Heterogeneous catalysis in organic synthesis. Part 9. Specific site solvent effects in catalytic hydrogenations
1994; Science Press; Volume: 87; Issue: 1 Linguagem: Inglês
10.1016/0304-5102(93)e0215-3
ISSN1873-3131
AutoresRobert L. Augustine, Prapapan Techasauvapak,
Tópico(s)Catalysis for Biomass Conversion
ResumoThe hydrogenation of 4-methyl-1-cyclohexene was run in several different solvents over a series of single turnover (STO) characterized 8.06% Pt/SiO2 catalysts. From the reaction rate data specific site turnover frequencies (TOFs) were obtained for each of the three STO saturation sites in each solvent. In all solvents it was found that the 3MR sites are the most reactive. Taking the heptane data as the standard, it was found that ethyl acetate adsorbed somewhat on the 3MI and 3MH sites but does not affect the reactivity of the 3MR sites. In THF and ethanol the specific site TOFs were all decreased with ethanol having more of an effect than THF. These data provide a good example of the importance of the competitive adsorption of the solvent in a heterogeneously catalysed reaction.
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