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CN-117658962-B - Technological method for preparing succinic anhydride by maleic anhydride hydrogenation

CN117658962BCN 117658962 BCN117658962 BCN 117658962BCN-117658962-B

Abstract

A process for preparing succinic anhydride by hydrogenating maleic anhydride uses organic solvent which has boiling point not higher than 150 deg.C and can dissolve maleic anhydride and does not react with maleic anhydride as reaction solvent, after maleic anhydride is dissolved, the organic solvent reacts with hydrogen and solid catalyst in hydrogenation reactor, reaction pressure is regulated to make reaction temp. be 30-150 deg.C, solvent in reaction system can be kept in boiling state by regulating pressure, gas outlet is set on hydrogenation reactor, organic solvent and unreacted hydrogen are continuously discharged from gas outlet, after reaction is completed, the reaction product can be undergone the processes of solid-liquid separation and/or crystallization separation so as to obtain succinic anhydride. The invention takes the organic solution for dissolving maleic anhydride as the raw material, and the solution in the reaction system is kept in a boiling state by utilizing the adjustment of pressure, so that the heat of the reaction system can be timely taken out by utilizing the phase change of the organic solvent, the problem of temperature rise of the technology for preparing succinic anhydride by hydrogenating maleic anhydride is solved, and the method is simple and easy to operate and is convenient for industrial popularization and application.

Inventors

  • JIANG RUI
  • YANG CHUNYAN
  • MA HUIXIA
  • ZHAO CHENGHAO
  • LI LANPENG

Assignees

  • 中国石油化工股份有限公司
  • 中石化（大连）石油化工研究院有限公司

Dates

Publication Date
20260505
Application Date
20220830

Claims (14)

  1. 1. A process for preparing succinic anhydride by hydrogenating maleic anhydride includes such steps as dissolving maleic anhydride in tetrahydrofuran or methyl formate as solvent, reacting with hydrogen and solid catalyst in hydrogenation reactor, regulating reaction pressure to 80-90 deg.C, boiling solvent in reaction system, setting gas outlet on hydrogenation reactor, continuously exhausting organic solvent and unreacted hydrogen from gas outlet, and solid-liquid separation and/or crystallizing separation.
  2. 2. The process according to claim 1, wherein a stirring device is arranged in the hydrogenation reaction device.
  3. 3. The process of claim 1 wherein the solid catalyst is fixed to a location outside the bottom of the hydrogenation reactor.
  4. 4. The process of claim 2 wherein the solid catalyst is fixed to a stirring device.
  5. 5. The process of claim 4 wherein the solid catalyst is encapsulated in a plurality of porous gauze bags and is dispersedly affixed to the paddles.
  6. 6. The process of claim 1, wherein the active component of the solid catalyst is at least one selected from Pd, pt, ru, ni and Cu, and the support is an acid resistant support.
  7. 7. The process according to claim 1, wherein the concentration of maleic anhydride is 20% to 70% by weight.
  8. 8. The process of claim 7, wherein the concentration of maleic anhydride is 25 wt.% to 60 wt.%.
  9. 9. The process of claim 8, wherein the concentration of maleic anhydride is from 30wt% to 50wt%.
  10. 10. The process according to claim 1, wherein the hydrogenation reaction is carried out for a period of 20min to 5h.
  11. 11. The process according to claim 1, wherein the hydrogen is introduced in a molar ratio of hydrogen to maleic anhydride of 0.1 to 1000:1.
  12. 12. The process of claim 7, wherein hydrogen is introduced from the bottom of the hydrogenation reactor or from a conduit into a net bag containing catalyst.
  13. 13. The process of claim 1, further comprising the step of recycling the mother liquor after crystallization separation to the maleic anhydride hydrolysis unit.
  14. 14. The process of claim 1 further comprising the step of condensing the water vapor at the gas outlet and unreacted hydrogen to recover hydrogen.

