Process and production system for synthesizing dimethyl oxalate or diethyl oxalate and coproducing oxalic acid

Abstract

The invention discloses a process and a production system for synthesizing dimethyl oxalate or diethyl oxalate and coproducing oxalic acid. The method comprises the following steps of: reacting nitrogen oxide with alcohol in an esterification reactor to form nitrite, adding the nitrite into a gas phase coupling carbonylation reactor, and connecting the gas phase coupling carbonylation reactor with a condenser and an oxalate hydrolysis reactor. After being condensed by the condenser, outlet gas of the gas phase coupling carbonylation reactor is condensed into liquid-phase or solid-phase oxalate; the oxalate in the gas phase enters the oxalate hydrolysis reactor to generate the oxalic acid and the alcohol of corresponding ester; the ester solution of the corresponding ester can enter the subsequent esterification reactor for reaction; and the amount of the oxalate which enters the gas phase can be adjusted by adjusting the temperature of the condenser so as to adjust the distribution of the synthetic amount of the oxalate and the oxalic acid. Nitrogen oxide-containing noncondensable gas which passes through the oxalate hydrolysis reactor is recycled to enter the esterification reactor so as to realize the recycling of the nitrogen oxide. The process and the production system for synthesizing the dimethyl oxalate or the diethyl oxalate and coproducing the oxalic acid have low energy consumption and high productivity and meet the industrial requirement.

Description

technical field [0001] The invention relates to a process for synthesizing dimethyl oxalate or diethyl oxalate and co-producing oxalic acid, more specifically, to a process for synthesizing dimethyl oxalate or diethyl oxalate and co-producing carbon monoxide and oxygen through nitrite esters Oxalic acid process. Background technique [0002] Oxalic acid, dimethyl oxalate and diethyl oxalate are all important organic chemical raw materials. Oxalic acid is widely used in the fields of chemical synthesis, pharmaceuticals, extraction and refining of rare earth elements, metal treatment and cleaning, and polymer synthesis, while dimethyl oxalate The low-pressure hydrogenation of esters and diethyl oxalate can produce ethylene glycol, an important chemical raw material, which has attracted widespread attention in the chemical industry. [0003] The traditional oxalic acid production methods are sodium formate method, ethylene glycol oxidation method, carbohydrate oxidation method...

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Problems solved by technology

[0013] The purpose of the present invention is to overcome the high energy consumption and separation cost in the process of preparing methyl oxalate or ethyl oxalate by using CO as a raw material through methyl nitrite or ethyl nitrite, and the circulation system of CO oxidation coupling is prepared under the action of a catalyst. Increase and cause technical problems such as follow-up equipment corrosion, provide a method for synthesizing dimethyl oxalate or diethyl oxalate and simultaneously co-producing oxalic acid suitable for industrialized large-scale production

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