Anomalous hydrocracking of triglycerides over CoMo-catalyst-influence of reaction intermediates

Reaction intermediates have been identified and followed to understand anomalous cracking of jathropha oil triglycerides in the presence of sulphided Co-Mo/Al2O3 catalyst. Undesirable C-C coupling reactions are favoured at temperatures between 320 degrees and 340 degrees C, giving waxy oligomerization products, whereas at temperatures above 340 degrees C, direct hydrocracking of triglycerides to lighter and middle distillates were favoured. To minimize undesirable waxy oligomerization products, higher pressures (>80 bar) and higher H-2/feed ratios (>1500) were necessary. Aldol condensation and ketonization reactions between the reaction intermediates are counter-productive as they result in waxy long chain oxygenated products which tend to accumulate on the catalyst surface, choke the reactor and cause rapid catalyst deactivation. Reaction conditions have to be optimized to minimize condensation reaction during this process.