Producing technology of benzotriazole-typed ultraviolet absorber

Abstract

The invention belongs to the field of a producing technology of an ultraviolet absorber and discloses a producing technology of a benzotriazole-typed ultraviolet absorber. The producing technology includes following steps: mixing ortho-nitroaniline, concentrated hydrochloric acid and water with stirring to obtain a mixed solution; heating the mixed solution to 75 DEG C and cooling the mixed solution to 0 DEG C; adding a solution prepared from sodium nitrite and water to the mixed solution and mixing and stirring the solution with the mixed solution; adding sulfamic acid to obtain a diazonium solution; carrying out a coupling reaction to the diazonium solution with 2,4-dicumenylphenol in an alkaline methanol solution; directly adding hydrazine hydrate after the coupling reaction finished for performing a primary reduction reaction; adding methylbenzene after the primary reduction reaction finished; separating a methanol water phase and recycling methanol through rectification; washing the balanced solvent layer through hot water and heating the solvent layer to 60-65 DEG C; performing an acidizing operation with addition of concentrated hydrochloric acid; adding zinc powder for carrying out a secondary reduction reaction; and adding methanol and performing crystallization to separate out the benzotriazole-typed ultraviolet absorber. The producing technology can effectively shortened technology processes. Purity of an intermediate is improved after extraction. The benzotriazole-typed ultraviolet absorber is reduced in cost.

Description

technical field [0001] The invention belongs to the technical field of production of ultraviolet absorbers, in particular to a production process of benzotriazole ultraviolet absorbers Background technique [0002] Benzotriazole is an organic compound, also known as benzotriazole, benzotriazole, etc. It is a white to light pink needle crystal, soluble in benzene and toluene. Benzotriazole is a good ultraviolet light absorber and can be used as a developing anti-fogging agent for black and white film and photographic paper. [0003] At present, for the synthesis of benzotriazole ultraviolet absorbers, the mature production processes at home and abroad are all through diazo, coupling, and reduction closed-loop approaches, and they are all synthesized by means of separation and purification of intermediate products. In the production process, because there is an intermediate centrifuge In the output link, the labor intensity of the employees is high, the operating environment ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a production process of benzotriazole ultraviolet absorbers. Through technical improvement, process steps such as centrifugal extraction of intermediates and neutralization with inorganic acids are omitted, and the coupling is completed. There is no need to use inorganic acid for neutralization and direct reduction, which simplifies the production process and solves the problems of high labor intensity, poor operating environment, and possible secondary pollution of the product.

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