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Intermittent reaction-continuous reaction rectification combined process for catalytic synthesis of oxalic acid

A technology of reactive distillation and combined process, which is applied in the chemical industry, sustainable manufacturing/processing, separation/purification of carboxylic acid compounds, etc., and can solve the problems of complicated purification and separation of follow-up products, long reaction time, high water-ester ratio, etc. , to save energy and investment, reduce energy consumption, and reduce water-ester ratio

Active Publication Date: 2015-09-09
FUZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there is little research on the process of hydrolyzing dimethyl oxalate. The main reaction device is a hydrolysis reactor or a batch reactor. Disadvantages such as complicated purification and separation and high energy consumption

Method used

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  • Intermittent reaction-continuous reaction rectification combined process for catalytic synthesis of oxalic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Water and dimethyl oxalate are mixed in a molar ratio of 5:1, and enter the batch reactor for preliminary reaction at 65°C. After 3 hours of reaction, the feed is fed to the next-door rectification tower, and the reaction liquid in the batch reactor is fed from the upper feed port. Continuously enter the reaction zone (zone b) of the dividing wall tower RD, and the normal temperature water with a corresponding ratio (total water-to-ester ratio of the whole process is 10:1) enters the tower from the lower feed port of the reaction zone (zone b), and the top of the tower conveys the reaction process The methanol generated in the reactor is continuously discharged, part of the water is continuously produced from the lower part of the rectification zone (zone d) on the right side of the dividing wall, and oxalic acid, excess water and a very small amount of methanol are continuously produced from the tower kettle. The specific parameters are as follows:

[0030] (1) The volu...

Embodiment 2

[0037] Water and dimethyl oxalate are mixed in a molar ratio of 4:1, and enter the batch reactor for preliminary reaction at 60°C. After about 4 hours, the feed is fed to the next-door rectification tower, and the reaction liquid in the batch reactor is fed from the upper feed port. Continuously enter the reaction zone (zone b) of the dividing wall tower RD, and the normal temperature water with the corresponding ratio (total water-to-ester ratio of the whole process is 10:1) enters the tower from the lower feed port of the reaction zone (zone b), and the top of the tower conveys the reaction process The methanol generated in the reactor is continuously discharged, part of the water is continuously produced from the lower part of the rectification zone (zone d) on the right side of the dividing wall, and oxalic acid, excess water and a very small amount of methanol are continuously produced from the tower kettle. The specific parameters are as follows:

[0038] (1) The volum...

Embodiment 3

[0045]Water and dimethyl oxalate are mixed in a molar ratio of 5:1, and enter the batch reactor for preliminary reaction at 65°C. After 3 hours of reaction, the feed is fed to the next-door rectification tower, and the reaction liquid in the batch reactor is fed from the upper feed port. Continuously enter the reaction zone (zone b) of the dividing wall tower RD, and the normal temperature water with the corresponding ratio (total water-to-ester ratio of the whole process is 11:1) enters the tower from the lower feed port of the reaction zone (zone b), and the top of the tower conveys the reaction process The methanol generated in the reactor is continuously discharged, part of the water is continuously produced from the lower part of the rectification zone (zone d) on the right side of the dividing wall, and oxalic acid, excess water and a very small amount of methanol are continuously produced from the tower kettle. The specific parameters are as follows:

[0046] (1) The vol...

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Abstract

The invention discloses an intermittent reaction-continuous reaction rectification combined process for catalytic synthesis of oxalic acid. The process particularly comprises the following steps: (1) continuously feeding materials into a reactive dividing-wall rectification tower in a double batch reactor switching mode; (2) enabling dimethyl oxalate and water to enter a batch reactor to react primarily, wherein the equilibrium conversion rate reaches 50%-60%; and (3) continuously feeding reaction solution into a left-side reaction section ( zone b) of the reactive dividing-wall rectification tower from an upper feeding opening, continuously feeding normal-temperature water into the reactive dividing-wall rectification tower from a lower feeding opening of the zone b, and continuously discharging methyl alcohol produced in the reaction process from the tower top, wherein due to the discharging of methyl alcohol, the reaction proceeds to production of oxalic acid until dimethyl oxalate is completely hydrolyzed and the conversion rate can reach 99.5% or above. By virtue of the reactive dividing-wall rectification tower, the synthesis reaction and product separation and purification are implemented in the same tower, the existing process flow is simplified, and energy consumption and investment can be lowered. The intermittent reaction-continuous reaction rectification combined process for catalytic synthesis of oxalic acid has the characteristics of no addition of extra additives, high reaction speed, high conversion rate, low water-ester ratio, simple product separation operation, low energy consumption and the like.

Description

technical field [0001] The invention belongs to the technical field of preparation of oxalic acid, and in particular relates to a combined process of catalyzing and synthesizing oxalic acid by batch reaction and continuous reaction rectification. Background technique [0002] Oxalic acid is an important organic chemical raw material, which is widely used in medicine, textile, organic synthesis, rare earth element refining and leather industries. It can also be used in the synthesis of dye intermediates, purification of metal equipment, preparation of catalysts, synthesis of oxalic acid derivatives, Synthetic chemical intermediates and some necessary reagents, etc. [0003] At present, the main production methods of oxalic acid used in China are sodium formate method and nitric acid oxidation method. These two methods not only have high production costs but also seriously pollute the environment. Although most enterprises have made corresponding improvements to these...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C55/06C07C51/09C07C51/44
CPCC07C51/09C07C51/44C07C55/06Y02P20/10
Inventor 邱挺周丽华黄智贤李玲王红星杨臣叶长燊
Owner FUZHOU UNIV
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