A process of preparing dimethyl carbonate by oxidative carbonylation of methanol

Abstract

A process of preparing dimethyl carbonate by oxidative carbonylation of methanol adopts a catalytic rectification column as the main reacting device. The upper part of the catalytic rectification column is adopted as a rectification section, the middle part of the catalytic rectification column is adopted as a reacting section and the lower part of the catalytic rectification column is adopted as a distillation section. A reboiler is disposed at the bottom of the distillation section. A condensation reflux device is disposed at the top of the rectification section. Liquid methanol is fed from the top of the reacting section of the catalytic rectification column. Pressurized CO and nitrogen are fed from the bottom of the distillation section. O2 is divided into 1-5 parts and fed from the reacting section in a staged manner. Descending methanol and ascending CO / O2 in the reacting section are subjected to countercurrent contact, and react continuously to produce the dimethyl carbonate product in a catalyst filler bed layer in the reacting section. The rectification section mainly separates unreacted methanol from byproducts with low boiling points. A crude dimethyl carbonate product is obtained by rectification in the upper part of the distillation section. The process is advantageous in that the synthetic process is simple, the methanol conversion rate is high and purity of the dimethyl carbonate product is high.

Description

Technical field [0001] The invention belongs to a process for synthesizing dimethyl carbonate, and specifically relates to a process for synthesizing dimethyl carbonate by a methanol liquid phase oxidative carbonylation method. technical background [0002] Dimethyl carbonate (DMC) is an important organic synthesis intermediate because it contains methyl, methoxy, carbonyl, ester and other functional groups in its molecule, which can replace phosgene and dimethyl sulfate. A variety of highly toxic chemicals are widely used in the preparation of high-performance resins, dye intermediates, drugs, food preservatives, lubricating additives and other fields. Because of the high oxygen content in the molecule, it can increase the octane number and be used as a gasoline additive. DMC has good solvent properties and low vapor pressure, and can be used as a solvent for lithium battery liquid components and special coatings. The preparation methods include phosgene method, transesterific...

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Problems solved by technology

However, the reaction and separation process is relatively complicated, and the DMC content in the crude product separated after the system is stable is only 19.2%.

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