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Process for preparing oxalic acid by continuous reaction distillation and hydrolysis of dimethyl oxalate

A technology for decomposing dimethyl oxalate and dimethyl oxalate, which is applied in the direction of carboxylic acid ester/lactone preparation, sustainable manufacturing/processing, separation/purification of carboxylic acid compounds, etc., and can solve the problem of easy clogging of dimethyl oxalate Unable to achieve continuous reaction distillation and other problems, to achieve the effect of improving hydrolysis conversion rate, reducing equipment investment and short reaction time

Active Publication Date: 2017-01-11
FUZHOU UNIV
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Problems solved by technology

[0008] The object of the present invention is to provide a process for preparing oxalic acid by continuous reaction distillation and hydrolysis of dimethyl oxalate, which has the characteristics of fast reaction speed, high reaction conversion rate, simple equipment, low energy consumption, and no environmental pollution in the preparation process. The conversion rate of ester hydrolysis is over 99%; it completely solves the problems that dimethyl oxalate solid cannot realize continuous reaction distillation and dimethyl oxalate is easy to block in the tower.

Method used

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  • Process for preparing oxalic acid by continuous reaction distillation and hydrolysis of dimethyl oxalate

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Effect test

Embodiment 1

[0022] Dimethyl oxalate is dissolved in hot water at 65°C, the molar ratio of water to ester is 4:1, and it is fed from the upper feed port at a feed rate of 1.91g / min. The reactive distillation dividing wall column is a packed column, and the rectification section The number of theoretical plates is 6, and the reaction section and sideline production section The number of theoretical plates is 20, and the stripping section The number of theoretical plates is 3, and the reflux ratio is 2; the lower feed port is fed with water at normal temperature, the feed rate is 1.09g / min, and the total molar ratio of water to ester is 12. Crude methanol is extracted from the top of the reactive distillation dividing wall column at a recovery rate of 0.36g / min, and an aqueous oxalic acid solution containing a small amount of methanol is extracted from the bottom of the reactive distillation dividing wall column at a recovery rate of 2.70g / min. Produced water in the production section...

Embodiment 2

[0024] Dimethyl oxalate is dissolved in hot water at 65°C, the molar ratio of water to ester is 4:1, and it is fed from the upper feed port at a feed rate of 1.91g / min. The reactive distillation dividing wall column is a packed column, the number of theoretical plates in the rectification section ③ is 6, the number of theoretical plates in the reaction section ① and the sideline extraction section ④ is 20, and the number of theoretical plates in the stripping section ② is 3 blocks, the reflux ratio is 2; the lower feed port is fed with water at room temperature, the feed rate is 1.09g / min, and the total molar ratio of water to ester is 15. Crude methanol is extracted from the top of the reactive distillation dividing wall column at a recovery rate of 0.36g / min, and an aqueous oxalic acid solution containing a small amount of methanol is extracted from the bottom of the reactive distillation dividing wall column at a recovery rate of 2.70g / min. Produced water in the production ...

Embodiment 3

[0026] Dimethyl oxalate is dissolved in hot water at 65°C, the molar ratio of water to ester is 4:1, and it is fed from the upper feed port at a feed rate of 1.91g / min. The reactive distillation dividing wall column is a packed column, the number of theoretical plates in the rectification section ③ is 6, the number of theoretical plates in the reaction section ① and the sideline extraction section ④ is 20, and the number of theoretical plates in the stripping section ② is 3 blocks, the reflux ratio is 4; the lower feed port feeds water at room temperature, the feed rate is 1.09g / min, and the total molar ratio of water to ester is 15. Crude methanol is extracted from the top of the reactive distillation dividing wall column at a recovery rate of 0.36g / min, and an aqueous oxalic acid solution containing a small amount of methanol is extracted from the bottom of the reactive distillation dividing wall column at a recovery rate of 2.70g / min. Produced water in the production sectio...

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Abstract

The invention discloses a technique for preparing oxalic acid by performing continuous reaction rectification hydrolysis on dimethyl oxalate. The raw material dimethyl oxalate is subjected to autocatalytic hydrolysis in a continuous reaction rectification dividing wall column to prepare the oxalic acid. The technique has the characteristics of high reaction speed, high reaction conversion rate, simple equipment, low energy consumption and no environmental pollution in the preparation process, and the hydrolysis conversion rate of the dimethyl oxalate is up to 99% above. The technique completely solves the problem that the dimethyl oxalate solid can not be subjected to continuous reaction rectification and can easily block the column.

Description

technical field [0001] The invention belongs to the technical field of hydrolysis of solid dimethyl oxalate, in particular to a process for preparing oxalic acid by continuous reaction distillation and hydrolysis of dimethyl oxalate. Background technique [0002] Oxalic acid is an important organic chemical raw material, often used in the preparation of fine chemical raw materials. Oxalic acid has a wide range of industrial applications, such as widely used in medicine, dye intermediates, extraction of rare metals, and defense industry. There are many existing industrial production methods for oxalic acid, among which sodium formate dehydrogenation is more representative. my country is a big producer of oxalic acid and also a big exporter of oxalic acid. However, the traditional sodium formate dehydrogenation method has been used in oxalic acid production technology for a long time. This technology is not only costly, but also causes equipment corrosion and environmental p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/09C07C51/44C07C55/06
CPCC07C51/09C07C51/44C07C55/06Y02P20/10
Inventor 邱挺黄丹李玲黄智贤杨臣王红星叶长燊
Owner FUZHOU UNIV
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