Oxidation of crotyl alcohol using Ti-β and Ti-MCM-41 catalysts

A comparative study of the oxidation of the crotyl alcohol using hydrogen peroxide and tert-butyl hydroperoxide as oxidants with TS-1,Ti-beta, Ti-Al beta, Ti-MCM-41, Ti-Al-MCM-41 and Ti-grafted-MCM-41 as catalysts is described and discussed. With hydrogen peroxide as oxidant, significant Ti-leaching is observed with all the catalysts except TS-I (Ti-Al beta > Ti-grafted-MCM-41 > Ti-MCM-41 > Ti beta >Ti-Al-MCM-41 much greater than TS-I). For Ti-Al beta, Ti-grafted- MCM-41 and Ti-Al-MCM-41, initial heterogeneously catalysed formation of the epoxide was observed. However, the formation of a Ti-species in solution is shown to contribute to competing homogeneously catalysed formation of ether diols and triol. Using tert-butyl hydroperoxide as oxidant the Ti-leaching was minimised and selective epoxide formation was observed with Ti-beta, Ti-Al beta and Ti-MCM-41 as heterogeneous catalysts, although, with Ti-Al beta, the ether diols and triol products dominated due to acid catalysed solvolysis of the epoxide. (C) 2001 Elsevier Science B.V. All rights reserved.