Search

CN-122010894-A - Catalytic synthesis method of propylene carbonate

CN122010894ACN 122010894 ACN122010894 ACN 122010894ACN-122010894-A

Abstract

The invention discloses a catalytic synthesis method of propylene carbonate, which belongs to the technical field of propylene carbonate synthesis and is used for solving the technical problems that the conversion rate, the selectivity and the cyclic regeneration stability of a catalyst are required to be further improved in the prior art for preparing propylene carbonate by catalyzing the reaction of 1, 2-propylene glycol and carbon dioxide. According to the invention, epoxy silane-ionic salt is introduced after pretreatment of the active carbon carrier, and then the high-dispersion immobilized Lewis acid center is introduced by using the ethyl orthosilicate sol-gel, so that not only is the conversion rate and selectivity of the catalytic preparation of propylene carbonate effectively improved, but also the performance stability of the cyclized catalyst in recycling is improved.

Inventors

  • SU QIANGDE
  • LI RUICHEN
  • SUN CHENGJIAO
  • CAO GUODONG

Assignees

  • 山东利兴新材料科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260202

Claims (10)

  1. 1. A catalytic synthesis method of propylene carbonate, which is characterized by comprising the following steps: Adding 1, 2-propylene glycol and a cyclization catalyst into a high-pressure reaction kettle, stirring, introducing inert gas into the high-pressure reaction kettle, displacing and removing air in the high-pressure reaction kettle, heating the high-pressure reaction kettle to 115-125 ℃, introducing carbon dioxide into the high-pressure reaction kettle, regulating the pressure of the high-pressure reaction kettle to 4-5MPa, carrying out heat preservation reaction for 6-8h, cooling the high-pressure reaction kettle to room temperature, carrying out suction filtration, and obtaining propylene carbonate reaction liquid and recycling the cyclization catalyst.
  2. 2. The catalytic synthesis method of propylene carbonate according to claim 1, wherein the ethyl orthosilicate and purified water are mixed and stirred, the temperature of a reaction system is raised to 70-80 ℃, hydrochloric acid is added into the reaction system, the pH value of the system is regulated to be 3.5-4.5, the reaction is kept for 50-70min, oxalic acid is added into the reaction system, the reaction is carried out for 50-60min, the temperature of the reaction system is reduced to 50-55 ℃, zinc acetate and tetrabutyl titanate are added into the reaction system, stirring is carried out for 45-55min, ionic salt modified activated carbon is added into the reaction system, the temperature is kept and stirred for 16-18h, and the cyclizing catalyst is obtained after the post treatment.
  3. 3. The catalytic synthesis method of propylene carbonate according to claim 2, wherein the dosage ratio of ethyl orthosilicate, purified water, oxalic acid, zinc acetate, tetrabutyl titanate and ionic salt modified activated carbon is 5g:50mL:0.2-0.3g:0.4-0.5g:1.1-1.5g:20g.
  4. 4. The catalytic synthesis method of propylene carbonate according to claim 2, wherein the ionic salt modified activated carbon is obtained by processing the following steps: a1, mixing and stirring epoxy modified activated carbon, ethyl acetate and 1, 4-diazabicyclo [2.2.2] octane-2-acetamide, heating a reaction system to 60-70 ℃, carrying out heat preservation reaction for 60-80min, cooling the reaction system to 50-55 ℃, adding 1, 3-propane sultone into the reaction system, carrying out heat preservation and stirring for 20-22h, and carrying out aftertreatment to obtain an ionic salt modified activated carbon precursor; A2, mixing and stirring the ion salt modified activated carbon precursor and sulfuric acid for 20-30min, heating the reaction system to 75-85 ℃, carrying out heat preservation reaction for 8-10h, and carrying out aftertreatment to obtain the ion salt modified activated carbon.
  5. 5. The catalytic synthesis method of propylene carbonate according to claim 4, wherein in the step A1, the dosage ratio of the epoxy modified activated carbon, ethyl acetate, 1, 4-diazabicyclo [2.2.2] octane-2-acetamide and 1, 3-propane sultone is 5g:30mL:0.8g:1.3g, and in the step A2, the solid-to-liquid ratio of the ionic salt modified activated carbon precursor and sulfuric acid is 1:10, and the concentration of sulfuric acid is 2-3mol/L.
  6. 6. The catalytic synthesis method of propylene carbonate according to claim 4, wherein the preparation method of the epoxy modified activated carbon comprises the steps of mixing and stirring the pretreated activated carbon, the absolute ethyl alcohol and the KH-560, heating a reaction system to 50-60 ℃, adding a base catalyst into the reaction system, carrying out heat preservation reaction for 50-70min, and carrying out aftertreatment to obtain the epoxy modified activated carbon.
  7. 7. The catalytic synthesis method of propylene carbonate according to claim 6, wherein the dosage ratio of the pretreated activated carbon, absolute ethyl alcohol, KH-560 and base catalyst is 5g:50mL:0.9-1.1g:8mL, and the base catalyst is 2-3mol/L sodium hydroxide solution.
  8. 8. The catalytic synthesis process of propylene carbonate according to claim 6, wherein the pretreated activated carbon is processed by the steps of: b1, mixing active carbon with hydrochloric acid solution, heating a reaction system to 50-60 ℃, preserving heat, soaking for 120-150min, and performing aftertreatment to obtain acid-treated active carbon; b2, mixing the acid-treated activated carbon with an alkali solution, heating a reaction system to 40-50 ℃, preserving heat, soaking for 10-12 hours, and performing aftertreatment to obtain pretreated activated carbon; And B3, spreading the pretreated activated carbon in a tube furnace, heating the tube furnace to 750-800 ℃ under the protection of inert gas atmosphere, and carrying out heat preservation and roasting for 2-3 hours, and carrying out post-treatment to obtain the pretreated activated carbon.
  9. 9. The catalytic synthesis method of propylene carbonate according to claim 8, wherein in the step B1, the solid-to-liquid ratio of the activated carbon to the hydrochloric acid solution is 1:5-6, the hydrochloric acid solution is composed of 1-2mol/L hydrochloric acid and sodium dodecyl sulfate according to 100ml:2-3g, in the step B2, the solid-to-liquid ratio of the acid treated activated carbon to the alkali solution is 1:5-6, the alkali solution is 2-3mol/L potassium hydroxide solution, and in the step B3, the heating rate of the tube furnace is 3-5 ℃.
  10. 10. The catalytic synthesis method of propylene carbonate according to claim 1, wherein the weight ratio of the 1, 2-propanediol and the cyclization catalyst is 50:3-5.

