We have reported the application of solvatochromism in the UV-visible spectra of models of silica-supported chromophores1 to study a previously unconsidered stratification in a reaction mixture in the immediate vicinity of catalytic sites when at least one of the components of the fluid phase exhibits �epiphilicity�. Here, we report the use of solvatochromism of a tungsten dioxo chromophore coordinated to a polyhedral oligomeric silsequioxane (POSS) to probe its preferential solvatation by cyclohexene in the presence of tetrahydrofuran. We have found that the preferential solvation is reflected in the kinetics of photo-initiated hydrogenation of the cyclohexene: the reaction is zero-order in the cyclohexene over a concentration range from 0 to 75% tetrahydrofuran. The results are germane to the upgrading of biomass-derived feedstocks into fuels, where the polarizability of the reaction medium necessarily changes with conversion.Reference:1) Weber, Robert S.; Cosimbescu, Lelia; Glezakou, Vassiliki-Alexandra; Karkamkar, Abhijeet; Schwenzer, Birgit; Wang, Zheming; Preprints � American Chemical Society (2013), 58(2), 192.

Stratification of the reaction medium during photo-activated hydrogenation of cyclohexene catalyzed by POSS-supported chromophores

247th National Meeting (2014)

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