Search

CN-121990918-A - Method for coproducing methyl ethyl carbonate and diethyl carbonate by homogeneous catalysis

CN121990918ACN 121990918 ACN121990918 ACN 121990918ACN-121990918-A

Abstract

The invention relates to the technical field of organic synthesis, in particular to a method for homogeneously catalyzing and co-producing methyl ethyl carbonate and diethyl carbonate, which comprises the steps of taking organic sulfonate of 0.5-10% of interfacial acid metal ions as a catalyst, reacting for 6-9 hours at 73-80 ℃ according to the molar ratio of dimethyl carbonate to ethanol of 1:5-12, distilling the reacted materials at normal pressure, and collecting a 64-130 ℃ fraction to obtain a mixed fraction containing methyl ethyl carbonate and diethyl carbonate. The technical scheme is superior to the existing catalyst in catalytic activity, compatibility and stability, can efficiently catalyze transesterification to co-produce methyl ethyl carbonate and diethyl carbonate, ensures that the yield of methyl ethyl carbonate is higher than that of diethyl carbonate, and can solve a series of problems existing in the existing catalyst.

Inventors

  • ZENG JIE
  • YANG JIANGUO
  • LIU MINGKAI

Assignees

  • 安徽工业大学

Dates

Publication Date
20260508
Application Date
20260408

Claims (6)

  1. 1. The method for homogeneously catalyzing and co-producing the methyl ethyl carbonate and the diethyl carbonate is characterized by comprising the following steps of: S1, uniformly mixing dimethyl carbonate, ethanol and an organic sulfonic acid metal salt catalyst, and performing transesterification; S2, carrying out normal pressure distillation on the material reacted in the step S1, and collecting the fraction at 64-130 ℃ to obtain the mixed fraction containing the methyl ethyl carbonate and the diethyl carbonate.
  2. 2. The method for homogeneously catalyzing and co-producing methyl ethyl carbonate and diethyl carbonate according to claim 1, wherein in the step S1, the molar ratio of the dimethyl carbonate to the ethanol is 1:5-12, and the amount of the organic sulfonic acid metal salt catalyst is 0.5-10% of the total mass of the dimethyl carbonate and the ethanol.
  3. 3. The method for homogeneously catalyzing and co-producing methyl ethyl carbonate and diethyl carbonate according to claim 1, wherein in the step S1, the organic sulfonic acid metal salt catalyst has a structural formula of Wherein R is H or alkyl, M is hydrogen atom or alkyl, 0-2 natural numbers are taken, X is halogen atom, n is a positive integer of 1-3 and satisfies the relation of m+n=3, and M 2+ is a boundary acid metal ion with 2 unit positive charges.
  4. 4. The method for homogeneously catalyzing and co-producing methyl ethyl carbonate and diethyl carbonate according to claim 3, wherein in the structural formula, X is F, cl or any one of Br, and M 2+ is Zn 2+ 、Fe 2+ 、Co 2+ 、Ni 2+ 、Cu 2+ or any one of Pb 2+ .
  5. 5. The method for homogeneously catalyzing and co-producing methyl ethyl carbonate and diethyl carbonate according to claim 1, wherein in the step S1, the organic sulfonic acid metal salt catalyst is zinc triflate.
  6. 6. The method for homogeneously catalyzing and co-producing methyl ethyl carbonate and diethyl carbonate according to claim 1, wherein in the step S1, the temperature of the transesterification reaction is 73-80 ℃ and the reaction time is 6-9 hours.

Description

Method for coproducing methyl ethyl carbonate and diethyl carbonate by homogeneous catalysis Technical Field The invention relates to the technical field of organic synthesis, in particular to a method for coproducing methyl ethyl carbonate and diethyl carbonate by homogeneous catalysis. Background The methyl ethyl carbonate (EMC) and diethyl carbonate (DEC) have the characteristics of low toxicity and environmental protection, and have wide application in the fields of organic synthesis, environmental protection solvents and the like. Especially in the field of lithium battery electrolyte, the EMC and DEC compound solvent can effectively improve the low-temperature discharge characteristic and the high-temperature cycle performance of the lithium battery, and the content of DEC in the compound solvent is generally less than EMC. At present, the industrial production of EMC and DEC mainly uses the transesterification reaction technical route of ethanol and dimethyl carbonate (DMC), and has the advantages of mild reaction conditions, good safety and environmental protection, etc. Under the condition of high molar ratio of ethanol to DMC, EMC and DEC are co-produced, the product separation procedure can be eliminated, the intensive utilization of shared raw materials and equipment can be realized, the energy consumption can be reduced, the production cost can be reduced, the process management can be simplified, the clean requirements of chemical processes can be met, and a new solution can be provided for cost reduction and efficiency improvement of the lithium battery industry. In order to ensure the production efficiency of the co-production process and meet the application requirements of the product, the DMC raw material is required to have higher conversion rate, and the EMC yield in the co-production process is required to be as high as possible higher than DEC. DMC cannot react directly with ethanol, and the efficient transesterification reaction must be achieved by acceleration of the catalyst, and development of a high-efficiency catalyst has been the focus of research in the field of organic carbonate synthesis. Numerous catalysts useful for transesterification of DMC with ethanol have been reported in the literature, but cost-effective catalysts that are truly commercially valuable are not so much. For a long time, sodium alkoxide compounds represented by sodium methoxide and sodium ethoxide are mainly used as homogeneous catalysts in industrial production. Although the activity of the sodium alkoxide catalyst is relatively higher, the sodium alkoxide is not a completely ideal homogeneous catalyst in the use process, the sodium alkoxide is limited in solubility in a transesterification reaction system of DMC and ethanol, is extremely easy to form scale on the walls of a tower and a kettle, not only reduces the use efficiency of the catalyst, but also increases the heat resistance of the tower kettle and a pipeline, so that the heat exchange efficiency of equipment is reduced, and potential safety hazards are brought in serious cases, (2) the sodium alkoxide can undergo side reaction with water in raw materials and organic carbonate raw materials or products to generate more indissoluble Na 2CO3 solid, so that the catalytic activity is reduced, the catalyst needs to be frequently replaced, and the blockage of the tower kettle and the pipeline is further aggravated. In addition, the disclosed transesterification catalyst has a general technical disadvantage that it is difficult to achieve both high conversion of raw materials and high yield of EMC at a high molar ratio of ethanol to dimethyl carbonate (DMC). The adoption of a higher molar ratio of ethanol to dimethyl carbonate (DMC) is a necessary material condition for realizing the synergistic efficient co-production of EMC and DEC, and in the reaction system, the DMC is subjected to transesterification with ethanol to generate EMC firstly, and then the EMC is subjected to transesterification with ethanol to generate DEC. The two steps of reactions are reversible equilibrium reactions and have similar mechanisms, and the general catalyst has catalytic activity on the two steps of transesterification. Therefore, in case of high molar ratio of ethanol to dimethyl carbonate (DMC), the conversion of raw DMC increases, which entails continuous conversion of EMC to DEC, eventually resulting in EMC yields lower than DEC yields. 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 limited catalyst solubility and poor stability in the existing transesterification synthesis process of methyl ethyl carbonate (EMC) and diethyl carbonate (DEC), and simultaneously solve the problem that the high conversion rate of raw materials and the high yield of product methyl ethyl carbonate are difficult to be simultaneo