Hydroformylation with Cobalt Carbonyl and Cobalt Carbonyl-Tributylphosphine Catalysts

Abstract

By in situ ir spectroscopic techniques it was found that the cobalt carbonyl catalyst in hexane, after preforming at conditions of hydroformylation (temperatures of 101 and 124OC, Pc0 = 11 and 30 bars, PH2 = 20 and 49 bars, cobalt concentration = 2.0 and 4.2 mmolll.) consisted of more than 80% HCO(CO)~, the rest being C02(C0)8. Injection of octene-I, in order to start the hydroformylation, caused HCO(CO)~ to decrease (although not to zero concentration) in favor of an increasing CO~(CO)~ concentration. This reverted as the conversion of octene-1 increased. As intermediate complexes, only acyl cobalt carbonyl species were detected in very low concentrations. A catalyst composed of cobalt carbonyl and tributylphosphine in a phosphorus-to-cobalt ratio of 5, of a considerable amount of catalytically inactive CO~(CO),PBU~, while of all hydridocobalt carbonyls present only a minor part was liganded by PBu3 at the previously mentioned reaction conditions. Accordingly, in the hydroformylation of octene-I, the catalyst decreased only the octene conversion rate and left the yield of unbranched products unaffected.

Kinetic Studies on the Cobalt-Catalyzed Norbornadiene Intermolecular Pauson−Khand Reaction

“…A feasible explanation could be that a dimerization process occurs to a certain degree in the reaction. Cobalt carbonyl complexes are postulated to be involved in higher order bimolecular reaction mechanisms, as in the case of cobalt-catalyzed hydroformylation . The Co 2 (CO) 8 complex dimerizes to afford the Co 4 (CO) 12 cluster ( 6 ) under thermal activation .…”

Rhodium carbonyl cluster chemistry under high pressure of carbon monoxide and hydrogen. 3. Synthesis, characterization, and reactivity of HRh(CO)4

“…The infrared pattern is consistent with those previously reported for the bridging form of Rh2(CO)8. [15][16][17][18][19]34 The variation of the relative amounts of Rh4(CO)12 and Rh2(CO)8 with temperature and pressure of carbon monoxide as observed by us upon gradual variation (34) R. L. Sweany and T. L. Brown, Inorg. Chem., 16, 415 (1977).…”

An analysis of mass-transfer effects in hydroformylation reactions

“…This analysis should be applicable to hydroformylation and other reactions that follow similar rate model. Such an analysis is essential since hydroformylation reactions are known to be operating under conditions of significant mass-transfer limitation (Van Boven et al, 1975). Certain interesting practical implications of this analysis have been discussed with hydroformylation of 1-hexene as an illustrative example.…”