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Primary concentration and purification method for trioxymethylene after synthesizing

A technology of paraformaldehyde and a new method, applied in the direction of organic chemistry, etc., can solve the problems of difficult removal, impact on subsequent processes, high cost, etc., and achieve the effect of overcoming the bottleneck of large-scale production, simple equipment, and reduced energy consumption

Inactive Publication Date: 2008-02-13
ZHEJIANG SANPO POLYMER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Usually the concentration of paraformaldehyde is to adopt the method of solvent extraction, and its disadvantage one is that solvent removal is difficult; the other is that even if the solvent is removed by rectification, it is not easy to remove completely, which will affect the follow-up process; the third is that the solvent consumption is large, Recycling is difficult and pollutes the environment; Fourth, the cost is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] In the presence of a catalyst, formaldehyde with a concentration of 85% is reacted in a trioxymethylene synthesis reactor under the conditions of 140° C. and 1.0Mpa to generate a gas-liquid mixture containing formaldehyde, water, trioxymethylene and other small amounts of organic substances. The formaldehyde content is 40%, which is sent to the gas-liquid separator for gas-liquid separation. The generated gas phase part is sent to the rectification tower, and rectified under the conditions of 150°C, 1.5Mpa, and a reflux ratio of 100; the liquid phase part is returned to the trioxymethylene synthesis reactor. The top product obtained after rectification enters the condenser, cools to 145°C and then enters the absorption tower. The temperature of the absorption tower is controlled at 150°C and the pressure is controlled at 1.0Mpa; the kettle liquid obtained after the rectification is returned to the trioxymethylene synthesis reactor. After being absorbed by the absorption...

Embodiment 2

[0021] In the presence of a catalyst, formaldehyde with a concentration of 30% is reacted in a trioxymethylene synthesis reactor at 85°C and 0Mpa to generate a gas-liquid mixture containing formaldehyde, water, trioxymethylene and other small amounts of organic matter, among which trioxymethylene The content is 8%, and it is sent to a gas-liquid separator for gas-liquid separation. The gas phase part produced is sent to the rectification tower, and rectified under the conditions of 80°C, 0Mpa, and reflux ratio of 0.1; the liquid phase part is returned to the trioxymethylene synthesis reactor. The top product obtained after rectification enters the condenser, and then enters the absorption tower after cooling to 55°C. The temperature of the absorption tower is controlled at 80°C and the pressure is controlled at 0Mpa; the kettle liquid obtained after the rectification is returned to the trioxymethylene synthesis reactor. After being absorbed by the absorption tower, the top gas...

Embodiment 3

[0023] In the presence of a catalyst, formaldehyde with a concentration of 50% is reacted in a trioxymethylene synthesis reactor under the conditions of 100° C. and 1.0Mpa to generate a gas-liquid mixture containing formaldehyde, water, trioxymethylene and other small amounts of organic substances. The formaldehyde content is 20%, which is sent to the gas-liquid separator for gas-liquid separation. The gas phase part produced is sent to the rectification tower, and rectified under the conditions of 100°C, 0.8Mpa, and a reflux ratio of 10; the liquid phase part is returned to the trioxymethylene synthesis reactor. The top product obtained after rectification enters the condenser, and then enters the absorption tower after cooling to 90°C. The temperature of the absorption tower is controlled at 100°C and the pressure is controlled at 0.8Mpa; the still obtained after rectification is returned to the trioxymethylene synthesis reactor. After being absorbed by the absorption tower,...

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Abstract

The invention discloses a new method for preliminary concentration and purification of paraformaldehyde after synthesis, which belongs to the technical field of concentration and purification of crude paraformaldehyde. The mixture is sent to the rectification tower for rectification; the top product obtained after rectification enters the condenser, and enters the absorption tower after cooling; the rectification tower still liquid returns to the paraformaldehyde synthesis reactor; after being absorbed by the absorption tower, the absorption tower The top gas and the bottom product enter the pre-concentration tower together for rectification treatment, and the solution obtained at the bottom of the pre-concentration tower is used as the reflux of the synthesis rectification tower and the absorption liquid of the absorption tower; The top product is sent to the concentration tower for concentration, and formaldehyde solution is obtained at the bottom of the concentration tower; the top product obtained from the concentration tower enters the light component removal tower, and the top of the light component removal tower obtains combustible waste liquid, and the bottom of the tower obtains 30-90% aqueous solution of paraformaldehyde. The invention has large output and low operation cost.

Description

technical field [0001] The invention discloses a new method for preliminary concentration and purification after trioxymethylene synthesis, and belongs to the technical field of thick trioxymethylene concentration and purification processes. Background technique [0002] In the process of trioxymethylene synthesis, crude trioxymethylene contains a large amount of water and formaldehyde, and the purpose of preliminary concentration and purification is to separate trioxymethylene from a large amount of water and formaldehyde. Usually, the method of solvent extraction is used for the concentration of paraformaldehyde. The disadvantage is that solvent removal is difficult; Recycling is difficult and polluting the environment; fourth, the cost is high. Therefore, it is necessary to develop a new method for separation and concentration of crude trioxymethylene. SUMMARY OF THE INVENTION [0003] In order to overcome the above-mentioned deficiencies of the prior art, the present...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D323/06
Inventor 周赞斌傅大放程晔华王明淦
Owner ZHEJIANG SANPO POLYMER
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