Toluene → UV-328

Participants

Reaction Steps

38.39 g (0.1 mol) of 2-nitro-2'-hydroxy-3',5'-di-t-amylazobenzene, 5 g of Raney nickel, 100 ml of toluene, 100 ml of isopropyl alcohol (referred to as "IPA" hereinafter) 100 ml of water and 8 g (0.2 mol) of caustic soda were charged into a 500-ml stainless autoclave with an agitator. After the air in the flask had been replaced by hydrogen, the pressure of hydrogen was set to 10 kg/cm2. The temperature was increased at a rate of 20° to 40° C./hour and then 40° to 50° C./hour while the resultant mixture being agitated. Reaction was then effected at 50° to 90° C. for 2 hours and then 90° C. for 7 hours and was stopped when no more hydrogen was absorbed by the reaction solution. The autoclave was cooled, and the catalyst was filtered off. After the filtrate had been allowed to stand, the toluene layer was separated, and most part of the toluene was distilled off. The residual solid obtained was crystallized by IPA and the dried to obtain 28.8 g of 2-(2'-hydroxy-3',5'-di-t-amylphenyl)benzotriazole (yield, 82%; melting point, 79° to 80° C.).

Provenance & Evidence