This invention relates to a process for the treatment of strongly acidic cation exchange resin catalysts based on styrene/divinyl benzene copolymerizates.
Recently, cation exchange resin catalysts have been employed in processes for the ecologically beneficial implementation of acid-catalyzed syntheses. The syntheses in question are for instance esterifications, splitting of esters, hydrolyses, condensations, hydrations as well as alkylations and acetylations of aromatics. Unlike liquid acids, they have the advantage that the catalyst can be easily separated from the product and that no waste acid mixtures are produced as in the conventional homogeneous catalysis.
A prerequisite for the practical use of a solid cation exchanger instead of a liquid acid is, in addition to sufficient selectivity and space/time yield, the thermal stability of the copolymerizates under the respective reaction conditions.
Strongly acidic styrene/divinyl benzene copolymerizates, the core of which has been substituted with halogen, are particularly thermally stable and are used at temperatures in the range of 100.degree. to 200.degree. C. for acid-catalyzed syntheses, such as for the hydration of lower olefins or for alkylation reactions.