CATALYTIC-SYSTEMS BASED ON TRANSITION-METALS FOR THE CARBONYLATION OFMETHANOL TO DIMETHYLCARBONATE

The results of an investigation on catalytic systems arising from the electrochemical activation of salts and complexes of several transitio n metals for the carbonylation of methanol to dimethylcarbonate (DMC) are reported. Metals were tested as inorganic salts or complexes with ligands such as 2,2'-bipyridine (bipy), 1,6-bis (2-oxyphenyl)-2,5-diaz a-1,5-hexadiene (salen), 2,4-pentanedionate (acac), triphenylphosphine (TPP) in methanol at room temperature saturated with carbon monoxide at atmospheric pressure. Best faradic yields vs DMC were observed as f ollows: CuCl(bipy): 84.8%; PdCl2(bipy): 64.0%; CoCl2: 26.0%; RhCl3: 25 .0%; AgBF4(bipy): 10.2%; AuCl3: 9.4%; Cr(acac)(3): 6.7%; PtCl2(bipy): 2.1%; NiCl2: 1.8%. The influence of the ligand on faradic yields has b een also investigated. (C) 1997 Elsevier Science Ltd.