Description

Technological method for preparing succinic anhydride by maleic anhydride hydrogenation Technical Field The invention relates to a process method for preparing succinic anhydride by maleic anhydride hydrogenation, belonging to the technical field of catalytic processes. Background As the problem of plastic contamination increases, the demand for PBS (polybutylene succinate) series copolyesters has increased due to their excellent properties of degradable materials. However, although the polymerization technology of PBS series copolyester degradable plastic products is mature, the synthesis technology of large-scale low-cost succinic acid monomer materials is not complete, and the popularization and application of high-quality degradable materials are restricted. At present, a succinic acid and butanediol polymerization method is adopted to produce PBS materials, and water is required to be removed in the polymerization reaction, so that the molecular weight of the materials and the properties of synthetic materials are influenced. And succinic anhydride is directly polymerized with butanediol, and the product quality is higher than that of an acid-alcohol polymerization material because the polymerization process is compared with succinic acid, and the succinic anhydride product has a higher development prospect. However, the reaction for generating succinic anhydride by maleic anhydride catalytic hydrogenation is double bond saturation reaction, so that the reaction is easy to carry out, and meanwhile, the reaction is highly exothermic (delta H= -128 KJ/mol), so that the temperature rise of the maleic anhydride hydrogenation reaction is large. In addition, various unsaturated bonds such as C=C and C=O exist in the direct hydrogenation reaction of maleic anhydride, the reaction temperature sensitivity is high, and if the temperature is increased in the hydrogenation reaction of maleic anhydride, the saturation of C=O double bonds is very easy to occur, and by-products such as butyrolactone and the like are generated, so that the reaction effect is influenced. Because of the intense heat generated by the hydrogenation of maleic anhydride, different methods have been used by current researchers to solve this problem, and thus the smooth progress of the reaction has been achieved. In the patent CN103570650a, a mixed solution of an organic solvent and maleic anhydride is used as a raw material, heterogeneous catalysts such as silicon-aluminum are used, a two-stage reactor reaction method is used, the first-stage reactor is used for pre-hydrogenation, the reaction heat generation is reduced, and the two-stage reactor is used for realizing the conversion of high selectivity and high conversion rate of maleic anhydride hydrogenation. Rectifying and separating the generated reaction product, recycling the solvent, and hydrolyzing and crystallizing the separated succinic anhydride to generate succinic acid. Patent CN102311332a discloses a method for producing succinic acid, which uses butyrolactone as solvent, uses heterogeneous catalyst of alumina and other carrier, prepares maleic anhydride/gamma-butyrolactone solution, uses latent heat of gamma-butyrolactone solution to implement temperature control, and further implements smooth reaction. And separating and hydrolyzing the generated succinic anhydride, and crystallizing to obtain the high-purity succinic acid. Although the above research method realizes high selectivity conversion of maleic anhydride, it can be seen that in order to reduce the influence caused by reaction heat, researchers usually adopt a large amount of solvent to dilute maleic anhydride, reduce the total heat release amount of reaction in the same reaction volume in the reaction system, realize temperature rise reduction by using latent heat, the concentration of maleic anhydride which can be treated is low, and the sections of solvent circulation, product separation and the like are increased, thus increasing the investment of reaction devices and the cost of material consumption and energy consumption. Disclosure of Invention In the research aiming at the technical problems, the inventor thinks that if the solvent is subjected to phase change by controlling the reaction conditions, the phase change enthalpy of the solvent is far higher than the enthalpy change of the temperature rise of the solvent, and the solvent after the phase change is taken out in time, so that the temperature rise of the high exothermic reaction can be effectively controlled as a heating mode, the accurate control of the reaction temperature is realized, the concentration range of the maleic anhydride which can be processed in the prior art can be widened, and the direct hydrogenation of the maleic anhydride solution to prepare the succinic anhydride is realized on the basis of ensuring the reaction conversion rate and the selectivity. In order to achieve the technical purpose, the invention adopts the following techn