Deep Cracking of Bulky Hydrocarbons into Light Products via Tandem Catalysis over Uniform Interconnected ZSM‐5@AlSBA‐15 Composites

Abstract

AbstractDeep cracking of bulky hydrocarbons on zeolite‐containing catalysts into light products with high activity, desired selectivity, and long‐term stability is demanded but challenging. Herein, the efficient deep cracking of 1,3,5‐triisopropylbenzene (TIPB) on intimate ZSM‐5@AlSBA‐15 composites via tandem catalysis is demonstrated. The rapid aerosol‐confined assembly enables the synthesis of the composites composed of a continuous AlSBA‐15 matrix decorated with isolated ZSM‐5 nanoparticles. The two components at various ZSM‐5/AlSBA‐15 mass ratios are uniformly mixed with chemically bonded pore walls, interconnected pores, and eliminated external surfaces of nanosized ZSM‐5. The typical composite with a ZSM‐5/AlSBA‐15 mass ratio of 0.25 shows superior performance in TIPB cracking with outstanding activity (≈100% conversion) and deep cracking selectivity (mass of propylene + benzene > 60%) maintained for a long time (> 6 h) under a high TIPB flux (2 mL h−1), far better (several to tens of times higher) than the single‐component and physically mixed catalysts and superior to literature results. The high performance is attributed to the cooperative tandem catalytic process, that is, selective and timely pre‐cracking of TIPB to isopropylbenzene (IPB) in AlSBA‐15 and subsequently timely diffusion and deep cracking of IPB in nanosized ZSM‐5.