Hydroformylation of Cyclohexene with Carbon Dioxide and Hydrogen Using Ruthenium Carbonyl Catalyst: Influence of Pressures of Gaseous Components

Hydroformylation of cyclohexene was studied with a catalyst system of Ru(3)(CO)(12) and LiCl using H(2) and CO(2) instead of CO in NMP. The influence of H(2) and CO(2) pressures on the total conversion and the product distribution was examined. It was shown that increasing total pressure of H(2) and CO(2) promoted the reverse water gas shift reaction and increased the yield of cyclohexanecarboxaldehyde. Its hydrogenation to cyclohexanemethanol was promoted with increasing H(2) pressure but suppressed with increasing CO(2) pressure. Cyclohexane was also formed along with those products and this direct hydrogenation was suppressed with increasing CO(2) pressure. The roles of CO(2) as a promoter as well as a reactant were further examined by phase behavior observations and high pressure FTIR measurements.