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CN-121990919-A - Method for synthesizing dimethyl carbonate by in-situ self-activation homogeneous catalysis transesterification

CN121990919ACN 121990919 ACN121990919 ACN 121990919ACN-121990919-A

Abstract

The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing dimethyl carbonate by in-situ self-activated homogeneous catalysis transesterification, which comprises the steps of taking organic sulfonate as a homogeneous catalyst, uniformly mixing with cyclic carbonate and methanol, stirring and refluxing for reaction for 1-8 hours at 55-80 ℃, cooling to room temperature, carrying out normal pressure distillation on reaction materials, and collecting fractions at 64-91 ℃ to obtain a mixture composed of methanol and dimethyl carbonate. The organic sulfonate catalyst can keep high catalytic activity and excellent solubility in multiple recycling, has the characteristics of self-activation and super water resistance, and can solve various problems of sodium alkoxide catalysts.

Inventors

  • ZENG JIE
  • YANG JIANGUO
  • ZHANG HONGBO
  • LIU MINGKAI

Assignees

  • 安徽工业大学

Dates

Publication Date
20260508
Application Date
20260408

Claims (8)

  1. 1. The method for synthesizing the dimethyl carbonate by in-situ self-activating homogeneous catalysis transesterification is characterized by comprising the following steps of: S1, taking organic sulfonate as a homogeneous catalyst, uniformly mixing the organic sulfonate with cyclic carbonate and methanol, stirring and refluxing the mixture at 55-80 ℃ for reaction for 1-8 hours, and cooling the mixture to room temperature; s2, carrying out normal pressure distillation on the material obtained in the step S1, and collecting mixed fractions consisting of methanol and target product dimethyl carbonate within the range of 64-91 ℃.
  2. 2. The method for synthesizing dimethyl carbonate by in-situ self-excited homogeneous catalysis transesterification according to claim 1, wherein in the step S1, the organic sulfonate is an organic sulfonate metal salt with good solubility in a mixture of cyclic carbonate and methanol, and the structural formula is Wherein R is H or alkyl, m is a natural number of 0-2, n is a positive integer of 1-3 and satisfies the relation of m+n=3, x is a positive integer of 2-4, and Me x+ is +2 to +4 valence metal ions with empty orbitals.
  3. 3. The method for synthesizing dimethyl carbonate by in-situ self-activated homogeneous catalysis transesterification according to claim 2, wherein Me x+ is any one of Mn 2+ 、Fe 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ ,Sc 3+ 、Cr 3+ 、Mn 3+ 、Co 3+ 、Fe 3+ 、Ti 4+ in the structural formula.
  4. 4. The method for synthesizing dimethyl carbonate by in-situ self-activated homogeneous catalysis transesterification according to claim 1, wherein in the step S1, the organic sulfonate is zinc salt of organic sulfonate.
  5. 5. The method for synthesizing dimethyl carbonate by in-situ self-activated homogeneous catalysis transesterification according to claim 1, wherein in the step S1, the organic sulfonate is metal triflate.
  6. 6. The method for synthesizing dimethyl carbonate by in-situ self-activated homogeneous catalysis transesterification according to claim 1, wherein in the step S1, the zinc salt of organic sulfonic acid is zinc triflate.
  7. 7. The method for synthesizing dimethyl carbonate by in-situ self-activated homogeneous catalysis transesterification according to claim 1, wherein in the step S1, the cyclic carbonate is any one or a mixture of two of ethylene carbonate and propylene carbonate.
  8. 8. The method for synthesizing dimethyl carbonate by in-situ self-excited homogeneous catalysis transesterification according to claim 1, wherein in the step S1, the mass ratio of the methanol to the cyclic carbonate is 3-15:1, and the amount of the organic sulfonate catalyst is 0.5-12% of the total mass of the cyclic carbonate and the methanol.

