Selective liquid phase oxidation of secondary alcohols into ketones by tert-butyl hydroperoxide on nano-fibrous Ag-OMS-2 catalyst

Abstract

Selective oxidation of secondary alcohols to ketones using tert-butyl hydroperoxide was accomplished over active and reusable silver incorporated octahedral molecular sieve (Ag-OMS-2) catalyst. Different loadings of Ag (5–15% w/w) were incorporated in OMS-2 by the precipitation method among which 15% w/w Ag-OMS-2 was found to be the best. The catalyst was fully characterized. It possesses nanofibrous crystalline structure with high surface area. Oxidation of 1-phenylethanol, as a model compound, was conducted at 75 °C into acetophenone by tert-butyl hydroperoxide over 15% w/w Ag-OMS-2. Effects of various parameters were investigated in detail. A mathematical model is built to interpret the experimental data and develop mechanism. The reaction is intrinsically kinetically controlled and follows second order kinetics. The modeling will help reactor design and scale-up. As an extension to the studies, oxidation of various aliphatic and aromatic alcohols was studied in the liquid phase over 15% w/w Ag-OMS-2 catalyst under optimized conditions. The catalyst is reusable up-to five runs without any loss in catalytic activity. The results obtained are novel.