We recently reported substantial variation in apparent turnover frequencies and kinetic parameters during the catalytic decarboxylation of γ-valerolactone over a series of solid acids including MFI, SiO2-Al2O3, γ-Al2O3, and supported phosphotungstic acid. In aluminosilicates, Brønsted sites associated with framework aluminum contribute the majority of decarboxylation activity. Relative to bridging hydroxyls, coordinatively unsaturated aluminum sites are substantially less active, and they do not contribute significantly to butene production rates in materials having both framework and extraframework aluminum. Through comparison of aluminosilicates with supported heteropolyacids, decarboxylation barriers were found to scale with the deprotonation energy of Brønsted acid sites; however, the apparent decarboxylation turnover frequency of a Brønsted site did not necessarily correlate with its deprotonation energy. Here, we attempt to resolve observed differences in apparent phenomena and parameters through microkinetic analysis of the elementary reactions governing valerolactone decarboxylation over Brønsted sites. 1Kellicutt, A.B., Salary, R., Abdelrahman, O.A., and Bond, J.Q., Catalysis Science and Technology, 2015, 4, 8, 2267-2279.

Microkinetic analysis of γ-valerolactone ring opening and decarboxylation over solid acids

251st National Meeting (2016)

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