Catalytic activity and stability of a chromium containing silicate in liquid phase cyclohexane oxidation

A chromium containing silicate has been prepared by an acid-catalyzed sol-gel process. The material was characterized by FTIR, W-VIS and EPR spectroscopy as well as TPR, XRD and XRF analyses. The silicate is an efficient catalyst for the oxidation of cyclohexane with tert-butyl hydroperoxide. Leaching studies showed that catalysis is at least in part due to traces of Cr leached into the homogeneous phase. Weakly bound Cr species can be removed by soxhlet extraction, yielding a catalyst which is remarkably leaching resistant. The catalyst can be used at least four times without detectable loss of metal. (C) 2001 Elsevier Science B.V. All rights reserved.