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Direct conversion of glycerol to n-propanol over a tandem catalytic dehydration-hydrogenation system
Author(s)
Solos, Thanasak
Methiritthikul, Napanot
Homla-Or, Chanakran
Duangchan, Preedawan
Date Issued
June 30, 2022
Type
Article
Abstract
The direct dehydration-hydrogenation of glycerol to n-propanol over a tandem catalytic system containing HZSM-5 (Si/Al ∼13) and supported Ni catalysts was studied under atmospheric H2. Complete glycerol conversion to acrolein and propionaldehyde (>82% selectivity) was optimized for dehydration in the first bed (HZSM-5) at 300 °C. Ni/MgO, Ni/SiO2, Ni/Mg-Al-LDH, Ni/TiO2, and Ni/Al2O3 (20 wt% Ni loading) were used as hydrogenation catalysts in the second bed at 175 °C. Without the interference of glycerol from the first bed, the acrolein and propionaldehyde produced were hydrogenated to n-propanol (∼90% selectivity). Nevertheless, propanoic acid was observed as a minor product from water reduction by propionaldehyde. The cause of deactivation was investigated for the second beds (Ni/SiO2), where the formation of high MW products was evidenced. While the catalysts can be simply regenerated by calcining in air at 450 °C, HZSM-5¦20Ni/Al2O3 with high Ni dispersion provides a higher stability and n-propanol yield (>73%) compared to other tandem catalysts.
Citation
Catalysis Science and Technology, 12(16), 5053-5066, 2022