Synthesis of condensation polymers catalyzed by palladium-graphite

Abstract

Palladium-graphite (PdGr) was applied to polycondensations as a heterogeneous palladium catalyst. Catalytic activities of PdGr for the Heck reaction and a carbonyl insertion reaction were investigated using the model reactions. Polycinnamamide was synthesized through the Heck reaction of N, N′-(3,4′-oxydiphenylene)bis(acrylamide) and bis(4-iodophenyl) ether catalyzed by PdGr. The polymerization proceeded efficiently in the presence of tributylamine, but required a long reaction time compared with the case of homogeneous catalysts. The resulting polymer was almost white in color, which means that it was less contaminated by palladium metal. The removal and recycling of PdGr were much easier than the case of homogeneous catalysts. Aramid was also synthesized through the carbonyl insertion reaction of m-diiodobenzene and bis(4-aminophenyl) ether catalyzed by PdGr. The rate of carbon monoxide consumption for the polymerization catalyzed by PdGr was almost equal to that catalyzed by the homogeneous palladium catalyst. In both cases, the structures of the resulting polymers were identical to those prepared by homogeneous palladium catalysts.