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Method for preparing diethyl carbonate by two-step coupling reaction

A technology of diethyl carbonate and coupling reaction, applied in the preparation of organic compounds, chemical instruments and methods, preparation of carbonate/haloformate, etc., can solve the problem of low yield of urea alcoholysis method and expensive raw materials of transesterification method Economic and other issues, to achieve the effect of convenient separation

Inactive Publication Date: 2008-12-24
XI AN JIAOTONG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The purpose of the present invention is to try to develop a new process in order to increase the yield of diethyl carbonate, which solves the problem of low yield of urea alcoholysis and solves the problem of expensive raw materials and poor economy of transesterification

Method used

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  • Method for preparing diethyl carbonate by two-step coupling reaction
  • Method for preparing diethyl carbonate by two-step coupling reaction

Examples

Experimental program
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Effect test

Embodiment 1

[0024] 0.25 moles of urea, 0.75 moles of ethanol, 2.5 moles of ethylene glycol, and 20.45 grams of zinc oxide catalyst were added to the reactor 1, and the nitrogen pressure was filled to 0.6 MPa. After heating the mixed solution to 170°C, turn on the agitator 5, start the reaction by timing, and control the pressure in the reactor to 2.2Mpa. After the reaction was completed, the reactor was cooled to room temperature, and gas chromatography was used to analyze the composition of the mixture in the reactor to determine the yield of the product. After 5 hours of reaction, the yield of diethyl carbonate reached a maximum of 78%.

Embodiment 2

[0026] Add 0.25 moles of urea, 0.75 moles of ethanol, 1.5 moles of ethylene glycol, and 22.75 grams of zinc oxide catalyst into reactor 1. The initial nitrogen pressure is 0.7 MPa, the reaction temperature is 170 ° C, the stirring speed is 700 rpm, and the pressure in the reactor is maintained at 2.5Mpa, reaction 4 hours diethyl carbonate yield is 53.7%, all the other conditions are with embodiment 1.

Embodiment 3

[0028] Add 0.25 moles of urea, 1.75 moles of ethanol, 2.1 moles of ethylene glycol, and 20.95 g of zirconia catalyst into the reaction kettle, and the initial nitrogen pressure is 0.8 MPa. After heating the mixture to 180 ° C, under the action of stirring speed of 600 rpm react. The pressure in the reactor was maintained at 3.0Mpa, and after 4 hours of reaction, the yield of DEC was 49.13%, and the other conditions were the same as in Example 1.

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Abstract

The invention discloses a method for preparing diethyl carbonate by two steps of coupling reaction. The method takes carbamide, ethanol and glycol as raw materials and takes an appropriate metal oxide as a catalyst. The catalyst, the carbamide, the ethanol and the glycol are added into a reaction kettle according to a certain proportion; the carbamide and the glycol have alcoholysis reaction at a temperature of between 160 and 180 DEG C and a pressure of between 2.2 and 3.5MPa to produce an intermediate product of ethylene carbonate, and the ethylene carbonate and the ethanol have ester exchange reaction to produce diethyl carbonate. Compared with the sole carbamide alcoholysis method, the two steps of the coupling reaction effectively reduce gibbs free energy of the reaction. The produced target product of diethyl carbonate has a yield coefficient up to 78 percent. Meanwhile, the process does not produce water, thereby bringing convenience to the subsequent separation and the glycol can be recycled.

Description

technical field [0001] The invention relates to a method for preparing diethyl carbonate, in particular to a method for preparing diethyl carbonate by using urea, ethanol and ethylene glycol as raw materials through two-step coupled reactions. Background technique [0002] Diethyl carbonate (DEC) is an important environmentally friendly organic carbonate with low toxicity. Its molecular formula is C 5 h 10 o 3 , the relative molecular weight is 118.13, and the structural formula is: [0003] [0004] Because of its molecular structure containing ethyl, ethoxy, carbonyl and carbonyl ethoxy, diethyl carbonate can carry out ethylation reaction, ethoxylation reaction, carbonylation reaction and carbonyl ethoxylation reaction, and also It can carry out condensation reaction and condensation cyclization reaction with various organic compounds. For example, diethyl carbonate can react with compounds containing active hydrogen groups such as alcohols, phenols, amines, and es...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/96C07C68/00
Inventor 杨伯伦邱鹏翟晓伟
Owner XI AN JIAOTONG UNIV
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