Preparation of benzotrizole light stabilizer

Abstract

A process for preparing the benzotriazole as photostabilizer includes such steps as dissolving 2-nitro-2'-hydroxy-5'-methyl azobenzene and 2-nitro-2'-hydroxy-3'- tert-butyl-5'-methyl propionate azobenzene in the mixture of alcohol and alkali solution, adding hydrazine hydrate, heating, reflux reaction, using hydrochloric acid to neutralize the reaction liquid, depositing, filtering, water washing, drying to obtain an intermediate, dissolving it in the mixture of alcohol and alkali, adding sodium dithionate, stirring while reacting, adding ice water, neutralizing, filtering, drying, and recrystallizing in alcohol or isopropanol.

Description

technical field The invention relates to a preparation method of a benzotriazole light stabilizer, which belongs to the light stabilizer technology. Background technique Benzotriazole light stabilizer structural formula is shown in formula (I): In formula (I), R is -H, -Cl or -Br; R 1 for -H, C 1 -C 12 Alkyl, C 1 -C 4 Alkoxyphenyl, -Cl, (C 1 -C 8 Alkyl) phenyl, C 5 -C 6 Cycloalkyl, C 2 -C 9 Alkoxyacyl, carboxyethyl or C 7 -C 9 Phenylalkyl; R 2 for -H, C 1 -C 12 Alkyl, -Cl, C 5 -C 6 Alkoxy, C 7 -C 9 Phenylalkyl or -C n h 2n -COOCH 3 (n is 0, 1, 2, 3, 4). Benzotriazole light stabilizer is a kind of polymer synthetic material additive, which is widely used in organic polymers such as plastics, synthetic rubber, synthetic fibers, dyes, paints and pigments, to prevent them from aging under ultraviolet radiation and prolong their durability. service life. In addition, it can also be added to cosmetics to prevent the radia...

AI Technical Summary

Problems solved by technology

This method needs to handle a large amount of zinc compounds and lye after the reaction owing to having used excessive zinc powder and lye, and this process step is loaded down with trivial details, and the cycle of reaction is long, pollutes environment