Olefin hydrogenation, supercritical carbon dioxide

Catalytic Hydrogenation of Olefins in Supercritical Carbon Dioxide Using Rhodium Catalysts Supported on Fluoroacrylate Copolymers... 

The hydrogenation of olefins in supercritical carbon dioxide catalyzed by palladium nanoparticles synthesized in a water-in-C02 microemulsion was reported by Ohde et al (27). The Pd nanoparticles were prepared by hydrogen reduction of Pd ions (a PdCl2 solution) dissolved in the water core of the microemulsion. Effective hydrogenation of both C02-soluble olefins (4-methoxycinnamic acid and trans-stilbene) and a water-soluble olefin (maleic acid) catalyzed by the palladium nanoparticles in the microemulsion was demonstrated. 

P. G. Jessop, T. Ikariya, R. Noyori, Selectivity for Hydrogenation or Hydroformylation of Olefins by Hydrido-pentacarbonylmanganese(I) in Supercritical Carbon Dioxide , Organometallics 1995,14,1510-1513. 

Bianchini, C. Glendenning, L. Catalytic production of dimethylformamide from supercritical carbon dioxide. Methyl formate synthesis by hydrogenation of supercritical carbon dioxide in the presence of methanol. Selectivity for hydrogenation or hydroformylation of olefins by hydridopentacarbonylmanganese(I) in supercritical carbon dioxide. Chemtracts Org. Chem. 1996, 9 (6), 318-321. 

Supercritical carbon dioxide represents an inexpensive, environmentally benign alternative to conventional solvents for chemical synthesis. In this chapter, we delineate the range of reactions for which supercritical CO2 represents a potentially viable replacement solvent based on solubility considerations and describe the reactors and associated equipment used to explore catalytic and other synthetic reactions in this medium. Three examples of homogeneous catalytic reactions in supercritical CC are presented the copolymerization of CO2 with epoxides, ruthenium>mediated phase transfer oxidation of olefins in a supercritical COa/aqueous system, and the catalyic asymmetric hydrogenation of enamides. The first two classes of reactions proceed in supercritical CO2, but no improvement in reactivity over conventional solvents was observed. Hythogenation reactions, however, exhibit enantioselectivities superior to conventional solvents for several substrates. 

Nolen, S., Lu, 1., Brown, 1., et al. (2001). Olefin epoxidations using supercritical carbon dioxide and hydrogen peroxide without added metallic catalysts or peroxy acids, Ind Eng. Chem. Res., 41, pp. 316-323. 

PG Jessop, T Dcariya, R Noyori. Selectivity for hydrogenation or hydroformylation of olefins by hydridopentacarbonylmanganese(I) in supercritical carbon dioxide. Organometallics 14 1510-1513, 1995. 

---