Method and device for co-producing dimethyl carbonate and dimethyl oxalate

Abstract

The invention discloses a method and a device for co-preparing di(C1-3) alkyl carbonate and di(C1-3) alkyl oxalate. The method comprises the following steps of: a) separating a product of a di(C1-3) alkyl carbonate synthesis reactor into a first liquid phase and a first gas phase; b) separating a product of a di(C1-3) alkyl oxalate synthesis reactor into a second liquid phase and a second gas phase; c) conveying the first liquid phase to a first rectifying tower from the tower top, conveying the combined first gas phase and second gas phase to the first rectifying tower from the middle lower part of the tower, conveying the second liquid phase to the first rectifying tower from the tower bottom, and generating basically pure di(C1-3) alkyl oxalate fraction from the bottom of the first rectifying tower during rectifying; d) separating the overhead fraction produced in the first rectifying tower into a third liquid phase and a third gas phase; and e) conveying the third liquid phase to a second rectifying tower from the middle part of the tower, and generating basically pure di(C1-3) alkyl carbonate from the bottom of the second rectifying tower. Only three rectifying towers are designed in the whole process through reasonable process design, so the energy requirement and operation expense are effectively reduced, and the equipment investment expense is saved.

Description

technical field

[0001] The invention relates to a method and a device for coproducing dimethyl carbonate and dimethyl oxalate from carbon monoxide, methanol and oxygen. It belongs to the technology of preparing dimethyl carbonate and dimethyl oxalate by oxidative carbonylation of methanol. technical background

[0002] Dimethyl carbonate (DMC) is an important organic synthesis intermediate with low toxicity. It is a "green" chemical product with development prospects. It can replace toxic substances such as phosgene to synthesize polycarbonate, and can be used in gasoline Additives etc.

[0003] Dimethyl oxalate (DMO) is an intermediate product in the synthesis of ethylene glycol by oxidative carbonylation of methanol. Japan UBE Company (EP0046598, 1982; EP0086370, 1983) and U.S. Union Carbide Corporation (EP0057630, 1982) have announced the preparation of dimethyl oxalate or diethyl oxalate by means of the CO coupling reaction that occurs with methyl nitrite or ethyl nitr...

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