Search

CN-121669311-B - Heterogeneous catalyst and application thereof in preparation of alkyl carbonate by decarbonylation of alkyl oxalate

CN121669311BCN 121669311 BCN121669311 BCN 121669311BCN-121669311-B

Abstract

The invention provides a heterogeneous catalyst and application thereof in preparing alkyl carbonate by decarbonylation of alkyl oxalate, wherein the heterogeneous catalyst is transition metal modified organic amine grafted polystyrene resin obtained by grafting chloromethylated polystyrene resin with organic tertiary amine and then modifying with metal anion complex. The heterogeneous catalyst can fully utilize the important intermediate dimethyl oxalate in the process of preparing the ethylene glycol from the coal, and can realize the efficient conversion of the dimethyl oxalate into the dimethyl carbonate and the derivative alkyl ester thereof under mild conditions by decarbonylating the dimethyl oxalate.

Inventors

  • LUO LEI
  • WANG RUYANG
  • GONG XIAOYU
  • QIAN JUN
  • ZHANG BING
  • YUE LIYING
  • YU JUN
  • ZHENG XI
  • GAO JIN

Assignees

  • 东华工程科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260212

Claims (8)

  1. 1. The application of the heterogeneous catalyst in preparing alkyl carbonate by decarbonylating alkyl oxalate is characterized in that the heterogeneous catalyst is transition metal modified organic amine grafted polystyrene resin obtained by grafting chloromethylated polystyrene resin with organic tertiary amine and then modifying with transition metal anion complex; The transition metal anion complex is at least one of CuCl 4 2- 、CoCl 4 2- 、SnCl 4 2- 、ZnCl 4 2- or NiCl 4 2- anion complex.
  2. 2. The use of the heterogeneous catalyst according to claim 1 for decarbonylating alkyl oxalate to prepare alkyl carbonate, wherein the organic tertiary amine is at least one of trimethylamine, triethylamine, tributylamine, dodecyldimethyl tertiary amine, tetradecyldimethyl tertiary amine or polyethyleneimine.
  3. 3. Use of the heterogeneous catalyst according to claim 1 or 2 for the decarbonylation of alkyl oxalate to alkyl carbonate, characterized in that the mass ratio of chloromethylated polystyrene resin to organic tertiary amine is 20:1-2:1, and the mass ratio of chloromethylated polystyrene resin to transition metal anion complex is 50:1-5:1.
  4. 4. The application of the heterogeneous catalyst in preparing alkyl carbonate by decarbonylating alkyl oxalate according to claim 1 or 2, wherein the grafting comprises the steps of adding chloromethylated polystyrene resin into an organic solvent for full swelling, adding organic tertiary amine and inorganic base, and stirring for reaction to obtain organic amine grafted polystyrene resin; the organic solvent is at least one of N, N-dimethylformamide or N, N-dimethylacetamide, the inorganic base is at least one of potassium carbonate, sodium carbonate or potassium phosphate, and the stirring reaction temperature is 80-120 ℃ and the stirring reaction time is 8-12 h.
  5. 5. The application of the heterogeneous catalyst in the preparation of alkyl carbonate by decarbonylation of alkyl oxalate according to claim 4, wherein the modification comprises adding organic amine grafted polystyrene resin into an alcohol solvent for uniform dispersion, and then adding a transition metal anion complex for stirring reaction to obtain transition metal modified organic amine grafted polystyrene resin; the alcohol solvent is at least one of ethanol, methanol or isopropanol, and the stirring reaction temperature is 20-40 ℃ and the stirring reaction time is 1-3 h.
  6. 6. The use of the heterogeneous catalyst according to claim 1 for the decarbonylation of alkyl oxalate to produce alkyl carbonate, wherein the alkyl oxalate has the molecular structural formula shown below: the molecular structural formula of the alkyl carbonate is shown as follows: wherein R, R' are each independently an alkyl group having 1 to 8 carbon atoms.
  7. 7. The application of the heterogeneous catalyst in the preparation of alkyl carbonate by decarbonylation of alkyl oxalate according to claim 1 or 6, which is characterized in that the application specifically comprises the steps of introducing a raw material liquid of the alkyl oxalate into a fixed bed reactor filled with the heterogeneous catalyst, pressurizing and heating for decarbonylation reaction, and rectifying the obtained reaction liquid to obtain the alkyl carbonate.
  8. 8. The use of the heterogeneous catalyst according to claim 7 for the decarbonylation of alkyl oxalate to alkyl carbonate, wherein the decarbonylation reaction is carried out at a temperature of 100 to 180 ℃ and a pressure of 0.1 to 1.0 Mpa and a residence time of 0.5 to 5.0 h.

