Method for preparing polymerization inhibitor (4-benzoyl-2,2,6,6-tetramethylpiperidine-1-nitroxide free radical)

A tetramethylpiperidine, nitroxide free radical technology, applied in chemical instruments and methods, physical/chemical process catalysts, organic compounds/hydrides/coordination complex catalysts, etc., can solve the problem of easy hydrolysis, product yield lower problem

Inactive Publication Date: 2011-01-19
南通惠康国际企业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the magnesium methoxide and tetrabutyl titanate catalysts are easily hydrolyzed by water, the Ph value of the system is increased, which has adverse effects on the transesterification reaction, and the product yield is low.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] In a four-necked reaction flask equipped with an electric stirrer, reflux condenser and thermometer, add 27.7g of 4-benzoyl-2,2,6,6-tetramethylpiperidine, 28.3g of hydrogen peroxide, and 1g in sequence Install the reflux condenser, thermometer, start the stirrer, start timing when the temperature reaches 50-65℃, and the reaction time is 10h (use gas chromatography to monitor the reaction). After the reaction is over, add petroleum ether with a boiling range of 60-90℃, stir and stand still, let the lower aqueous solution clean, and then reflux and separate the water, cool, crystallize, and filter to obtain orange-red 4-benzoyl-2 ,2,6,6-Tetramethylpiperidine-1-nitroxide free radical product. The yield reached 91.63%, and the melting point was 104-105°C.

Embodiment 2

[0017] In a four-necked reaction flask equipped with an electric stirrer, a reflux condenser and a thermometer, add 27.7g of 4-benzoyl-2,2,6,6-tetramethylpiperidine, 39.7g of hydrogen peroxide, and 1g in sequence. Install the reflux condenser, thermometer, start the stirrer, start timing when the temperature reaches 50-65℃, and the reaction time is 10h (use gas chromatography to monitor the reaction). After the reaction is over, add petroleum ether with a boiling range of 60-90℃, stir and stand still, let the lower aqueous solution clean, and then reflux and separate the water, cool, crystallize, and filter to obtain orange-red 4-benzoyl-2 ,2,6,6-Tetramethylpiperidine-1-nitroxide free radical product. The yield reached 91.95%, and the melting point was 104-105°C.

Embodiment 3

[0019] In a four-necked reaction flask equipped with an electric stirrer, reflux condenser and thermometer, add 27.7g of 4-benzoyl-2,2,6,6-tetramethylpiperidine, 28.3g of hydrogen peroxide, 1.5 g of composite catalyst, install reflux condenser, thermometer, start the stirrer, start timing when the temperature reaches 50-65°C, reaction time 10h (use gas chromatography to monitor the reaction). After the reaction is over, add petroleum ether with a boiling range of 60-90℃, stir and stand still, let the lower aqueous solution clean, and then reflux and separate the water, cool, crystallize, and filter to obtain orange-red 4-benzoyl-2 ,2,6,6-Tetramethylpiperidine-1-nitroxide free radical product. The yield reached 92.01%, and the melting point was 104-105°C.

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Abstract

The invention discloses a method for preparing a polymerization inhibitor (4-benzoyl-2,2,6,6-tetramethylpiperidine-1-nitroxide free radical). 4-benzoyl-2,2,6,6-tetramethylpiperidine and hydrogen peroxide are used as raw materials and reacted in the presence of a composite catalyst to obtain the 4-benzoyl-2,2,6,6-tetramethylpiperidine-1-nitroxide free radical. The method for synthesizing the 4-benzoyl-2,2,6,6-tetramethylpiperidine-1-nitroxide free radical by adopting the composite catalyst simplifies the separation and purification processes, has the advantages of short reaction time, high product yield which reaches over 91 percent of product yield, high product purity, low energy consumption, low environmental pollution and low cost, and is an ideal process for realizing industrialized production.

Description

technical field [0001] The invention relates to a preparation method of a polymerization inhibitor (4-benzoyl-2,2,6,6-tetramethylpiperidine-1-nitroxyl radical). Background technique [0002] 4-Benzoyl-2,2,6,6-tetramethylpiperidine-1-nitroxyl radical is a new type of stable free radical discovered recently. The excellent polymerization performance has made its application in the production process of unsaturated monomer compounds develop rapidly in recent years, so it is of great practical significance to replace traditional phenolic polymerization inhibitors with hindered amine nitrogen nitrogen oxide free radical compounds. It can be applied to the prevention of polymerization fouling of low-carbon olefins, and can also be applied to compounds such as acrylates, methacrylates and acrylic acid. Its polymerization inhibition performance is better than that of hydroquinone, hydroquinone monomethyl ether, phenothiazine and di Polymerization inhibition effect of copper butyl di...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D211/98B01J31/34
Inventor 王树清孙冬兵缪小勇
Owner 南通惠康国际企业有限公司
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