Highly selective catalytic epoxidation of cyclohexene and cyclooctene with r-butyl hydroperoxide by molybdenum(VI) compounds heterogenized in silica produced by the sol-gel process

摘要

Solid catalysts were obtained by the formation of silica matrixes in the presence of oxomolybdenum(Vi) complexes via the acid catalyzed hydrolytic sol-gel method using tetraethyl orthosilicate (TEOS). The obtained solids were tested as catalysts for the oxidation of cyclooctene and cyclohexene with t-butyl hydroperoxide. All performed reactions were selective for production of the corresponding epoxide, with formation of small traces of 2-cyclohexen-1-ol and 2-cydohexen-l-one (<2%). The best result was observed at 72-75 °C with a 91% yield of cyclohexen-oxide. No leaching of metal was observed and an increase on the catalytic activity was seen in recycle experiments.