Zeolites fit for a crown: Studying organic-framework host-guest interactions through thermogravimetric techniques

Every year millions of tons of zeolites are produced, being used as molecular sieves, hydrocracking catalysts, gas-capture materials and for emerging novel applications. There is a demand to synthesise new zeolites with bespoke frameworks, which are tailor-made for a chosen application. To achieve these ‘designer zeolites’ it is crucial to fully understand the host-guest interactions between organic additives and zeolitic frameworks. Here we have studied four different zeolites, synthesised with the same organic additive, 18-crown-6 ether, which show observable differences in the host-guest interactions. We demonstrate that the framework geometry dominates the decomposition temperature, enthalpy and mechanism. The zeolites show unique decomposition features, emphasising experimental differences in how the organic additive and framework interact. [Display omitted] •Thermogravimetric and differential thermal analysis methods were used to study the crown ether decomposition in zeolites.•There is a clear distinction in the decomposition of the 18C6 molecule in the different frameworks.•Measurable differences are seen in the host-guest interactions between organic additives and zeolite hosts.•Stronger host-guest confinement interactions are seen in zeolites with smaller pores.•Our methodology can be applied to other zeolites to study the host-guest interactions.