Heteropolymolybdoacids, H-3[PMo12O40] and H-6[P2Mo18O62], catalyze the oxidative cleavage of C-Sn bond in the organotin derivatives of dibenzyldichlorotin (1) and tribenzylchlorotin (2) in the presence of dioxygen. Benzaldehyde is the major reaction product, accompanied by smaller amounts of benzyl alcohol, benzyl chloride and dibenzyl. The results show that H-6[P2Mo18O62] as catalyst and ethanol (as solvent) produce the highest yield of benzaldehyde at 65 degreesC. Also, I produces a higher yield than 2. The effects of catalyst type, temperature and solvent on the reaction time have been examined. In every case, H-6[P2Mo18O62] causes the C-Sn bond cleavage to be achieved in a shorter time than does H-3[PMo12O40]. (C) 2003 Elsevier B.V. All rights reserved.