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CN-122006804-A - Preparation method of triethylamine-based ionic liquid functionalized Salen material and application of triethylamine-based ionic liquid functionalized Salen material in CO2Application in cycloaddition conversion

CN122006804ACN 122006804 ACN122006804 ACN 122006804ACN-122006804-A

Abstract

The invention provides a preparation method of a triethylamine-based ionic liquid functionalized Salen material and application of the triethylamine-based ionic liquid functionalized Salen material in CO 2 cycloaddition conversion, and belongs to the technical field of ionic liquid catalytic material synthesis. The salicylaldehyde derivative containing triethylamine ion liquid and the MCM-41 molecular sieve modified by 3-aminopropyl triethoxysilane (APTES) are used for constructing a Salen structure through an aldol condensation reaction, and the Salen structure has active sites of triethylamine cations and halogen anions and is used for synthesizing Propylene Carbonate (PC) through CO-catalysis of CO 2 . The catalytic material has the advantages of multiple active sites, uniform distribution, good stability, simple synthesis process, low synthesis cost, green and environment-friendly synthesis process and the like. The prepared MCM-Salen-TEA catalytic material is applied to CO 2 to synthesize PC, and has excellent catalytic performance under milder reaction conditions.

Inventors

  • LI LING
  • FU XIAOYUN
  • ZHANG MENGJIA
  • LIN JIANGHUI
  • CAI GUOHUI
  • HUANG CHENGMEI
  • LIU BINGYAN
  • Zheng Ruixuan

Assignees

  • 福州大学

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. A preparation method of a triethylamine-based ionic liquid functionalized Salen material is characterized in that a catalyst is prepared by loading triethylamine-based ionic liquid on the surface of an MCM-41 molecular sieve material through a Salen structure.
  2. 2. The method according to claim 1, comprising the steps of: (1) The synthesis of halogenated compound, which is to mix aldehyde group-containing compound, paraformaldehyde and hydrobromic acid, fully stir and react, and then extract and wash the mixture to obtain halogenated compound containing halogen anions; (2) Dissolving halogenated compound in organic solvent to prepare solution A, adding triethylamine compound, stirring thoroughly to react, filtering, washing and drying to obtain triethylamine ionic liquid; (3) Modification of MCM-41 molecular sieve, namely drying the molecular sieve, adding the molecular sieve into an organic solvent, mixing with a silane coupling agent, heating, stirring, reacting, centrifuging, washing and drying to obtain MCM-NH 2 material; (4) The method comprises the steps of dissolving triethylamine-Salen-TEA in an organic solvent to prepare a solution B, dispersing MCM-NH 2 in the organic solvent, adding the solution B, heating, stirring, reacting, centrifuging, washing and drying to obtain the triethylamine-Salen ionic liquid functionalized Salen material MCM-Salen-TEA.
  3. 3. The method according to claim 2, wherein the aldehyde group-containing compound in the step (1) is 3-t-butylsalicylaldehyde.
  4. 4. The method according to claim 2, wherein the reaction temperature in the step (1) is 50-80 ℃, the stirring time is 15-24 hours, and the molar ratio of the aldehyde group-containing compound, hydrogen bromide and paraformaldehyde is 1.0:5.0-8.0:1.2-1.5.
  5. 5. The method according to claim 2, wherein the organic solvent in the step (2) is toluene, the reaction temperature is 110-120 ℃, the stirring time is 2-8 hours, and the molar ratio of triethylamine to halogenated compound is 1.0-2.0:2.0-3.0.
  6. 6. The method of claim 2, wherein in the step (3), the drying temperature of the molecular sieve is 100-150 ℃, the time is 4-8 hours, the silane coupling agent is 3-aminopropyl triethoxysilane, the organic solvent is toluene, the reaction temperature is 100-120 ℃, the stirring time is 18-28 hours, and the mass ratio of the silane coupling agent to the molecular sieve is 1.0:1.5-3.0.
  7. 7. The method of claim 2, wherein the organic solvent in the step (4) is ethanol, the reaction temperature is 60-80 ℃, the stirring time is 36-50h, and the mass ratio of MCM-NH 2 to triethylamine-based ionic liquid is 1.0:2.0-4.0.
  8. 8. Triethylamino ionic liquid functionalized Salen material MCM-Salen-TEA prepared according to any one of claims 1-7.
  9. 9. The use of a triethylamine-based ionic liquid functionalized Salen material MCM-Salen-TEA as defined in claim 8 as a catalyst in a cycloaddition reaction of carbon dioxide with propylene oxide to propylene carbonate.
  10. 10. The process according to claim 9, wherein the reaction conditions for the production of propylene carbonate are CO 2 0.5.5-2.5 MPa, the reaction temperature is 80-160 ℃ and the reaction time is 3-8h.

