OXIDATION OF ALCOHOLS WITH H2O2 CATALYZED BY TITANIUM SILICALITE-1

Primary and secondary alcohols are oxidised by H2O2 in the presence of titanium silicalite-1 to carbonylic compounds. Reaction rates follow the general trend secondary > primary > methanol. Rates are sensitive to position effects of the OH group, to chain branching effects, and t o molecular size of the alcohol. Kinetic orders with respect to H2O2 a re generally close to zero, while those with respect to the alcohol ar e strongly affected by the solvent used. The kinetic pattern is interp reted in terms of an interaction of the lattice titanium atom of titan ium silicalite-1 with H2O2. The kinetic order with respect to the alco hol can be interpreted either in terms of titanium-alcohol adducts or with a selective alcohol sorption in the catalyst pores. The reaction pattern is consistent with a process taking place essentially inside t he zeolite channels, with a transition-state-restricted shape-selectiv ity. The nature of the titanium hydroperoxide involved in the intermed iate complex is discussed. (C) 1994 Academic Press, Inc.