LARGE-PORE TI-ZEOLITES AND MESOPOROUS TI-SILICALITES AS CATALYSTS FORSELECTIVE OXIDATION OF ORGANIC SULFIDES

The oxidation of bulky thioethers has been carried out on Ti-Beta and Ti-MCM-41 catalysts, using H2O2 and t-butyl hydroperoxide (TBHP) as ox idants. The intrinsic activity of Ti-Beta was higher than that of Ti-M CM-41 for the oxidation of methyl phenyl sulfide which can penetrate i n the pores of Beta, while in the case of the larger isopentyl phenyl sulfide, which diffuses more slowly in Ti-Beta zeolite, Ti-MCM-41 give s a larger activity. Ti-Beta is able to perform better for the more de manding oxidation of sulfoxides to sulfones giving, therefore, higher selectivities to sulfones than Ti-MCM-41. Similar results were obtaine d when using either H2O2 or TBHP as oxidants. However, the sterical ef fects were enhanced when TBHP was used as oxidant.