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Reduction of Propanoic Acid over Pd‐Promoted Supported WO x Catalysts
Author(s) -
Kammert James D.,
Brezicki Gordon,
Miyake Naomi,
Stavitski Eli,
Davis Robert J.
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201901302
Subject(s) - propanoic acid , catalysis , chemistry , selectivity , inorganic chemistry , incipient wetness impregnation , infrared spectroscopy , phosphotungstic acid , nuclear chemistry , organic chemistry
Silica‐, titania‐, and zirconia‐supported tungsten oxide catalysts were synthesized by wetness impregnation techniques. When promoted with Pd, these materials catalyzed the reduction of propanoic acid to 1‐propanol at 433 K with a selectivity of up to 92 % (13.5 % conversion) in atmospheric pressure of H 2 . Over Pd‐promoted WO x /TiO 2, the observed orders of reaction were 0.2 in H 2 and 0.7 in propanoic acid, and the apparent activation energy was 54 kJ mol −1 . In situ X‐ray absorption spectroscopy of Pd‐promoted WO x /SiO 2 revealed a slight reduction of the W from +6 to an average oxidation state of about +5 during H 2 treatment above 473 K. In situ infrared spectroscopy indicated the catalyst surface was covered mostly by propanoate species during reaction. For comparison, supported phosphotungstic acid was also evaluated as a catalyst under identical conditions, but the resulting high acidity of the catalyst was deleterious to alcohol selectivity.