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Abstract Zeolite reactivity depends on the solvating environments of their micropores and the proximity of their Brønsted acid sites. Turnover rates (per H⁺) for methanol and ethanol dehydration increase with the fraction of H⁺sites sharing six‐membered rings of chabazite (CHA) zeolites. Density functional theory (DFT) shows that activation barriers vary widely with the number and arrangement of Al (1–5 per 36 T‐site unit cell), but cannot be described solely by Al–Al distance or density. Certain Al distributions yield rigid arrangements of anionic charge that stabilize cationic intermediates and transition states via H‐bonding to decrease barriers. This is a key feature of acid catalysis in zeolite solvents, which lack the isotropy of liquid solvents. The sensitivity of polar transition states to specific arrangements of charge in their solvating environments and the ability to position such charges in zeolite lattices with increasing precision herald rich catalytic diversity among zeolites of varying Al arrangement. 

Reactions catalyzed within porous inorganic and organic materials and at electrochemical interfaces commonly occur at high coverage and in condensed media, causing turnover rates to depend strongly on interfacial structure and composition, collectively referred to as “solvent effects”. Transition state theory treatments define how solvation phenomena enter kinetic rate expressions, and identify two distinct types of solvent effects that originate from molecular clustering and from the solvation of such clusters by extended solvent networks. We review examples from the recent literature that investigate reactions within microporous zeolite catalysts to illustrate these concepts, and provide a critical appraisal of open questions in the field where future research can aid in developing new chemistry and catalyst design principles.