Conversion of biomass-derived material into industrial carbon feedstocks and fuels is an important part of a green chemical economy. Deoxydehydration (DODH) of polyols into alkenes and dienes is an important reaction. Here, we have studied a molybdenum(VI) dioxo-based catalyst, dioxo(pyridine-2,6-dicarboxylato)(hexamethylphosphoramide) molybdenum (VI), and its ability to catalyze the DODH reaction. Reactions were monitored by NMR spectroscopy and GC/MS. 1-phenyl-1,2-ethanediol shows the best conversion with ~90% yield at 110°C in 48 hours when paired with PPh3 as a reductant. Other aromatic diols showed reasonable yields of ~60%. Aliphatic diols afforded relatively poor yields and conversions. A variety of reductants were studied, including zinc metal, Na2SO3, isopropyl alcohol, and carbon monoxide; each reductant was shown to be a competent reagent for DODH. The reaction kinetics were studied via in situ IR spectroscopy. Under pseudo-first order conditions of reductant, the DODH of 1-phenyl-1,2-ethanediol was found to have a rate constant of 5.47 E-5 inverse seconds at 110°C. DOSY NMR studies were used to study the speciation of the molybdenum complex under catalytic conditions.

Studies of a low-valent Molybdenum(VI)-dioxo complex as a deoxydehydration catalyst

253rd National Meeting (2017)

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