Deoxygenation of vegetable oils for the production of renewable diesel: Improved aerogel based catalysts

[Display omitted] •Catalysts were tested for the deoxygenation of soybean oil to produce green diesel.•Aerogel catalysts produced over 4 times more hydrocarbons than the typical catalyst.•Aerogel catalysts were prepared using supercritical and subcritical drying methods.•Effects of catalyst characteristics, temperature and time have been discussed.•Higher catalyst acidity increases the degree of cracking of the product. The performances of two novel aerogel based catalysts on the production of renewable diesel were compared with an impregnated catalyst for the deoxygenation of undiluted soybean oil. The catalysts were extensively characterized. The aerogel catalysts exhibited a remarkably higher production of hydrocarbons with a reaction rate over 4 times that of the impregnated catalyst and selectivity to uncracked hydrocarbon in excess of 90%. All catalysts exhibited zero order behavior in the undiluted condition tested and no deactivation was detected. The specific acidity appears to be directly linked to the degree of cracking achieved by the catalyst, with the impregnated catalyst being both the most acid and exhibiting the higher degree of cracking, thus lowering its selectivity. The subcritically dried aerogel catalyst had the best overall performance, exhibiting low levels of cracking and high selectivity to larger hydrocarbons, which has been linked to smaller crystallites and higher specific area.