Jatropha curcas L. oil hydroconversion over hydrodesulfurization catalysts for biofuel production

The process of the catalytic hydroconversion of vegetable oil (CHVO) involves the transformation of vegetable oil triglycerides to linear chain alkanes via hydrodeoxygenation (HDO) reactions followed by conventional hydrocracking reaction pathways to generate multiple hydrocarbon compounds similar to heavy vacuum oil. The CHVO process was applied to Jatropha curcas oil using commercial hydrodesulfurization (HDS) Co-Mo/Al₂O₃ and Ni-Mo/Al₂O₃ catalysts under HDS operating conditions. The reaction products (i.e., intermediates and final compounds) from the hydroconversion of J. curcas seed oil triglycerides were identified by Fourier transform infrared spectroscopy and mass spectroscopy. The CHVO process was performed using both HDS catalysts. The process occurs through three reaction pathways including decarbonylation, decarboxylation and hydrodeoxygenation in which the carboxyl group is removed from the fatty acids to produce products similar to fossil fuels. The presence of intermediate deoxygenation products, such as aldehydes, suggests a sequential triglyceride hydrodeoxygenation mechanism. Then, the fully deoxygenated intermediates undergo hydrocracking and hydroisomerization reactions via carbenium ion chemistry to generate renewable petroleum products that are equivalent to liquid fuels such as gasoline, jet fuel and diesel.