The Hydrodeoxygenation of Glycerol over NiMoSx: Catalyst Stability and Activity at Hydropyrolysis Conditions. Issue 1 (25th November 2020)

• Record Type: Journal Article
• Authors: Anderson, Anthony D.; Lanci, Michael P.; Buchanan, J. Scott; Dumesic, James A.; Huber, George W.
• Is Part Of: ChemCatChem. Volume 13:Issue 1(2021)
• Page Start: 425
• Page End: 437
• Publication Date: 2020-11-25
• Subjects: biomass -- green chemistry -- hydrodeoxygenation -- hydropyrolysis -- molybdenum sulfide; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.202001289
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: Catalytic activity tests were run to elucidate the chemistry and catalyst stability for the hydrodeoxygenation of glycerol and other aliphatic oxygenates over a NiMoSx /Al2 O3 catalyst at different pretreatments at hydropyrolysis conditions in a continuous flow reactor. Reactivity metrics were developed to quantify and compare the reactivity of NiMo for deoxygenation, hydrogenation, and C−C cleavage. Activity experiments showed sulfided NiMo and reduced NiMo catalysts had similar deoxygenation and hydrogenation activity for glycerol HDO at 400 °C and 270 psig H2 with the NiMoSx catalyst showing higher C−C cleavage activity. Without a sulfur co‐feed, both the NiMoSx and NiMoOx catalysts lost >40 % deoxygenation activity over 30 h time on stream. With a 2100 ppm H2 S co‐feed the NiMoSx catalyst showed a 12 times decrease in the deactivation rate for deoxygenation and 6 time decrease in the deactivation rate for hydrogenation. The main products at high conversion were propylene, propane, ethylene, methane, CO, methanol, ethanol, and 1‐propanol. At low conversion, the major products were unsaturated allyl alcohol, acrolein, hydroxyacetone, and acetaldehyde. With no H2 S co‐feed at short contact times, there was a significant amount of carbon loss possibly due to condensation reactions, while at 2100 ppm H2 S in the feed, the carbon balance was 102.4 %. Temperature programmed oxidation of the spent NiMoSx catalysts after 30 h of glycerol HDO without an H2 S co‐feed showed that one of the causes of deactivation was coking. Abstract : Green chemistry : Both NiMoOx /Al2 O3 and NiMoSx /Al2 O3 form reactive intermediates over a short contact time followed by subsequent stabilization through deoxygenation and hydrogenation reactions. NiMoSx /Al2 O3 loses >50 % of its deoxygenation and hydrogenation activity over 30 h with no sulfur co‐feed, with a 12 and 6 times improvement in deoxygenation and hydrogenation stability with a 2100 ppm H2 S co‐feed.