Catalytic carbon monoxide hydrogenation with dodecacarbonyltriosmium and boron tribromide

Abstract

The catalytic hydrogenation of carbon monoxide with Os/sub 3/(CO)/sub 12/ as a catalyst precursor and boron tribromide as a solvent, catalyst promoter, and ultimate reactant is described. Reaction conditions were relatively mild: 180/sup 0/C and approx. 2 atm. The hydrogenation products were unique and included methane, ethane, propane, isobutane, neopentane, methyl bromide, ethyl bromide, propyl bromides, and butyl bromides. The major products were methyl and ethyl bromides. During the course of the catalytic reaction Os/sub 3/(CO)/sub 12/ was converted to Os/sub 2/(CO)/sub 6/Br/sub 4/. The latter was shown to function as a catalyst precursor to produce a similar range of hydrocarbon and alkyl bromide products. Substitution of BCl/sub 3/ for BBr/sub 3/ gave an analogous reaction system. Conversion of Os/sub 3/(CO)/sub 12/ to Os/sub 3/(CO)/sub 10/Cl/sub 2/ and Os/sub 2/(CO)/sub 6/Cl/sub 4/ was established for the CO hydrogenation system. The BCl/sub 3/ reaction system was, however, sharply differentiated from the BBr/sub 3/ system in that only hydrocarbons were produced; no alkyl chloride products were detected.