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Semi-continuous reaction distillation process for producing carbonic ester

A reactive distillation and semi-continuous technology, applied in the carbonate field, can solve the problems of difficulty for new entrants to enter the linear carbonate market, increase in impurity generation and equipment costs, and high threshold for capital investment, so as to reduce equipment investment and operating costs, reduce Equipment investment cost, high efficiency

Pending Publication Date: 2021-09-17
张文进 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This will increase the generation of impurities and equipment costs, the capital investment threshold is high, and it is difficult for new entrants to enter the linear carbonate market

Method used

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  • Semi-continuous reaction distillation process for producing carbonic ester
  • Semi-continuous reaction distillation process for producing carbonic ester
  • Semi-continuous reaction distillation process for producing carbonic ester

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0047] Example 1: Production of high-purity EMC and DEC from DMC

[0048] Such as figure 1 As shown, a conventional batch distillation system is characterized in that the still pot is equipped with a stirrer and used as a reactor. The reactor was filled with DMC and ethanol in a molar ratio of 1:1. Sodium methoxide (dissolved in methanol) was used as catalyst. The operation steps are as follows:

[0049] (1) The reactor is heated to a reaction temperature of 65-85°C. The distillation column was operated at total reflux until the temperature at the top of the column reached 63.5° C. (DMC-methanol azeotrope temperature at atmospheric pressure). Then continue to carry out reactive distillation at a reflux ratio of 3:1, and adjust the reactor temperature so that the temperature at the top of the tower is controlled at about 63.5°C.

[0050] (2) When the reaction temperature begins to rise and the flow at the top of the tower begins to decrease, start to pump fresh DMC raw mat...

example 2

[0062] Example 2, such as image 3 As shown, the conventional batch distillation unit used in Example 1 was changed into a semi-continuous distillation unit. A recirculation pump is added to pump the reaction mixture into the column or into the reactor vapor space to enhance the heat and mass transfer of the reactive distillation. Heat exchange can be added to the circulation loop to increase heating / cooling capacity, but this heat exchanger is optional depending on other design parameters of the plant and the characteristics of the reaction.

[0063] The recycle loop entry point can be any point in the distillation column. By introducing the reaction mixture into the column, which thus has a stripping and rectifying section, the column batch column can be used as a continuous distillation column 13, thereby increasing the efficiency of the column. In a typical batch distillation operation, the column has only a rectifying section and no stripping section. This recirculatio...

example 3

[0077] Example 3, Preparation of Dimethyl Carbonate (DMC) from Ethylene Carbonate (EC)

[0078] Such as Figure 6 As shown, a set of reactive distillation column is used to make industrial-grade EC react with industrial-grade methanol to produce DMC. The catalyst used is still sodium methoxide. The reactive distillation system adds a recirculation loop that enters the top of the reaction section of the tower, as Figure 6 shown. The operating steps of this system are similar to Example 2.

[0079] (1) Add EC and methanol at a molar ratio of 1:2 to the reactor. The catalyst sodium methoxide was added to speed up the reaction. Heating to 65-80 ° C, so that the distillation column is in a state of complete reflux. When the temperature at the top of the tower reaches 63.5°C, change to operate at a reflux ratio of 3:1, and take out the top product (ie DMC / MeOH azeotrope).

[0080] (2) When the overhead flow drops and the temperature begins to drop, start introducing fresh me...

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Abstract

The invention relates to the technical field of carbonic ester, in particular to a semi-continuous reaction distillation process for producing carbonic ester, which comprises the following steps of: adding one or more reactants into a reactor or a distillation tower in the reaction distillation process by using intermittent distillation equipment or improved continuous distillation equipment, so as to completely convert the other reactant; then conducting distilling, distilling out light impurities from the top of the tower, completely retaining the residual light impurities in the distillation tower above the reaction kettle, and sending the reacted mixture without light components from the distillation kettle (reactor) to another set of distillation unit for separation, or feeding the materials into a storage tank firstly and then conducting rectification and separation by using the same set of reaction distillation equipment to produce high-purity DMC, EMC and DEC. The process maximizes the conversion of one or more reactants so as to avoid the formation of azeotropes.

Description

technical field [0001] The invention relates to the technical field of carbonates, in particular to a semi-continuous reactive distillation process for producing carbonates. Background technique [0002] Organic carbonates, such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), have been produced industrially for many years. Among them, ethylene carbonate and propylene carbonate generate 1,2 through the reaction of CO2 and ethylene oxide (EO) in the presence of a catalyst. [0003] [0004] Dialkyl carbonates, such as DMC, EMC and DEC, are usually produced by the transesterification of EC or PC with methanol or ethanol3 or mixtures of methanol and ethanol, the by-product of which is ethylene glycol (EG) or propylene glycol (PG). These dialkyl carbonates can also be prepared by transesterification of a carbonate with an alcohol. The following are some examples of transesterification ...

Claims

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Application Information

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IPC IPC(8): C07C69/96C07C68/06C07C68/065C07C68/08C07D317/36
CPCC07C68/06C07C68/065C07C68/08C07D317/36C07C69/96Y02P20/10
Inventor 张文进耿昆仑
Owner 张文进
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