HETEROGENIZED POLYMETALLIC CATALYSTS .2. OXIDATION OF 3,5-DI-T-BUTYLPHENOL BY CU(II), FE(III) AND PD(II) COMPLEXED TO A POLYPHENYLENE POLYMER CONTAINING BETA-DIKETONE AND TRIKETONE SURFACE LIGANDS - AN IMPROVED CATALYST SYSTEM

Polyphenylene polymer preparation involves the cyclic trimerization po lymerization of acetylated methyl benzoate with diacetyl benzene. Sinc e the methyl benzoate groups do not take part in the polymerization th ey are present in high concentration. The P-diketone ligands were plac ed on the surface by reaction of the methylbenzoate group with base an d a methyl ketone and the triketone by reaction with base to give the beta-triketone. The beta-triketones can bind two metal ions in a known geometry that is suitable for bimetallic catalysis of the rapid polye lectron oxidation of catechols. The final catalytic surfaces were prep ared by treating the chemically modified polymer with copper(II), iron (II) and palladium(II) acetonitrile complexes with non-coordinating BF 4- as the anion. Since the metal ions contain no strongly coordinating ligand, they are very reactive species. These surfaces catalyzed the rapid air oxidation of 3,5-di-tert-butylcatechol (DTBC). The diketone surfaces gave only 3,5-di-tert-butyl-o-quinone (DTBQ) while the triket one surfaces gave ring-cleaved products, confirming the special cataly tic effect of the triketone surface. Also, only the triketone catalyst s showed any activity for ring cleavage oxidation of DTBQ. These catay lsts were much more reactive than previous ones using the same polyphe nylene polymer but without the methyl benzoate groups. With these poly mers the di- and triketone groups were placed on the surface by chemic al modification of the unpolymerized acetyl groups.