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Preparation method of 2,2'-(4,4'-distylyl) dibenzoxazole by adopting new sulphur method

A technology of stilbene and methylbenzoxazole, which is applied in the preparation of fluorescent whitening agents, 2 fields, can solve the problems of large amount of sulfur and large reaction energy consumption, and achieves reduction in energy consumption, improvement in use performance, Bright product appearance

Active Publication Date: 2013-08-28
HUBEI HONGXIN CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is exactly in order to solve the problem that prior art occurs, provide a kind of new sulfur method 2,2'-(4,4'-distyryl) bisbenzoxazole preparation method, in 4-methylbenzene In the oxidative condensation reaction of oxazole, an aprotic organic solvent is used instead of sulfur as the reaction medium, and only the amount of sulfur used as an oxidant is added, and the reaction temperature drops to 190-230°C. Due to the solvation effect, the reaction yield increases to 80%. The above, and effectively solve the problems of excessive sulfur consumption and excessive reaction energy consumption.

Method used

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  • Preparation method of 2,2'-(4,4'-distylyl) dibenzoxazole by adopting new sulphur method

Examples

Experimental program
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Effect test

Embodiment 1

[0025] Example 1 Dissolve toluic acid and o-aminophenol in solvent oil in a reaction kettle, use boric acid as a catalyst, pass nitrogen gas, heat up to 140-160°C for dehydration condensation, and generate 4-methylbenzoxane as a raw material azole;

[0026] Drop into 4-methylbenzoxazole 300kg and sulfur 46kg in vulcanization reactor, its consumption is that 4-methylbenzoxazole molar weight is equal, and its consumption is that 4-methylbenzoxazole molar weight is equal, then Add 1000L guide oil, heat, raise the temperature to 170°C, start stirring, continue to heat up to 215-220°C to react, open the hydrogen sulfide trap, the generated hydrogen sulfide is discharged to the absorption tower with lye through the trap Absorbed, after about 3 hours, the reaction was completed, cooled, filtered, and 245kg of crude fluorescent whitening agent OB-1 was obtained;

[0027] The crude fluorescent whitening agent OB-1 was washed with xylene and recrystallized from trichlorobenzene to obta...

Embodiment 2

[0028] Example 2, dissolve toluic acid and o-aminophenol in solvent oil in a reaction kettle, use boric acid as a catalyst, pass nitrogen gas, heat up to 140-160°C for dehydration condensation, and generate 4-methylbenzo as raw material Oxazole;

[0029] Drop into 4-methylbenzoxazole 300kg and sulfur 46kg in vulcanization reactor, its consumption is that 4-methylbenzoxazole molar weight is equal, and its consumption is that 4-methylbenzoxazole molar weight is equal, then Add 1000L hexamethylphosphoric triamide, heat, raise the temperature to 170°C, start stirring, continue to heat up to 200-205°C to react, open the hydrogen sulfide trap, the generated hydrogen sulfide is discharged through the trap to the The absorption tower is absorbed, and after about 4 hours, the reaction is finished, cooled, and filtered to obtain 256kg of fluorescent whitening agent OB-1 crude product;

[0030] The crude fluorescent whitening agent OB-1 was washed with xylene and recrystallized from tri...

Embodiment 3

[0031] Example 3, dissolve toluic acid and o-aminophenol in solvent oil in a reaction kettle, use boric acid as a catalyst, pass nitrogen gas, heat up to 140-160°C for dehydration condensation, and generate 4-methylbenzo as raw material Oxazole;

[0032] Drop into 4-methylbenzoxazole 300kg and sulfur 46kg in vulcanization reactor, its consumption is that 4-methylbenzoxazole molar weight is equal, and its consumption is that 4-methylbenzoxazole molar weight is equal, then Add 1000L formamide, heat, raise the temperature to 170°C, start stirring, continue to heat up to 190-195°C to react, open the hydrogen sulfide trap, and the generated hydrogen sulfide is discharged through the trap to the absorption tower with lye for absorption , after about 4 hours, the reaction was finished, cooled, and filtered to obtain 255kg of the crude product of fluorescent whitening agent OB-1;

[0033] The crude fluorescent whitening agent OB-1 was washed with xylene and recrystallized from trichl...

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Abstract

The invention relates to a preparation method of 2,2'-(4,4'-distylyl) dibenzoxazole by adopting a new sulphur method. The preparation method is characterized in that methyl benzoic acid and ortho-aminophenol are dissolved in solvent oil, and boric acid is taken as a catalyst, so as to generate 4-methyl benzoxazole taken as a raw material; in an oxidation condensation reaction process of 4-methyl benzoxazole, an aprotic organic solvent is adopted for replacing sulphur as a reaction medium, wherein the aprotic organic solvent is diphenyl ether, hexamethylphosphoric triamide or formamide, a reaction temperature is 190-230 DEG C, reaction time is controlled to be 3-4 hours, energy consumption is reduced, and reaction yield and product quality are improved as the salvation effect and using amount of sulphur are reduced; and besides, equipment investment is reduced, and solid waste is greatly reduced, so that the preparation method is a clean production technology. A fluorescent brightener OB-1 provided by the invention can be used in ingredients of plastics, chemical fibers and the like for whitening and brightening.

Description

technical field [0001] The invention belongs to the field of preparation of chemical raw materials, in particular to a preparation method of a fluorescent whitening agent, in particular to a 2,2'-(4,4'-distyryl)bisbenzoxazole Preparation. Background technique [0002] Fluorescent whitening agent OB-1, the chemical name is 2,2'-(4,4'-distyryl)bisbenzoxazole, which belongs to benzoxazole dispersed fluorescent whitening agent, it can absorb ultraviolet rays Then emit blue-violet fluorescence, which is superimposed with the yellow light emitted by the substrate that needs to be whitened to form white light, so that the product obtains white light, and at the same time increases the brightness of the product. It has stable performance, good high temperature resistance, and light resistance. , Chlorine bleaching resistance and migration resistance, it is widely used in whitening and brightening in plastics, chemical fiber, coatings and other industries. It is a high-grade ...

Claims

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Application Information

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IPC IPC(8): C07D263/57
Inventor 寇志成杨玉忠
Owner HUBEI HONGXIN CHEM CO LTD
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