Description

Method for synthesizing dimethyl carbonate by in-situ self-activation homogeneous catalysis transesterification Technical Field The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing dimethyl carbonate by in-situ self-activation homogeneous catalysis transesterification. Background Dimethyl carbonate (DMC) can be used as raw material for organic synthesis reaction, environment-friendly solvent and has wide application. Compared with other synthetic routes, the method for synthesizing DMC by utilizing cyclic carbonate such as Propylene Carbonate (PC) or Ethylene Carbonate (EC) and methanol (MeOH) through transesterification has the advantages of mild condition, low equipment investment cost, high economy, high safety and the like, and is the main flow process for industrially synthesizing DMC at present. The reaction rate of direct transesterification of cyclic carbonate and MeOH is slow, the reaction has application value only by accelerating the catalyst, and the catalyst accelerates the reaction rate by changing the reaction path and reducing the energy-reducing barrier. During long-term operation or cyclic reaction, most catalysts for chemical reactions are inevitably affected by factors such as reaction materials, impurities, heat, oxygen and the like, and activity decay and physical properties (such as solubility) change irreversibly. The transesterification homogeneous catalyst in the prior art is characterized in that the catalytic activity is reduced along with the increase of the recycling times, the solubility of the transesterification homogeneous catalyst in reaction materials is also poor, and the phenomenon that the catalytic activity is automatically improved in the use process is extremely difficult to observe. In the commercial production of DMC by transesterification of cyclic carbonates with methanol, sodium methoxide is generally used as homogeneous catalyst. Sodium methoxide has higher catalytic activity on transesterification reaction, but has the main problems of lower solubility in a reaction mixture, easy crystallization and precipitation, and easy reaction of sodium methoxide with water and organic carbonate in raw materials to generate sodium carbonate solid with poorer solubility in a system in practical application. The problems are very easy to cause blockage of pipelines and towers, frequent maintenance of equipment and periodic replacement of catalysis, so that the catalysis efficiency is reduced, and the raw material waste and the production efficiency are reduced. Therefore, the development of a novel homogeneous catalysis DMC synthesis process has important industrial application value. In view of the above drawbacks, the present inventors have finally achieved the present invention through long-time studies and practices. Disclosure of Invention The invention aims to solve the problems of poor compatibility, water resistance, poor cycling stability and the like of the existing sodium alkoxide catalyst, and provides a method for synthesizing dimethyl carbonate by in-situ self-activated homogeneous catalysis transesterification. In order to achieve the above purpose, the invention discloses a method for synthesizing dimethyl carbonate by in-situ self-activated homogeneous catalysis transesterification, which comprises the following steps: S1, taking organic sulfonate as a homogeneous catalyst, uniformly mixing the organic sulfonate with cyclic carbonate and methanol, stirring and refluxing the mixture at 55-80 ℃ for reaction for 1-8 hours, and cooling the mixture to room temperature; s2, carrying out normal pressure distillation on the material obtained in the step S1, and collecting mixed fractions consisting of methanol and target product dimethyl carbonate within the range of 64-91 ℃. In the step S1, the organic sulfonate is organic sulfonate metal salt with good solubility in the mixture of cyclic carbonate and methanol, and the structural formula is as followsWherein R is H or alkyl, m is a natural number of 0-2, n is a positive integer of 1-3 and satisfies the relation of m+n=3, x is a positive integer of 2-4, and Me x+ is +2 to +4 valence metal ions with empty orbitals. In the structural formula, me x+ is any one of Mn2+、Fe2+、Ni2+、Cu2+、Zn2+,Sc3+、Cr3+、Mn3+、Co3+、Fe3+、Ti4+. In the step S1, the organic sulfonate is zinc salt of organic sulfonate. In the step S1, the organic sulfonate is a metal triflate. In the step S1, the organic sulfonate is zinc triflate. In the step S1, the cyclic carbonate is any one or a mixture of two of ethylene carbonate and propylene carbonate. In the step S1, the mass part ratio of the substances of the methanol and the cyclic carbonate is 3-15:1, and the dosage of the organic sulfonate catalyst is 0.5-12% of the total mass of the cyclic carbonate and the methanol. Organic sulfonic acid belongs to strong acid, salt formed by acid radical ion and metal ion belongs to ionic compound, and th