HETEROGENIZED POLYMETALLIC CATALYSTS .3. CATALYTIC AIR OXIDATION OF ALCOHOLS BY PD(II) COMPLEXED TO A POLYPHENYLENE POLYMER CONTAINING BETA-DI-KETONE AND TRI-KETONE SURFACE LIGANDS

This paper describes further studies on mono- and bi-metallic catalyst s attached to a polymer support by beta-di- and tri-ketone surface Lig ands. The previous two papers described the oxidation of catechol by t he heterogeneous catalysts using Cu(II), Fe(III) and Pd(II) as the met al species, The present study expands these studies to a series of mon o- and polyfunctional alcohols using Pd(II) as the metal species. The final catalytic surfaces were prepared by treatment of the modified po lymer with a very reactive form of Pd(II), [Pd(CH3CN)(4)](2+). The sim ple alcohols gave increases in rates of up to 5-fold for the bimetalli c systems. As might be expected glycols and alpha-D-glucose gave even higher increases in rate in going from the mono- to the bi-metallic ca talyst. For ethylene glycol the factor was 30. Unsaturated alcohols ga ve the most dramatic results, With the monometallic catalyst, the prod ucts from allyl alcohol consisted of 25% acrolein resulting from direc t alcohol oxidation and 75% 3-hydroxypropanal resulting from Wacker-ty pe oxidation of the double bond. With the bimetallic catalyst the over all rate increased by a factor of 10 and the products consisted of 80% acrolein and 20% 3-hydroxypropanal, The actual rate increase for the direct alcohol oxidation is calculated to be a factor of 32. 4-Penten- 2-ol and 4-penten-1-ol gave rates that were lower than the monofunctio nal alcohols. This is attributed to inhibition by olefin pi-complex fo rmation with the Pd(II).