial dynamic kettle reactors, which comprises the steps of preparing S1 reaction liquid, S2 feeding, S3 heat exchange, S4 stay and S5 discharging, wherein after the reaction stays for a certain time, the materials are discharged out of a first dynamic kettle reactor and enter a second dynamic kettle reactor, and further acidizing reaction is carried out to obtain thiodipropionic acid feed liquid. The preparation method can effectively solve the problems of high acrylic acid polymer content, low raw material conversion rate, low yield, safety risk and the like in the traditional process, and generally utilizes a batch reactor to prepare the thiodipropionic acid in the prior art.

Inventors

  • WANG AIFA
  • LI JIE
  • HAN JING

Assignees

  • 天津力生化工有限公司

Dates

Publication Date
20260508
Application Date
20231108

Claims (10)

  1. 1. A method for preparing thiodipropionic acid by using a series dynamic kettle reactor, which is characterized by comprising the following steps: s1, preparing a reaction solution, namely preparing sodium sulfide and sodium hydroxide into aqueous solutions respectively, and adjusting the content of the aqueous solution of the sodium sulfide to 27-29% and the concentration of the sodium hydroxide solution to 25-30% according to experimental requirements; S2, feeding, namely respectively feeding 27-29% sodium sulfide aqueous solution, sodium hydroxide aqueous solution and acrylic acid into a reactor, adjusting the proportion of two-phase raw materials, controlling the feeding mole ratio of sodium sulfide to acrylic acid to be 1:2.03, feeding the mixture into a reaction zone of a first dynamic kettle-type reactor (1) at normal temperature through a pump, controlling the feeding speed of the materials, feeding the sodium hydroxide aqueous solution as another phase material into the first dynamic kettle-type reactor (1) at normal temperature through the pump to adjust the PH value, feeding the sulfuric acid solution as another phase material into a second dynamic kettle-type reactor (2) at normal temperature through the pump, controlling the feeding speed of the two-phase material, controlling the feeding mole ratio of the two-phase material to the material of the first dynamic kettle-type reactor (1) to be 1:1, detecting the temperature and the PH value at any time online or offline, and adjusting the feeding amount of the sulfuric acid solution according to the PH value; S3, heat exchange, namely controlling the temperature by using a temperature controller in the reaction process, so that the reaction temperature in the first step is kept between 70 ℃ and 80 ℃; S4, stopping, namely after the two-phase materials are mixed, the stopping time of the reaction solution is 60-600S, and the reaction is mixed under normal pressure; S5, discharging, namely discharging the material out of the first dynamic kettle-type reactor (1) after the reaction is stopped for a certain time, and entering the second dynamic kettle-type reactor (2), and further performing an acidification reaction to obtain the thiodipropionic acid feed liquid.
  2. 2. The method for preparing thiodipropionic acid by using a series dynamic kettle type reactor according to claim 1, wherein the reactor in S2 comprises a first dynamic kettle type reactor (1) and a second dynamic kettle type reactor (2), built-in coils (3) are arranged outside the first dynamic kettle type reactor (1) and the second dynamic kettle type reactor (2), the built-in coils (3) keep a constant temperature system of the first dynamic kettle type reactor (1) and the second dynamic kettle type reactor (2) through a heat exchange mechanism, the bottoms of the first dynamic kettle type reactor (1) and the second dynamic kettle type reactor (2) are respectively provided with a first reaction zone (4) and a second reaction zone (19), motors (14) are arranged on the first dynamic kettle type reactor (1) and the second dynamic kettle type reactor (2), motors (15) are arranged on the first dynamic kettle type reactor (1) and the second dynamic kettle type reactor (2), a shaft lever (15) is fixedly connected with the first dynamic kettle type reactor (15) and the second dynamic kettle type reactor (2), and the shaft lever (15) is fixedly connected with the first stirring zone (15) and the second stirring zone (15) is fixedly connected with the shaft lever (15) The second dynamic kettle reactor (2) is connected through a conveying pipe (26).
  3. 3. The method for preparing thiodipropionic acid by using the dynamic kettle reactors in series according to claim 1, wherein the first dynamic kettle reactor (1) and the second dynamic kettle reactor (2) are respectively provided with a temperature sensor (12) and a PH value sensor (13).
  4. 4. The method for preparing thiodipropionic acid by using the series dynamic kettle type reactor according to claim 1, wherein the heat exchange mechanism comprises a heat exchange box (11), a heat exchange piece (22) is arranged in the heat exchange box (11), a water pump (7) is arranged on the heat exchange box (11), a spiral pipe (27) is arranged on the built-in coil (3) in an embedded manner, a liquid outlet pipe (5) and a liquid inlet pipe (6) are respectively arranged at two ends of the spiral pipe (27), the liquid outlet pipe (5) is connected with the heat exchange box (11), the liquid inlet end of the water pump (7) is connected with the heat exchange box (11), and the liquid inlet pipe (6) is connected with the liquid outlet end of the water pump (7).
  5. 5. A method for preparing thiodipropionic acid using a series of dynamic tank reactors according to claim 1, wherein the first dynamic tank reactor (1) is provided with a first material inlet pipe (16), a second material inlet pipe (17) and a third material inlet pipe (18).
  6. 6. A method for the preparation of thiodipropionic acid using a series of dynamic tank reactors according to claim 1, characterized in that the second dynamic tank reactor (2) is equipped with a fourth material inlet pipe (9) and a product outlet pipe (8).
  7. 7. The method for preparing thiodipropionic acid by using the dynamic kettle reactors in series according to claim 1, wherein the inner surfaces of the first dynamic kettle reactor (1) and the second dynamic kettle reactor (2) are arranged in a cylindrical structure.
  8. 8. The method for preparing thiodipropionic acid by using the dynamic kettle reactor in series according to claim 1, wherein the first material inlet pipe (16), the second material inlet pipe (17), the third material inlet pipe (18), the fourth material inlet pipe (9) and the product outlet pipe (8) are respectively provided with flow valves.
  9. 9. The method for preparing the thiodipropionic acid by using the serial dynamic kettle reactors according to claim 1, wherein four fixing rods (21) are arranged in each of the first dynamic kettle reactor (1) and the second dynamic kettle reactor (2), a guide cylinder (20) is fixed at the upper end of each fixing rod (21), a shaft rod (15) extends into the guide cylinder (20), and a plurality of fan blades (28) are fixed on the shaft rod (15).
  10. 10. The method for preparing thiodipropionic acid by using the series dynamic kettle type reactor according to claim 4, wherein a power motor (23) is installed at the bottom of the heat exchange box (11), a driving rod (24) is fixedly connected to the output end of the power motor (23), the driving rod (24) penetrates through the heat exchange box (11) and is rotatably connected with the heat exchange box, and a plurality of stirring rods (25) are fixed on the driving rod (24).

