Preparation method of active large monomers by dehydration and esterification

A technology of active macromonomer, which is applied in the field of preparation of active macromonomer by dehydration esterification, can solve the problems affecting product quality, etc., and achieve high concrete water-reducing rate, high unsaturated bond content, and easy operation Effect

Inactive Publication Date: 2012-03-21
深圳市五山新材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, esterification dehydration generally adopts solvent dehydration and negative pressure dehydration. Among them, solvent dehydration contains toxic solvents xylene or benzene, and the active macromonomers generated need to be separated and purified to obtain active macromonomers; negative pressure dehydration is subject to reaction. Influenced by temperature and negative pressure, improper operation may easily cause a large amount of esterification raw materials to be extracted by boiling the pot, which will affect product quality.

Method used

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  • Preparation method of active large monomers by dehydration and esterification

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Feed according to the prescribed order, put methoxypolyethylene glycol and polymerization inhibitor hydroquinone into the reactor and stir for 5-10 minutes, then add methacrylic acid and stir for 3-5 minutes, then inhale the catalyst concentrated sulfuric acid, after the raw materials are fed Start to fill the reactor with nitrogen with a purity of 99.99%, and the filling rate in the first 2.5 hours is 3 to 4m 3 1 bottle of nitrogen gas per hour, the filling flow is 6~8m in the last 3 hours 3 3 bottles of nitrogen gas per hour, after nitrogen filling, heat preservation reaction for 0.5 hours, when the temperature drops below 50°C, add 30% liquid caustic soda with a mass of 0.2-0.5% of the total amount of all materials to neutralize the catalyst, and then mix the ingredients for the next polymerization process.

Embodiment 2

[0020] Put methoxypolyethylene glycol and polymerization inhibitor hydroquinone into the reaction kettle and stir for 5-10 minutes, then add methacrylic acid and stir for 3-5 minutes, then inhale the catalyst concentrated sulfuric acid, and keep the temperature at 120℃±2 After 1.5 hours of esterification reaction at ℃, fill the flow rate of 6~8m within 1 hour 3 / h 1 bottle of nitrogen with a purity of 99.99%, after 0.5 hours of heat preservation reaction, fill it with a flow rate of 6-8m within 2.5 hours 3 3 bottles of nitrogen gas per hour, and keep warm at 120°C±2°C for 0.5 hours. When the temperature drops below 50°C, add 30% liquid caustic soda with a mass of 0.2-0.5% of the total amount of all materials to neutralize the catalyst. The next polymerization process.

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Abstract

The invention relates to a preparation method of active large monomers by dehydration and esterification, comprising the steps of: putting methoxyl polyethylene glycol and a polymerization inhibitor (hydroquinone) into a reaction kettle and agitating for 5-10 minutes, then adding methacrylic acid and agitating for 3-5 minutes, absorbing a catalyst (concentrated sulfuric acid); after putting the raw materials, starting to fill nitrogen into the reaction kettle, wherein in the first 2.5 hours, one bottle of nitrogen with flow rate at 3-4 cubic meter / h is filled and in the last three hours, three bottles of nitrogen with flow rate 6-8 cubic meter / h are filled; performing insulating reaction for 0.5 hour after filling nitrogen, and adding caustic soda liquid in equilibrium amount to neutralize the catalyst after the temperature is reduced below 50 DEG C. Compared with prior art, the invention does not change the reaction temperature, and just fills nitrogen with different dosages in the esterification reaction kettle so that micromolecular water generated by the esterification reaction is removed to break the chemical balance so as to improve the esterification rate. The active large monomers synthesized by the method is used to synthesize a polycarboxylic acid water reducer with higher content of unsaturated bonds, high water reducing rate of concrete and small slump loss as well as excellent comprehensive performances and is stable in product quality.

Description

technical field [0001] The invention relates to the technical field of polymer synthesis, in particular to a preparation method for synthesizing active macromonomers through dehydration esterification. Background technique [0002] At present, esterification dehydration generally adopts solvent dehydration and negative pressure dehydration. Among them, solvent dehydration contains toxic solvents such as xylene or benzene, and the active macromonomers generated need to be separated and purified to obtain active macromonomers; negative pressure dehydration is subject to reaction. Influenced by temperature and negative pressure, improper operation may easily cause boiling of a large amount of esterification raw materials, which will affect product quality. Contents of the invention [0003] The technical problem mainly solved by the present invention is to provide a kind of preparation method of dehydration esterification synthesizing active macromonomer, the preparation meth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G65/00
Inventor 竹国斌丁联合
Owner 深圳市五山新材料股份有限公司
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