Hierarchical hzsm‐5 for catalytic cracking of oleic acid to biofuels

Abstract

Solid acid catalyzed cracking of waste oil‐derived fatty acids is an attractive route to hydrocarbon fuels. HZSM‐5 is an effective acid catalyst for fatty acid cracking; however, its microporous nature is susceptible to rapid deactivation by coking. We report the synthesis and application of hierarchical HZSM‐5 (h‐HZSM‐5) in which silanization of pre‐crystallized zeolite seeds is employed to introduce mesoporosity during the aggregation of growing crystallites. The resulting h‐HZSM‐5 comprises a disordered array of fused 10–20 nm crystallites and mesopores with a mean diameter of 13 nm, which maintain the high surface area and acidity of a conventional HZSM‐5. Mesopores increase the yield of diesel range hydrocarbons obtained from oleic acid deoxygenation from ~20% to 65%, attributed to improved acid site accessibility within the hierarchical network.