Influence of TS-1 structural properties and operation conditions on benzene catalytic oxidation with H2O2

The preparation method described by Thangaraj et al. was used to obtain samples of titanium-silicalite (TS-1) for the catalytic hydroxylation of benzene with hydrogen peroxide. These samples were characterized by X-ray diffraction, scanning electron microscopy, skeletal infra-red spectroscopy and ultraviolet-visible diffuse reflectance spectroscopy (UV-VIS DRS). Pure TS-1 (without extra-framework titanium) with a maximum Ti/Si ratio of 0.020 was obtained. UV-VIS DRS measurements allowed us to infer the existence of different Ti4+ sites in the TS-1 framework. Small changes in the preparation conditions lead to the presence of extra-framework titanium. The influence of extraframework titanium, traces of sodium and the operation conditions (such as the method of H2O2 addition and the presence of a solvent on TS-1 activity and selectivity to phenol) were analyzed. (C) 1998 Elsevier Science B.V. All rights reserved.