Fabrication of intracrystalline mesopores within zeolite Y with greatly decreased templates

Abstract

Zeolite Y with intracrystalline mesopores has been emerging as one of the most potential materials in the catalytic cracking of large molecules. Our group has reported the synthesis of zeolite Y with intracrystalline mesopores with the formula [(CH₃O)₃SiC₃H₆N(CH₃)₂C₁₈H₃₇]Cl (denoted as “TPOACl”). However, the fabrication of mesoporous zeolite Y with a decreased organic template remains a significant challenge. In this study, a novel surfactant [(CH₃O)₃SiC₃H₆N(CH₃)₂C₁₆H₃₃]Cl (denoted as “TPHAC”) was designed and synthesized using low-cost industrial raw materials, which was found suitable for the formation of mesoporosity utilizing greatly decreased amount of the surfactant. The possible differences in the synthesis mechanisms of TPOACl and TPHAC have been discussed. The enhanced hydrophilicity of the hydroxyl groups and the subsequent decrease in the micelle aggregation number (MAN) are proposed to be the key to underline the decreased amount of surfactant in the successful synthesis. The material shows excellent hydrothermal stability and a higher mesoporous surface area ratio than TPOACl. The prepared mesoporous zeolite Y showed much higher catalytic activity and selectivity in heavy oil cracking than that prepared from TPOACl.