SUBSTRATE SELECTIVITY OF HYDROCARBON OXIDATION BY THE (PDCL2-HETEROPOLY ACID) SIO2 SYSTEM AT 300-DEGREES-C/

The substrate selectivity of oxidation of hydrocarbons and other subst rates by the (PdCl2-HPA)/SiO2 system (HPA is heteropoly acid with the composition NanH9-n[PMo6V6O40] is Studied at the component ratio (mol) 0.3 : 0.7 : 100 and 300 degrees C. The relative rate constants, k(rel ) = k(RH)/k(C2H6), for various RH are found to be equal to: 0.14 (CH4) ; 0.06 (CD4); 2.0 (C3H8); 3.4 (n-C4H10); 7.2 (n-C5H12); 2.2 (iso-C4H10 ); 6.8 (cyclo-C5H10); 6.8 (cyclo-C6H12); 6.8 (cyclo-C6D12); 5.8 (CH3Cl ); 7.6 (CH3OH); 7.6 (CD3OD); and 15.0 (CH3OCH3). These values agree fa irly well with those obtained earlier for the (PdSO4-H2SO4)/SiO2 syste m at 220 degrees C and correlate well with the concept of C-H bond cle avage in saturated hydrocarbons under the action of palladium(II) acti vated by acids.