Interval reaction rectification process for synthesizing methacrylic anhydride

A technology of methacrylic anhydride and methacrylic acid, applied in the field of batch reaction rectification process, can solve problems such as blocking filters, achieve the effects of improving conversion rate and yield, and reducing possibility

Inactive Publication Date: 2013-04-24
FUZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Also, this white powder can clog the filter upstream of the storage tank

Method used

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  • Interval reaction rectification process for synthesizing methacrylic anhydride

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Attached figure 1 Shown technological process, concrete steps are as follows:

[0028] 1) After the raw materials acetic anhydride and methacrylic acid are mixed with the polymerization inhibitor, they are fed into the tower kettle through the pipeline 4. The molar ratio of the raw materials acetic anhydride and methacrylic acid is 1:1.5~1:4, and the feeding method is one-time feeding.

[0029] 2) Turn on the heating and control the initial top pressure at 10kPa. Then in the reaction process, the operating pressure of the tower is continuously reduced (taking the steam at the top of the tower as the standard, and when the steam at the top of the tower is no longer condensed, the vacuum degree of the tower is appropriately increased), so that one of the products, acetic acid, is continuously distilled from the rectification The tower steams out.

[0030] 3) When there is reflux at the top of the tower, dissolve part of the polymerization inhibitor with acetic acid and ...

Embodiment 2

[0037] Similar to the operation method of Example 1, the molar ratio of raw materials acetic anhydride and methacrylic acid is 1:1.5~1:4, and the feeding method is one-time feeding.

[0038] The reaction results are as follows: the reaction time is 5.58 hours, the conversion rate of methacrylic acid is 99.11%, the purity of acetic acid at the top of the tower is 99.82%, and the reaction yield of methacrylic anhydride is 85.99%.

Embodiment 3

[0040] Similar to the operation method of Example 1, the polymerization inhibitor is 2,4-di-tert-butyl-p-cresol (6BX), 2,6-di-tert-butyl-6-p-cresol (BHT), phosphoric acid triester (TOP ), the mixing ratio of the three is still mass ratio 1:2:3, and the amount of polymerization inhibitor is 0.5% of the raw material liquid quality. When the top of the tower starts to extract, set the reflux ratio to 1. After 2.5 hours of extraction, adjust the reflux ratio to 1.5. After continuous extraction for 1 hour, adjust the reflux ratio to 3 until the end of the reaction. Other operating conditions are the same as Example 1.

[0041] The reaction results are as follows: the reaction time is 4.75h, the conversion rate of methacrylic acid is 99.2%, the purity of acetic acid at the top of the tower is 99.1%, and the reaction yield of methacrylic anhydride is 86.10%.

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Abstract

The invention discloses an interval reaction rectification process for synthesizing methacrylic anhydride. Reaction rectification equipment is an interval reaction rectification tower; and a reaction is mainly carried out in a tower kettle of the rectification tower. The process adopts a reaction rectification technology to move away byproduct acetic acid from a reaction system in time so that the reaction is carried out in a forward direction; and the conversion rate of methacrylic acid is improved. A polymerization inhibitor is respectively added from the tower kettle and a reflowing opening of the tower so as to effectively prevent the methacrylic acid from being polymerized. The methacrylic anhydride synthesized by the interval reaction rectification process has the characteristics of high reaction conversion rate, high purities of the acetic acid at the tower top, stable product quality and the like. The conversion rate of the methacrylic anhydride obtained by the process is more than 98% and the reaction yield of the methacrylic anhydride reaction exceeds 80%.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a batch reaction rectification process for synthesizing methacrylic anhydride. Background technique [0002] Methacrylic anhydride is a strong esterification agent, and it is a necessary reagent for the preparation of methacrylic acid thioester, methacrylamide and methacrylic acid ester (especially the ester of tertiary alcohol). The coupling agent is used in the synthesis of materials such as photocurable coatings and cross-linked resins, and can also be used as a raw material for the synthesis of special fine chemicals, which has broad market application prospects. [0003] At present, the synthesis technology of methacrylic anhydride is mainly divided into two categories: the first category is the preparation of methacrylic anhydride with metal methacrylic acid salt and chloroformate as raw materials. The second type is to use methacrylic acid and acetic anhydride...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/04C07C57/07C07C51/56C07C51/573
Inventor 邱挺王碧玉黄智贤李玲郑辉东曾瑜
Owner FUZHOU UNIV
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