Abstracts Book - IMRC 2018

• SF3-O029 Invited Talk
MECHANISTIC ANALYSES AND CATALYTIC REQUIREMENTS FOR
HYDRODEOXYGENATION OF PHENOLIC COMPOUNDS ON
TRANSITION METAL CLUSTERS
Ya-Huei (cathy) Chin 1 , Junnan Shangguan 1
1 University of Toronto, Department of Chemical Engineering and Applied Chemistry, Canada.
Hydrodeoxygenation of phenolic compounds (guaiacol, catechol, phenol, anisol)
derived from lignin is an important chemistry for the synthesis of value-added
products from biomass feedstocks. The reaction occurs on transition metal
clusters and involves a sequence of hydrogen addition and C-O activation steps,
during which reactive hydrogen species attack the phenolic derived
intermediates, breaking their aromaticity. The overall rates and selectivities for
this reaction depend markedly on the reaction environments and catalyst
identities. Here, we describe the dependence of reactivity trends on solvent
identity and interpret these trends in the context of intrinsic catalytic events. We
interrogate the individual hydrogen addition and C-O cleavage steps and their
kinetic relevance during hydrodeoxygenation of these phenolic compounds,
focusing specifically on the sequence of hydrogen addition events and of the
specific carbon positions in the benzylic ring to which the hydrogen attack
occurs. We describe the charge of the reactive hydrogen involved in these
sequential events and the catalytic roles of protic solvents in stabilizing the
intermediates leading to the transition state of the kinetically relevant step. H-
adatom addition onto the benzylic rings of these phenolic species breaks the
aromaticity, followed by rapid keto-enol tautomerization, before the kinetically
relevant H-addition or C-O cleavage steps, leading to the ring saturated or
deoxygenated products, respectively. These mechanistic insights allow us to
rationalize the reactivity trends during hydrodeoxygenation in the condensed
phase.
Acknowledgment:
We acknowledge Natural Sciences Council of Canada (NSERC), Dupont Canada,
Ontario Centre of Excellence, and Canadian Foundation for Innovation (CFI) for
their supports.
Keywords: Hydrodeoxygenation, metal clusters, phenolic
Presenting authors email: cathy.chin@utoronto.ca