Method for producing oxalic ester by gas phase CO coupling

Abstract

The invention relates to a method for producing oxalic ester by gas phase CO coupling, which mainly solves the technical problems of low oxygen removal rate of raw materials, low selectivity of target products and low space-time yield of the oxalic ester in the prior art. The method comprises the following steps: (a) firstly, a CO gas raw material containing oxygen and NO gas enter a deoxidizing reactor and contact with a molecular sieve catalyst, and the oxygen in the raw material reacts with the NO to generate a gas phase effluent I containing NO2, unreacted NO and CO; (b) the gas phase effluent I and nitrous acid ester enter a coupling reactor and contact with a palladium-containing catalyst to react to generate an effluent II containing the oxalic ester; and (c) the effluent II of the oxalic ester is separated to obtain the oxalic ester product and a gas phase effluent III containing nitrogen oxides, wherein the mol ratio of the NO to oxygen in the CO gas raw material containing the oxygen in the step (a) is 4-100:1. By using the technical scheme, the problems are better solved and the method can be used for the industrial production for increasing the yield of the oxalic ester.

Description

technical field

[0001] The present invention relates to a kind of CO gas-phase coupling production method of oxalate ester, especially about the CO raw material that contains oxygen reacts with NO to remove oxygen first and then is coupled with methyl nitrite or ethyl nitrite to produce dimethyl oxalate or Diethyl oxalate method. Background technique

[0002] Oxalate is an important organic chemical raw material, which is widely used in the fine chemical industry to produce various dyes, medicines, important solvents, extractants and various intermediates. In the 21st century, oxalate, as a degradable and environmentally friendly engineering plastic monomer, has received extensive international attention. In addition, oxalic acid can be obtained by normal pressure hydrolysis of oxalate, and oxalamide can be obtained by normal pressure ammonia solution. Oxalate can also be used as a solvent to produce pharmaceutical and dye intermediates, etc., such as various condensation ...