Description

Method for preparing thiodipropionic acid by using series dynamic kettle type reactor Technical Field The invention relates to the technical field of preparation of thiodipropionic acid, in particular to a method for preparing thiodipropionic acid by utilizing a series dynamic kettle reactor. Background 3,3' -Thiodipropionic acid is commonly called as thiodipropionic acid and also called as thiodipropionic acid, is an intermediate for synthesizing a thioester antioxidant, and the current domestic process for preparing the thiodipropionic acid mainly comprises an acrylic acid process and an acrylonitrile process. The acrylic acid process has low material cost, simple process and high yield and is widely used. The acrylic acid technology is that acrylic acid and sodium sulfide are subjected to Michael addition reaction under alkaline conditions to obtain sodium thiodipropionate, and then the sodium thiodipropionate is subjected to acidification, crystallization, spin-drying, leaching and drying chemical unit operation to obtain a pure thiodipropionate, wherein the reaction equation is shown in figure 4: According to different reaction modes, the batch reaction mode is divided into batch reaction and continuous reaction, the batch reaction mode is reported and adopted at present, and has the advantages of simple equipment, flexible operation, high conversion rate and the like, but the batch reaction mode also has the defects of more required matched equipment, high energy consumption, frequent start and stop, large workload, frequent contact of personnel with materials and the like, adverse safety, small management and productivity and the like Disclosure of Invention The invention aims to provide a method for preparing thiodipropionic acid by using a series dynamic kettle type reactor, so as to reduce the consumption of acrylic acid, reduce the content of polyacrylic acid and improve the yield and quality of finished products. In order to achieve the above purpose, the present invention adopts the following technical scheme: A method for preparing thiodipropionic acid by using a series dynamic kettle reactor, comprising the following steps: s1, preparing a reaction solution, namely preparing sodium sulfide and sodium hydroxide into aqueous solutions respectively, and adjusting the content of the aqueous solution of the sodium sulfide to 27-29% and the concentration of the sodium hydroxide solution to 25-30% according to experimental requirements; S2, feeding, namely respectively feeding 27-29% sodium sulfide aqueous solution, sodium hydroxide aqueous solution and acrylic acid into a reactor, adjusting the proportion of two-phase raw materials, controlling the molar ratio of sodium sulfide to acrylic acid to be 1:2.03, feeding the mixture into a reaction zone of a first dynamic kettle reactor at normal temperature through a pump, controlling the feeding speed of the materials, feeding the sodium hydroxide aqueous solution as another phase material into the first dynamic kettle reactor at normal temperature through the pump to adjust the pH value, feeding sulfuric acid solution as another phase material into a second dynamic kettle reactor at normal temperature through the pump, controlling the feeding speed of the two-phase material, controlling the molar ratio of the two-phase material to the material of the first dynamic kettle reactor to be 1:1, detecting the temperature and the pH value at any time on line or off line, and adjusting the feeding amount of the sulfuric acid solution according to the pH value; S3, heat exchange, namely controlling the temperature by using a temperature controller in the reaction process, so that the reaction temperature in the first step is kept between 70 ℃ and 80 ℃; S4, stopping, namely after the two-phase materials are mixed, the stopping time of the reaction solution is 60-600S, and the reaction is mixed under normal pressure; S5, discharging, namely discharging the material out of the first dynamic kettle type reactor after the reaction is stopped for a certain time, and entering the second dynamic kettle type reactor, and further performing an acidification reaction to obtain the thiodipropionic acid feed liquid. Preferably, the reactor in S2 includes a first dynamic tank reactor and a second dynamic tank reactor, the first dynamic tank reactor and the second dynamic tank reactor are both provided with built-in coils, the built-in coils keep the constant temperature systems of the first dynamic tank reactor and the second dynamic tank reactor through a heat exchange mechanism, the bottoms of the first dynamic tank reactor and the second dynamic tank reactor are respectively provided with a first reaction area and a second reaction area, motors are arranged on the first dynamic tank reactor and the second dynamic tank reactor, the motors are fixedly connected with the shaft rods, the lower ends of the shaft rods extend into the first reaction area and the second reaction