NEW ASPECTS OF THE SYNTHESIS OF DIMETHYL CARBONATE VIA CARBONYLATION OF METHYL-ALCOHOL PROMOTED BY METHOXYCARBONYL COMPLEXES OF PALLADIUM(II)

[PdCl2(PPh3)2] suspended in MeOH reacts with carbon monoxide (40-80 atm, 50-degrees-C), in the presence of a base such as NEt3 to give the methoxycarbonyl complex trans-[PdCl(COOMeXPPh3)2]. When the carbonylation reaction is carried out at 90-100-degrees-C reduction to Pd0 carbonyl-phosphine complexes occurs, with formation of dimethyl carbonate, selectively and in an almost quantitative yield. The above complexes are less reactive than the acetato-analogues, which give dimethyl oxalate as the main organic carbonylation product even at 50-degrees-C.