Reaction Pathways and Intermediates in Selective Ring Opening of Biomass-Derived Heterocyclic Compounds by Iridium

Journal Article · Thu Sep 08 00:00:00 EDT 2016 · ACS Catalysis

DOI:https://doi.org/10.1021/acscatal.6b01310· OSTI ID:1388770

Jenness, Glen R. ^[1]; Wan, Weiming ^[2]; Chen, Jingguang G. ^[2]; Vlachos, Dionisios G. ^[1]

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1. Energy Frontier Research Centers (EFRC) (United States). Catalysis Center for Energy Innovation (CCEI); Univ. of Delaware, Newark, DE (United States)
2. Energy Frontier Research Centers (EFRC) (United States). Catalysis Center for Energy Innovation (CCEI); Univ. of Delaware, Newark, DE (United States); Columbia Univ., New York, NY (United States)

While the catalytic hydrogenolysis of biomass-derived aromatic cyclic compounds to functionalized long chain alcohols and polyols has been known for decades, the factors that control the selectivity remain either unknown or controversial. Previous reports have hypothesized full ring saturation of the aromatic ring is necessary prior to hydrogenolysis. Contradictorily, recent studies have shown hydrogenolysis occurs prior to the saturation of the conjugated bonds. Furthermore, it has been assumed the functional groups present are fully reduced prior to hydrogenolysis; however, this has not been shown a priori. In order to resolve these controversies, we combine density functional theory and high-resolution electron energy loss spectroscopy (HREELS) to probe the catalytic hydrogenolysis of saturated and unsaturated heterocyclic molecules (furan, furfural, furfuryl alcohol, and tetrahydrofurfuryl alcohol) on iridium. Our results reveal that full saturation of the aromatic ring is not only unnecessary but leads to slower kinetics and differing selectivities. In contrast to previous studies, we show selective partial ring saturation can enhance the kinetics of the hydrogenolysis process. We report reduction/oxidation of the functional group leads to a change in the electronegativity, resulting in a change in selectivity. These results provide important mechanistic insights allowing for further improvement of catalysts for the effective transformations of biomass-derived oxygenates to value-added products.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Catalysis Center for Energy Innovation (CCEI); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of Delaware, Newark, DE (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0001004; AC02-05CH11231
• OSTI ID: 1388770
• Journal Information: ACS Catalysis, Vol. 6, Issue 10; Related Information: CCEI partners with the University of Delaware (lead); Brookhaven National Laboratory; California Institute of Technology; Columbia University; University of Delaware; Lehigh University; University of Massachusetts, Amherst; Massachusetts Institute of Technology; University of Minnesota; Pacific Northwest National Laboratory; University of Pennsylvania; Princeton University; Rutgers University; ISSN 2155-5435
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ring opening
furfural
furfuryl alcohol
tetrahydrofurfuryl alcohol
density functional theory
HREELS
Ir
diol
catalysis (homogeneous)
catalysis (heterogeneous)
biofuels (including algae and biomass)
bio-inspired
hydrogen and fuel cells
materials and chemistry by design
synthesis (novel materials)
synthesis (self-assembly)
synthesis (scalable processing)