Acidities and catalytic activities of persulfonated poly(styrene-co-divinylbenzene) ion-exchange resins

A series of macroporous sulfonated poly(styrene-co-divinylbenzene) ion-exch ange resins with varying levels of sulfonation have been prepared. The acid ities of these resins have been measured calorimetrically by ammonia sorpti on. Catalytic activities have been measured in two liquid-phase reactions: the dehydration of 1-hexanol under how conditions and the hydration of prop ene as a batch process. The molar enthalpies of ammonia sorption show that the strength of the acid sites increases as the level of sulfonation is inc reased; catalytic activities follow the same trend. The most active resins are those that have been sulfonated at levels above one sulfonic acid group per aromatic ring ("persulfonated"). These persulfonated resins also show higher thermal stabilities than conventional resins (sulfonated at just bel ow one acid group per aromatic ring).