A SURFACE-IMMOBILIZED MODEL-COMPOUND INVESTIGATION OF CATALYTIC REACTIONS IN DISPERSED SOLIDS

Reactions of the silica-immobilized model compounds, almost-equal-to Ph(CH2)(n)Ph (n = 1, 3, 4) and almost-equal-to PhCH2CH2OPh, with dispersed acid catalysts have been studied at 310-375-degrees-C in the solid state. Reactions of these model compounds in the presence of a small particle size (15 nm) silica-1% alumina catalyst yield products typically expected for acid-catalyzed cracking of alkylaromatics involving carbocation intermediates. The reactions of these well-defined model systems, including their dependence on the physical and chemical nature of the catalyst, provide compelling evidence that solid-state contacts between substrate and the active sites on the catalyst particles are effective in controlling reaction rates and product compositions. The results suggest that, in the early stages of coal liquefaction and hydropyrolysis, similar interactions between dispersed catalysts and coal particles may play an equally important role.