Hydrocarbonylation of ethyl orthoformate in the presence of rhodium catalysts

Article abstract of DOI:10.1016/0022-328X(88)83093-6

The reaction of ethyl orthoformate with a mixture of CO and H2 (P 8 MPa) in the presence of various rhodium carbonyl catalysts with and without iodide promoters at temperatures of 150-170 deg C has been studied.The ^-/CH3I systems mainly catalyze the hydrogenation of ethyl orthoformate to diethoxymethane without any subsequent hydrogenation to methyl derivatives and methane.Carbonylation and hydrocarbonylation products of the ethyl moiety, i.e. ethyl propionate and 1,1-diethoxypropane together with diethyl carbonate coming from carbonylation of the ethoxy group, are produced, with a maximum selectivity of 12percent.Chlorocarbonylrhodium systems without iodide promoters are active in the hydrogenation and hydrocarbonylation of the substrate, whereas carbonylrhodium derivatives without halide ligands and promoters only catalyze the hydrogenation to diethoxymethane.IR spectroscopic studies show that the rhodium species produced under the reaction conditions are in all cases anionic halocarbonyl or carbonyl complexes, and the course of the reaction seems to depend on the hydrido character of the parent derivative.