Highly selective hierarchical ZSM-5 from kaolin for catalytic cracking of Calophyllum inophyllum oil to biofuel

Upgrading the inferior properties of Calophyllum inophyllum oil via catalytic cracking into biofuel required a porous heterogeneous acid catalysts. Hierarchical ZSM-5 (Hi-ZSM-5(K)) produced from desilication of kaolin-derived ZSM-5 was employed as catalyst and the activity was compared with hierarchical ZSM-5 obtained from templating method (Hi-ZSM-5(T)). Catalytic cracking of Calophyllum inophyllum oil was carried out in one-pot reaction at 475 °C for 120 min under the flow of H₂ and the products analysed using GC-MS were consisted of the mixtures of alkane, alkene, oxygenated carbon and aromatics compound. The advantages of desilication method for the formation of highly selective hierarchical ZSM-5 was observed when the catalyst exhibited enhanced acidity with mesopores diameter of 2–5 nm to give 93% conversion and high selectivity towards light C7–C9 hydrocarbons. However, Hi-ZSM-5(T) showed low acidity to give only 43% conversion, and selectivity towards C11–C12 hydrocarbons due to the mesopores diameter of 3–12 nm. The activity of hierarchical ZSM-5 was also compared with microporous ZSM-5 that produced biofuel with approximately equal distribution of C5–C18 hydrocarbons. The role of hierarchical structures was further discussed on the composition of aromatics compound, oxygenates content and alkene/alkane ratios of the biofuel.