Description

Catalytic synthesis method of propylene carbonate Technical Field The invention relates to the technical field of propylene carbonate synthesis, in particular to a catalytic synthesis method of propylene carbonate. Background Propylene carbonate (PC for short) is an organic carbonate compound with high dielectric constant, low volatility and good chemical stability, is often used as an important solvent of lithium ion battery electrolyte, a high boiling point solvent in polymer synthesis, an intermediate of fine chemicals such as medicines and pesticides, and the like, can be used as an environment-friendly solvent in paint, ink and cleaning agents, and is synthesized by taking carbon dioxide and 1, 2-propanediol as raw materials, so that the utilization of CO 2 can be realized, high-risk raw materials such as phosgene and the like are avoided, the organic carbonate compound has green and sustainable development direction, and because CO 2 molecules have high thermodynamic stability and strong chemical inertia, and the-OH bond energy in 1, 2-propanediol molecules is larger, the high-efficiency condensation and cyclization are difficult to occur spontaneously under mild conditions, and the reaction needs to depend on a high-efficiency catalytic system to reduce the reaction activation energy and inhibit side reactions. At present, a catalytic system for catalyzing 1, 2-propylene glycol and CO 2 to synthesize propylene carbonate comprises a homogeneous quaternary ammonium salt, quaternary phosphonium salt, organic base or ionic liquid system, heterogeneous metal oxide, metal salt supported catalyst, heteropolyacid and salt supported catalyst thereof and the like, and the homogeneous catalytic system generally has the advantages of higher initial activity, easily-adjusted formula and the like, but in industrial application, the homogeneous catalyst and a product are in the same liquid phase, are difficult to separate and recycle after the reaction is finished, and part of organic catalyst or ionic liquid has the problems of insufficient thermal stability and easy decomposition or deactivation under the high-temperature high-pressure CO 2 environment and is difficult to realize multiple recycling. The heterogeneous solid catalyst has obvious advantages in the aspects of recycling and process amplification, but the traditional heterogeneous solid catalyst has low specific surface area or unreasonable pore channel structure, so that the accessibility of effective active sites is insufficient, the external mass transfer and the internal mass transfer are limited, and therefore, the higher conversion rate and the high selectivity are difficult to be considered, in addition, a plurality of supported metal catalysts are easy to cause metal species migration, agglomeration or leaching under the conditions of high temperature, high pressure CO 2 and water/alcohol, the problems of pore channel blockage, structural collapse and the like in the regeneration process are outstanding, and the activity and the selectivity attenuation in the catalyst recycling process are obvious. In view of the technical drawbacks of this aspect, a solution is now proposed. Disclosure of Invention The invention aims to provide a catalytic synthesis method of propylene carbonate, which is used for solving the technical problems that the conversion rate and selectivity of the propylene carbonate prepared by catalyzing the reaction of 1, 2-propylene glycol and carbon dioxide and the stability of the catalyst in the prior art are required to be further improved. The invention aims at realizing the technical scheme that the catalytic synthesis method of propylene carbonate comprises the following steps: Adding 1, 2-propylene glycol and a cyclization catalyst into a high-pressure reaction kettle, stirring, introducing inert gas into the high-pressure reaction kettle, displacing and removing air in the high-pressure reaction kettle, heating the high-pressure reaction kettle to 115-125 ℃, introducing carbon dioxide into the high-pressure reaction kettle, regulating the pressure of the high-pressure reaction kettle to 4-5MPa, carrying out heat preservation reaction for 6-8h, cooling the high-pressure reaction kettle to room temperature, carrying out suction filtration, and obtaining propylene carbonate reaction liquid and recycling the cyclization catalyst. Further, mixing and stirring tetraethoxysilane and purified water, heating a reaction system to 70-80 ℃, adding hydrochloric acid into the reaction system, adjusting the pH value of the system to be 3.5-4.5, carrying out heat preservation reaction for 50-70min, adding oxalic acid into the reaction system, carrying out reaction for 50-60min, cooling the reaction system to 50-55 ℃, adding zinc acetate and tetrabutyl titanate into the reaction system, stirring for 45-55min, adding ionic salt modified activated carbon into the reaction system, carrying out heat preservation stirring for 16-18h, and car