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

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-cyclohexen-1-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.

Graphical abstractHeterogeneous 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 efficient and selective for production of the corresponding epoxide.Figure optionsDownload full-size imageDownload as PowerPoint slide