Highly selective synthesis of enones from benzylic compounds over CrSBA-15

Mesoporous CrSBA-15 catalysts synthesized with a variety of nSi/nCr ratios by pH-aDH method were used in the production of enones by the liquid-phase oxidation of benzylic compounds. To investigate the leaching of chromium species on the silica surface, CrSBA-15(8) was chemically treated with ammonium acetate solution while the Cr-containing mesoporous silica catalysts used for these reactions were regenerated by washing and calcinations. The treated catalysts such as washed CrSBA-15 and regenerated CrSBA-15 catalyst were used/reused in these reactions to find their catalytic activities. Furthermore, the influences of various reaction parameters such as temperature, time, ratios of reactant and solvents on the synthesis of tetraline (Tdouble bond; length as m-dashO) have been systematically investigated. Based on the catalytic investigations, CrSBA-15(8) catalyst is found to be a highly active, recyclable and promising heterogeneous catalyst for the selective synthesis of enones, and it has superior catalytic activity in the oxidation of benzylic compounds than CrMCM-41.