Preparation of maleic acid di-methyl ester

A technology of dimethyl maleate and monomethyl maleate, which is applied in the field of preparing dimethyl maleate by reacting maleic anhydride with methanol, can solve the problem that monoesterification and diesterification cannot be used at the same time, and the production process complex issues

Inactive Publication Date: 2008-12-03
SHANGHAI HUAYI ENERGY CHEM
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  • Abstract
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AI Technical Summary

Problems solved by technology

[0021] The technical problem to be solved by this invention is to provide a kind of preparation method of dimethyl maleate, to overcome prior art monoesterification and double esterification reaction are carried out in two separate reaction towers, make production technology more complicated , and can not simultaneously utilize the defects of mono-esterification and diesterization reaction heat

Method used

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  • Preparation of maleic acid di-methyl ester
  • Preparation of maleic acid di-methyl ester

Examples

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Embodiment 1

[0047] Continuously add the mixture of methyl alcohol and maleic anhydride in the tower still of catalytic distillation tower (15 trays, resin catalyst of tray packing, the trade mark is DNW-1), the mol ratio of methyl alcohol and maleic anhydride is 4: 1, Monoesterification reaction temperature 120 ℃ (overhead pressure is 1.3 bar, and tower pressure drop is 1.7 bar), and the heat of esterification reaction vaporizes excess methyl alcohol, wherein the mol ratio of the vapor methanol that produces and monomethyl maleate is 2.2: 1.

[0048] The liquid phase reaction product containing monomethyl maleate is added to the third plate, and the feeding flow is controlled so that the residence time of the monoesterification reaction and the double esterification reaction are 30 minutes and 2 hours respectively. At the bottom of the catalytic distillation tower 15 tray places obtain product, wherein dimethyl maleate content 97.6%, methanol content 1.4%, water content 1%; Obtain excess ...

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Abstract

The invention relates to an improved method for preparing dimethyl maleate through reaction of maleic anhydride and methanol. The method completes preparation of the dimethyl maleate in a single catalysis and distillation tower, namely the method comprises the following steps that: mono-esterification reaction is performed in a tower kettle of the catalysis and distillation tower, and reaction heat is used for directly generating methanol steam; and simultaneously, liquid-phase reaction products containing monomethyl maleate are added to the upper part of the catalysis and distillation tower through a pipeline and flow down and generate counter current contact with the gradually dried methanol steam which flows up to complete the reaction. According to the method, not only the esterification reaction heat can be effectively utilized but also heat exchange and mono-esterification reaction equipment in the prior art can be saved, thereby the flow is more compact and more reasonable.

Description

technical field [0001] The invention belongs to the field of organic chemistry and relates to an improved method for preparing dimethyl maleate by reacting maleic anhydride with methanol. Background technique [0002] Dimethyl maleate is an important organic chemical raw material, especially through catalytic hydrogenation, it can be used to produce 1,4-butanediol, tetrahydrofuran and γ-butyrolactone, so that maleic anhydride and methanol can be reacted to produce maleic acid The dimethyl ester method has received a great deal of attention. [0003] The reaction of maleic anhydride with methanol to prepare dimethyl maleate can be described by the following equation. [0004] [0005] The above reactions are all exothermic reactions. Under the reaction conditions, the thermal effect of the monoesterification reaction in the equation (1) is 35kJ / mol, and the thermal effect of the double esterification reaction in the equation (2) is 16kJ / mol. Monoesterification is an irre...

Claims

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Application Information

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IPC IPC(8): C07C69/60C07C67/08
Inventor 何明康赵正康张旭红杨菊群
Owner SHANGHAI HUAYI ENERGY CHEM
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