Catalytic properties of hierarchical mesoporous zeolites templated with a mixture of small organic ammonium salts and mesoscale cationic polymers.

Crystals of zeolites with intricate micropores have been widely used in industry as heterogeneous catalysts, in particular as solid acid catalysts in the fields of oil refining and petrochemistry. However, relatively small individual micropores in zeolites such as Beta, ZSM-5, and Y strongly influence mass transport to and from the active sites located within them, severely limiting the performance of industrial catalysts.[1,2] To overcome this problem, various strategies have been successfully pursued, such as the synthesis of nanosized zeolites,[3] ultralarge-pore zeolites and zeolite analogues (VPI-5,[4] JDF-20,[5] UTD-1,[6, 7] CIT-5,[8] SSZ-53,[9] ECR-34,[10] UCSB,[11] ITQ-21,[12] IM-12,[13] and SU-M,[14, 15] among others), and ordered mesoporous materials (e.g. MCM-41,[17] SBA-15,[18] and FSM-16,[19]). However, the use of these materials is rather limited owing to the difficult separation of nanosized zeolite crystals from the reaction mixture,[3] the complexity of the templates used for the synthesis of ultralarge-pore zeolites,[6–9] and the relatively low thermal and hydrothermal stability of ordered mesoporous materials.[17–28] More recently, mesoporous zeolites from nanosized carbon templates have also been successfully synthesized,[29–32] but their industrial applications are still limited by the complexity of the synthetic procedure involved and the hydrophobicity of the carbon templates.