The predictive power of classical transition state theory revealed in diffusion studies with MOF ZIF-8

• Reconsidering transition state theory based on new diffusion data.
• Sorption isotherm sufficient for estimating concentration dependence of diffusion.
• Variations of up to two orders of magnitude correctly predicted.
• Systems with necks between cavities as promising candidates for further quests.

Knowledge of the adsorption isotherm is demonstrated to be sufficient for predicting the concentration dependence of the diffusivity of light hydrocarbons in MOF ZIF-8. Guest molecules considered include saturated and unsaturated hydrocarbons and alcohols. Calculations are based on the application of the classical transition state theory (TST). The predictions cover concentration dependences of up to two orders of magnitude in transport diffusion and of one order in self-diffusion. In agreement with TST, self- and corrected (Maxwell–Stefan) diffusivities are seen to coincide.

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