HYDROFORMYLATION OF OLEFINS CATALYZED BY RHODIUM AND COBALT CLUSTERS SUPPORTED ON ORGANIC (DOWEX) RESINS

Co2Rh2(CO)12 or a mixture of Co4(CO)12 and Rh4(CO)12 were impregnated onto organic Dowex(R) resins to study the hydroformylation of olefins. Pressure, reaction time and amount of catalysis effect the alcohol production and the ratio of straight chain to branched alcohols in the Co2Rh2(CO)12-Dowex amine resin catalytic system. 50 bar of synthesis gas pressure, 17 h total reaction time and 0.050 g catalyst were the optimum conditions in the hydroformylation of 1-hexene at 100-degrees-C, where the maximum yield of alcohols is 95%. Other hexene isomers and different olefins were studied as hydroformylation substrates. The presence of amine groups on the support or the addition of Et3N to the hydroformylation solution is necessary for the single-step alcohol formation. This conclusion was deduced from studies of the supports with a similar matrix but different functional groups. The mixture of Co4(CO)12 and Rh4(CO)12 supported on organic amine Dowex resin is an excellent catalyst, giving 99% alcohol production. The ratio of Rh/Co has a marked effect on the product distribution. The best alcohol conversions are reached with 2.6 or 3.6 of Rh/Co weight ratio. Co2Rh2(CO)12 decomposes to give a known, but not optimum, composition of Co and Rh on the support. Therefore a mixture of Co4(CO)12 and Rh4(CO)12 is a better catalyst precursor than Co2Rh2(CO)12.