Description

Heterogeneous catalyst and application thereof in preparation of alkyl carbonate by decarbonylation of alkyl oxalate Technical Field The invention relates to the technical field of organic synthesis, in particular to a heterogeneous catalyst and application thereof in preparing alkyl carbonate by decarbonylation of alkyl oxalate. Background Alkyl carbonates, such as dimethyl carbonate (DMC, C 3H6O3), are a colorless, transparent, slightly pungent, low-toxicity liquid with a molecular weight of 90.07, a density of 1.069 g cm -, a melting point of 2-4 ℃, a boiling point of 90 ℃, a flash point of 17 ℃, are water-immiscible, and are optionally miscible with alcohols, ketones, esters, aromatic hydrocarbons. The molecule of the catalyst has carbonyl, methoxy and alkoxy, has various reaction performances such as methylation, carbonylation, transesterification and the like, is safe and environment-friendly in transportation, storage and use processes, is recognized as a new organic synthesis basic stone and a green chemical raw material, and can be used as a high-performance fuel additive. About 65% of DMC is used worldwide downstream for Polycarbonate (PC) synthesis, the remainder being used for high value-added products such as electrolyte solvents, developer solutions, pesticide/pharmaceutical intermediates, isocyanates, polycarbonate diols, long chain alkyl carbonates, etc. The apparent DMC consumption of China reaches 200 ten thousand tons/year in 2024, wherein the ratio of the new energy automobile electrolyte to the domestic PC field is about 70%, the new energy automobile electrolyte is still increased at the rate of annual average >15%, and the supply and demand gap is continuously enlarged. Since 1918 phosgene method (COCl 2+CH3 OH) appeared, DMC synthesis technology has undergone multi-generation route iteration such as phosgene method, methanol oxidative carbonylation method, transesterification method, urea alcoholysis method, CO 2/methanol direct synthesis method, etc., although methanol oxidative carbonylation method (liquid phase slurry, nitrous acid ester, direct gas phase) realizes industrialization, but has the fatal defects of quick catalyst deactivation, reactor corrosion, inflammability and explosiveness, NO x pollution, single pass conversion rate less than or equal to 20%, etc., only individual devices in China operate, and the expansion is limited. Transesterification (ethylene oxide/CO 2. Fwdarw. Ethylene carbonate+CH 3 OH)DMC+ethylene glycol) is mild in reaction and high in yield, but is long in steps, huge in equipment and high in investment, and DMC yield is limited by balance, so that production cost is high. The direct synthesis method of urea alcoholysis and CO 2/methanol has high atom economy, but has limited chemical balance and yield of less than 10%, and the generated water causes the catalyst to be hydrolyzed and deactivated, so the method still stays in a laboratory or a small test stage at present. The method for preparing DMC (DMO- & gtDMC+CO) by decarbonylation of dimethyl oxalate is a new reaction path which is in recent years, the sources of raw materials DMO are wide, the cost is low, the reaction is completed in one step, the atomic economy is more than 90%, the byproduct CO can be used as fuel gas or raw materials for oxo synthesis, no waste water or salt slag exists, and the method accords with the green chemical industry direction, however, the method has the following technical bottlenecks: (1) DMO is easy to pyrolyze at high temperature (> 240 ℃) to generate oxalic acid, CO 2 and methyl formate, so that the selectivity is reduced; (2) The traditional homogeneous base catalyst (K 2CO3、CH3 ONa) has high activity but difficult separation and easy hydrolysis and deactivation; (3) Conventional heterogeneous catalysts (activated carbon loaded with alkali metals) are prone to separation but face industrial barriers to active center loss and a lifetime of <100 h. Therefore, the development of a novel technology for preparing the dimethyl carbonate by decarbonylating the dimethyl oxalate, which can be operated under mild conditions with high efficiency and long period and is easy to amplify, and the matching of a low-energy separation scheme are urgent demands at present. The preparation of the dimethyl carbonate and the alkyl ester derived from the dimethyl carbonate is realized through decarbonylation of the dimethyl oxalate, and the method has very important practical significance for reducing the preparation cost of the alkyl ester carbonate and improving the comprehensive utilization of the intermediate product of the ethylene glycol prepared from coal. Disclosure of Invention Based on the technical problems existing in the background technology, the invention provides a heterogeneous catalyst and application thereof in preparing alkyl carbonate by decarbonylating alkyl oxalate, the heterogeneous catalyst can be used for fully utilizing an important intermediate, namely