RHODIUM COMPLEX CATALYZED HYDROFORMYLATION - RELATION BETWEEN EFFECTS OF CO PRESSURE AND PHOSPHINE CONCENTRATION

The hydroformylation of 1-hexene catalyzed by HRh(CO)(Pφ3)3 is performed at 25 °C and 1 atm total pressure without the use of solvent. A narrow range of CO pressure and phosphine concentration is identified, in which high activity and regioselectivity for linear aldehyde formation is boserved. This is not the result of a suppression of the branched aldehyde formation, but is caused by increased activity for production of the linear isomer. The observations are discussed in relation to previously suggested mechanisms, and the possibility of the square trans phosphine, HRh(CO)(Pφ3)2, being responsible for this high activity and regioselectivity is considered. © 1979.