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Highly dispersed rhodium/polyphosphine metal catalysts: on the steric control of selectivity in the hydrogenation of polyunsaturated hydrocarbons

1987; Science Press; Volume: 40; Issue: 2 Linguagem: Inglês

10.1016/0304-5102(87)80036-6

1873-3131

Sergio Sgorlon, Francesco Pinna, Giorgio Strukul,

Organometallic Complex Synthesis and Catalysis

Abstract A series of rhodium metal catalysts dispersed on styrene-2% divinyl-benzene copolymer, functionalized with different amounts of phosphine groups, are studied in the selective hydrogenation of 1,5-cyclooctadiene, acetylene and 1,3-butadiene. The activity and selectivity are analyzed as a function of the molar ratio between the total phosphorus content and the surface rhodium (P/Rh s ). The influence on the selectivity of the electron density, particle morphology and steric hindrance of the phosphine groups has been evaluated. The partial hydrogenation of dienes to monoenes appears to be always favored by an increase in the steric hindrance around the metal surface, and in some cases it is possible to increase significantly the selectivity of the catalysts.