POLYMER-BOUND SUBSTRATES: A METHOD TO DISTINGUISH BETWEEN HOMOGENEOUS AND HETEROGENEOUS CATALYSIS.

Article abstract of DOI:10.1021/ja00321a014

Soluble and cross-linked polymers have been prepared and examined as substrates for hydrogenation reactions in the presence of homogeneous precatalysts, metal sols, and heterogeneous catalysts. These polymeric substrates are hydrogenated in the presence of soluble catalysts, whereas heterogeneous catalysts are ineffective. This phenomenon is proposed as a method to distinguish truly homogeneous from particulate catalysts. Using this test, the authors have found Crabtree's precatalyst, left bracket Ir(COD)L//2 right bracket PF//6, to behave as a homogeneous olefin hydrogenation catalyst. The Maitlis precatalyst, left bracket Rh(C//5Me//5)Cl//2 right bracket //2, acts as a homogeneous catalyst in the hydrogenation of olefins, but behaves like a heterogeneous catalyst in the hydrogenation of polymer-bound benzene derivatives.