Catalytic Conversion of Fatty Acids Mixture to Liquid Fuel and Chemicals over Composite Microporous/Mesoporous Catalysts

Composite catalysts composed of microporous HZSM-5 and mesoporous MCM-41/SBA-15 molecular sieve materials were synthesized using the seeding method. The mesoporous materials containing pure silica and aluminum were coated on the microporous HZSM-5 zeolite. The catalytic conversion of a mixture of palm-oil-based fatty acids to the liquid fuel containing a gasoline fraction and aromatics was studied over the composite catalysts. The reaction was conducted in a fixed-bed microreactor at a temperature of 723 K and weight hourly space velocity of 2.5 h-1. The maximum conversion of the fatty acids mixture was 98 wt % over the composite catalyst with 30 wt % coating of purely siliceous SBA-15 over HZSM-5. The maximum gasoline fraction yield of 44 wt % was obtained with a 20-wt %-pure-siliceous-MCM-41-coated HZSM-5 composite catalyst. The selectivity for the production of benzene, toluene, and xylene (BTX) aromatics in the organic liquid product was enhanced over the mesophase aluminum-containing composite catalysts, compared to the mesoporous MCM-41 or microporous HZSM-5 catalysts alone.