Organosilane-assisted synthesis of EU-1 nanozeolite aggregates with improved activity in catalytic cracking of n-hexane.

• EU-1 zeolite crystal sizes are shortened to nanoscale with the presence of TPOAC. • EU-1 nano zeolite aggregates expose more external acid sites and accessible volume. • Refining of EU-1 crystal sizes improves the accessibility and utilization degree of acid sites. • EU-1 nano zeolite aggregates show higher n-hexane cracking activity than parent EU-1. One-dimensional microporous zeolite, EU-1, exhibits more favorable selectivity of propylene in cracking of petroleum components. However, it faced the problem of low catalytic activity for the poor utilization of active sites. In this work, dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC) was used to functionalize protozeolitic units and inhibit the excessive growth of crystals by the long hydrophobic alkyl chain. The introduction of TPOAC decreased the crystal sizes into nanoscale, enhanced the mesoporous volume of EU-1 zeolite, and exposed more external acid sites. Moreover, TPOAC could interact with Al species, and in this case, fewer Al atoms were incorporated into the zeolite framework, reducing the acid strength and amount. Intelligent gravitation analyzer test indicated that the zeolite prepared with the presence of 0.30 g TPOAC exhibited the largest accessible volumes in n-hexane adsorption, and the highest accessibility of acid sites, which synergistically promoted cracking of n-hexane for the production of light olefins. [ABSTRACT FROM AUTHOR]