Description

Preparation method of triethylamine-based ionic liquid functionalized Salen material and application of triethylamine-based ionic liquid functionalized Salen material in CO 2 cycloaddition conversion Technical Field The invention belongs to the technical field of ionic liquid catalytic material synthesis, and particularly relates to a preparation method of a triethylamine-based ionic liquid functionalized Salen material and application of the triethylamine-based ionic liquid functionalized Salen material in CO 2 cycloaddition conversion. Background The excessive emission of CO 2 in today's society causes numerous environmental problems, but CO 2 can also be converted into high value-added chemicals as a rich, inexpensive and non-toxic carbon source. The conversion of CO 2 is mainly the conversion of hydrogen to methanol, hydrocarbons or reforming with methane to synthesis gas, alcohols or epoxides to carbonates, etc. Wherein the utilization rate of the reaction atoms for preparing propylene carbonate by the CO 2 cycloaddition reaction reaches 100 percent. Meets the requirements of the current green chemical technology, and the propylene carbonate product is widely applied in industry. Therefore, the research is of great significance. The main production process of propylene carbonate includes phosgene process, urea process, ester exchange process and epoxy propane and CO 2 synthesizing process. In the phosgene method, because phosgene has strong toxicity and hydrochloric acid is generated as a byproduct during the reaction, the method is basically eliminated at present, and the transesterification method generally needs alkali metal or alkaline earth metal as a catalyst, and the catalyst has great harm to human bodies and is not a green chemical process. The homogeneous catalytic system of the reaction of the urea method is dissolved in reactants and is difficult to recycle. The synthesis method of propylene oxide and CO 2 is an addition reaction, the atomic utilization rate of the propylene oxide can reach 100% theoretically, byproducts are hardly generated in the process, the equipment is free from corrosion, the national green development requirements are met, and the future development prospect is large. The catalytic mechanism of the cycloaddition reaction of CO 2 mainly comprises three steps of epoxide ring opening, CO 2 activation and insertion and internal cyclization reaction. Firstly, a C-O bond in epoxide is easy to form a hydrogen bond, the epoxide is polarized by the hydrogen bond and then is broken, and the ring opening step of the epoxide is completed after the C-O bond is broken; CO 2 is generally activated by Lewis acid or Lewis base active site, after CO 2 is activated, the spatial structure of the molecule becomes curved, meanwhile, C=O bond starts to break and is inserted into epoxide after ring opening to form non-closed-loop carbonate, finally, under the action of static electricity, the catalyst is reduced and removed from the reaction system, so that donor ions for ring opening of epoxide can be separated, and then the molecule starts to close to form the product cyclic carbonate. The existing catalyst for the cycloaddition reaction of CO 2 mainly comprises metalloporphyrin, an ionic liquid complex, a metal Salen complex and the like, the metalloporphyrin synthesis process is complex, the ionic liquid and the metal Salen complex belong to homogeneous catalysis, and the catalyst is difficult to recycle. It is therefore necessary to develop a heterogeneous catalytic system with efficient catalytic properties. Disclosure of Invention The invention aims to provide a preparation method of a triethylamine-based ionic liquid functionalized Salen material, and the preparation method is applied to the synthesis of propylene carbonate by a catalytic epoxypropane-CO 2 cycloaddition method under a milder condition. In order to achieve the above object, the present invention adopts the following technical scheme: A triethylamine-based ionic liquid functionalized Salen material is prepared by synthesizing triethylamine-based ionic liquid Sal-TEA by utilizing a halogenated compound and triethylamine, carrying out surface modification on an MCM-41 molecular sieve by utilizing APTES, and grafting the ionic liquid onto the surface of the modified molecular sieve through aldol condensation to form a Salen ligand structure, thereby obtaining the MCM-Salen-TEA material. The invention further provides a preparation method of the catalyst, which comprises the following steps: S1, weighing an aldehyde group-containing compound, hydrobromic acid and paraformaldehyde, mixing, fully stirring at a proper temperature, and washing and extracting after the reaction is completed to obtain a halogen anion-containing halogenated compound 5-bromomethyl-3-tertiary butyl-salicylaldehyde. S2, dissolving halogenated compound in organic solvent to prepare solution A, adding triethylamine into the solution A, fully stirring