Analysis of acidic properties of zeolitic and non-zeolitic solid acid catalysts using temperature-programmed desorption of ammonia

A method of ammonia temperature-programmed desorption (TPD) for analysis of acidic property of a solid was improved by introduction of a water vapor treatment method and development of a theory for calculation of ammonia adsorption heat from the TPD pro. le. The improved method was applied to various solid acid catalysts to establish relationships between the acidic properties and catalytic performances for various acid-catalyzed reactions. Here, examples of the applications to some important acid catalysts are reviewed. The exact analysis of acidic property of Y zeolite and its change by such modi. cations as steaming and ethylenediaminetetraacetic acid ( EDTA) treatment gave a new interpretation on the generation of alkane ( paraffin) cracking activity on an ultra stable Y (USY) zeolite. The surface density and strength of acid sites on WO3/ZrO2 and SO42-/ZrO2 catalysts were determined, and their relations with catalytic activities for Friedel - Crafts type alkylation and skeletal isomerization of alkane were found.