Sulphonated polystyrene resins: acidities and catalytic activities

A flow microcalorimetric technique for characterising the acidities of sulp honated polystyrene resins by ammonia adsorption from the gas phase has bee n applied to a series of macroporous and gel-type resin catalysts. The rela tionship between acidities measured using this technique and catalytic acti vities towards liquid phase reactions has been examined using two acid-cata lysed test reactions. Results show that catalytic activities are not relate d in a simple way to the concentrations of acid sites measured by ammonia a dsorption, but there is a useful correlation between the strengths of the a cid sites measured in this way and catalytic activities of the resins. We c onclude that acid site strength, based on ammonia adsorption and used alone , can be a useful indicator of activity for this type of acid catalyst. (C) 1999 Elsevier Science B.V. All rights reserved.