Premium
Selective Hydrodeoxygenation of Vegetable Oils and Waste Cooking Oils to Green Diesel Using a Silica‐Supported Ir–ReO x Bimetallic Catalyst
Author(s) -
Liu Sibao,
Simonetti Trent,
Zheng Weiqing,
Saha Basudeb
Publication year - 2018
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201800321
Subject(s) - hydrodeoxygenation , hydrogenolysis , decarbonylation , chemistry , catalysis , organic chemistry , aldehyde , yield (engineering) , vegetable oil refining , selectivity , materials science , biodiesel , metallurgy
High yields of diesel‐range alkanes are prepared by hydrodeoxygenation of vegetable oils and waste cooking oils over ReO x ‐modified Ir/SiO 2 catalysts under mild reaction conditions. The catalyst containing a Re/Ir molar ratio of 3 exhibits the best performance, achieving 79–85 wt % yield of diesel‐range alkanes at 453 K and 2 MPa H 2 . The yield is nearly quantitative for the theoretical possible long‐chain alkanes on the basis of weight of the converted oils. The catalyst retains comparable activity upon regeneration through calcination. Control experiments using probe molecules as model substrates suggest that C=C bonds of unsaturated triglycerides and free fatty acids are first hydrogenated to their corresponding saturated intermediates, which are then converted to aldehyde intermediates through hydrogenolysis of acyl C−O bonds and subsequently hydrogenated to fatty alcohols. Finally, long‐chain alkanes without any carbon loss are formed by direct hydrogenolysis of the fatty alcohols. Small amounts of alkanes with one carbon fewer are also formed by decarbonylation of the aldehyde intermediates. A synergy between Ir and partially reduced ReO x sites is discussed to elucidate the high activity of Ir–ReO x /SiO 2.