Method for preparing oxalate by coupling reaction of CO in gaseous phase

Abstract

The invention relates to a method for producing oxalic ester by CO gaseous phase coupling, which mainly solves the problems of low selectivity of target products and low single-pass conversion in the prior art. The method adopts a technical proposal that raw materials of nitrous acid ester-containing gas and CO are introduced into a reacting-separating tower and are contacted with palladium-containing catalysts under the condition that the temperature is between 60 and 160 DEG C, the reaction contact time is between 0.5 and 6 seconds, and the reaction pressure is between 0.05 and 1.5 MPa, a gas-liquid mixture containing oxalic ester is generated after the reaction; meanwhile, gas-liquid separation is performed in the reacting-separating tower, an oxalic ester product is obtained at the bottom of the tower, and gaseous phase effluenst containing unreacted nitrous acid ester and CO are obtained at the top of the tower. The method solves the problems well and can be used in industrial production for increasing the yield of the oxalic ester.

Description

technical field

[0001] The invention relates to a method for producing oxalate by gas-phase coupling of CO, in particular to a method for producing dimethyl oxalate or diethyl oxalate by coupling CO with methyl nitrite or ethyl nitrite. 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 reactions with fatty acid esters, cyclohexylacetophenone, amino alcohols, and many heterocyclic ...