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Title: Palladium Catalysts for Fatty Acid Deoxygenation: Influence of the Support and Fatty Acid Chain Length on Decarboxylation Kinetics

Abstract

Supported metal catalysts containing 5 wt% Pd on silica, alumina, and activated carbon were evaluated for liquid-phase deoxygenation of stearic (octadecanoic), lauric (dodecanoic), and capric (decanoic) acids under 5 % H-2 at 300 A degrees C and 15 atm. On-line quadrupole mass spectrometry (QMS) was used to measure CO + CO2 yield, CO2 selectivity, H-2 consumption, and initial decarboxylation rate. Post-reaction analysis of liquid products by gas chromatography was used to determine n-alkane yields. The Pd/C catalyst was highly active and selective for stearic acid (SA) decarboxylation under these conditions. In contrast, SA deoxygenation over Pd/SiO2 occurred primarily via decarbonylation and at a much slower rate. Pd/Al2O3 exhibited high initial SA decarboxylation activity but deactivated under the test conditions. Similar CO2 selectivity patterns among the catalysts were observed for deoxygenation of lauric and capric acids; however, the initial decarboxylation rates tended to be lower for these substrates. The influence of alkyl chain length on deoxygenation kinetics was investigated for a homologous series of C-10-C-18 fatty acids using the Pd/C catalyst. As fatty acid carbon number decreases, reaction time and H-2 consumption increase, and CO2 selectivity and initial decarboxylation rate decrease. The increase in initial decarboxylation rates for longer chain fattymore » acids is attributed to their greater propensity for adsorption on the activated carbon support.« less

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1210994
DOE Contract Number:
DE-AR0000011
Resource Type:
Journal Article
Resource Relation:
Journal Name: Topics in Catalysis; Journal Volume: 55; Journal Issue: 4-Mar
Country of Publication:
United States
Language:
English

Citation Formats

Ford, JP, Immer, JG, and Lamb, HH. Palladium Catalysts for Fatty Acid Deoxygenation: Influence of the Support and Fatty Acid Chain Length on Decarboxylation Kinetics. United States: N. p., 2012. Web. doi:10.1007/s11244-012-9786-2.
Ford, JP, Immer, JG, & Lamb, HH. Palladium Catalysts for Fatty Acid Deoxygenation: Influence of the Support and Fatty Acid Chain Length on Decarboxylation Kinetics. United States. doi:10.1007/s11244-012-9786-2.
Ford, JP, Immer, JG, and Lamb, HH. 2012. "Palladium Catalysts for Fatty Acid Deoxygenation: Influence of the Support and Fatty Acid Chain Length on Decarboxylation Kinetics". United States. doi:10.1007/s11244-012-9786-2.
@article{osti_1210994,
title = {Palladium Catalysts for Fatty Acid Deoxygenation: Influence of the Support and Fatty Acid Chain Length on Decarboxylation Kinetics},
author = {Ford, JP and Immer, JG and Lamb, HH},
abstractNote = {Supported metal catalysts containing 5 wt% Pd on silica, alumina, and activated carbon were evaluated for liquid-phase deoxygenation of stearic (octadecanoic), lauric (dodecanoic), and capric (decanoic) acids under 5 % H-2 at 300 A degrees C and 15 atm. On-line quadrupole mass spectrometry (QMS) was used to measure CO + CO2 yield, CO2 selectivity, H-2 consumption, and initial decarboxylation rate. Post-reaction analysis of liquid products by gas chromatography was used to determine n-alkane yields. The Pd/C catalyst was highly active and selective for stearic acid (SA) decarboxylation under these conditions. In contrast, SA deoxygenation over Pd/SiO2 occurred primarily via decarbonylation and at a much slower rate. Pd/Al2O3 exhibited high initial SA decarboxylation activity but deactivated under the test conditions. Similar CO2 selectivity patterns among the catalysts were observed for deoxygenation of lauric and capric acids; however, the initial decarboxylation rates tended to be lower for these substrates. The influence of alkyl chain length on deoxygenation kinetics was investigated for a homologous series of C-10-C-18 fatty acids using the Pd/C catalyst. As fatty acid carbon number decreases, reaction time and H-2 consumption increase, and CO2 selectivity and initial decarboxylation rate decrease. The increase in initial decarboxylation rates for longer chain fatty acids is attributed to their greater propensity for adsorption on the activated carbon support.},
doi = {10.1007/s11244-012-9786-2},
journal = {Topics in Catalysis},
number = 4-Mar,
volume = 55,
place = {United States},
year = 2012,
month = 3
}
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  • Abstract not provided.
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