Studies in surface science and catalysis vol:78 pages:527-534
Binary mixtures of acetic, propionic and butyric acid are converted in the vapor phase over zeolite H-T. From hydroxyl stretching vibration spectra of zeolite H-T with adsorbed butyric acid, it is concluded that the carboxylic acids have access to the different proton locations in this zeolite. The acids undergo ketonization reactions inside the erionite cavities of the zeolite, and dehydration reactions into anhydrides on the outer surface of the zeolite crystal. The ketonization activity and selectivity is rationalized by transition-state shape-selectivity in erionite cages. Zeolite H-T is particularly suitable for converting an equimolar mixture of propionic and butyric acid into 3-hexanone.