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Exploring the Myth of Nascent Hydrogen and its Implications for Biomass Conversions
Author(s) -
Fábos Viktória,
Yuen Alexander K. L.,
Masters Anthony F.,
Maschmeyer Thomas
Publication year - 2012
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201200557
Subject(s) - cyclohexanone , formic acid , chemistry , aqueous solution , cyclohexanol , stoichiometry , inorganic chemistry , hydrogen , mineral acid , water gas shift reaction , metal , catalysis , organic chemistry
Iron (and to a lesser extent manganese) in the wall of a 316 stainless steel (SS) reactor is responsible for the hydrogenation of cyclohexanone to cyclohexanol when using an aqueous formic acid solution under high temperature and pressure water (HTPW) conditions. However, not only dilute formic acid but also aqueous solutions of several other organic and mineral acids in the presence of iron are active in this reaction covering a range of aldehydes and ketones, even under ambient conditions. The stoichiometry, kinetics, and the possible mechanisms of both dihydrogen production as well as of the hydrogenation of the model compound cyclohexanone were examined. The reduction is essentially stoichiometric with respect to metallic iron, and the conversions are highly dependent on the speed of stirring as well as temperature and reactant concentrations. Importantly, it is established unequivocally that water participates in dihydrogen gas formation (hydrogen atoms originate from both the acid and water molecules) and facilitates substrate reduction.