1435-71-8Relevant articles and documents
Continuous preparation method of 2-nitro-2'-hydroxy-5'-methyl azobenzene
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Paragraph 0018-0022, (2021/06/21)
The invention discloses a preparation method of 2-nitro-2'-hydroxy-5'-methyl azobenzene. According to the continuous preparation method, o-nitroaniline/sodium nitrite/acid/p-cresol is taken as a raw material, a micro-channel reactor is connected in series with a rotary liquid membrane reactor, and the reaction temperature, the reaction time and the like are accurately controlled, so that an azo intermediate 2-nitro-2'-hydroxy-5'-methyl azobenzene is prepared with high conversion rate and high selectivity. The method has the advantages of being simple in process, high in production efficiency, safe, environmentally friendly and easy to industrialize.
Synthesis of new ultraviolet light absorbers based on 2-aryl-2H- benzotriazoles
Koutsimpelis, Aristides G.,Screttas, Constantinos G.,Igglessi-Markopoulou, Olga
, p. 1393 - 1401 (2007/10/03)
A procedure for the synthesis of some new ultraviolet absorbers of the benzotriazole series is reported. The compounds bear a carboxylic or a formyl group para to the hydroxy group, and these functionalities impart to the absorbers improved compatibility with certain disperse dyes on polyester fibers.
Processes for the preparation of benzotriazole UV absorbers
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, (2008/06/13)
Provided is a process for preparing 2H-benzotriazole UV absorbers containing a perfluoroalkyl moiety at the 5-position of the benzo ring, for example a trifluoromethyl group, which involves diazotizing the perfluoroalkyl substituted o-nitroaniline using concentrated sulfuric acid plus sodium nitrite or nitrosylsulfuric acid to form the corresponding monoazobenzene intermediate via the diazonium salt intermediate which is reduced to the corresponding 5-perfluoroalkyl substituted 2H-benzotriazole UV absorber compound by conventional reduction means. Also provided is a novel one-pot, multiphase reaction for the preparation of 2(2-nitrophenylazo) substituted phenols, which are precursors for 2H-benzotriazole UV absorbers.