Ion-exchange resin-catalysed ketalization of acetone with 1,4- and 1,2-diols: use of molecular sieve in reactive distillation

Ketalization of acetone with 1,4- and 1,2-diols was carried out in the presence of cation exchange resin catalysts to obtain corresponding cyclic ketals viz. dioxepins, dioxepanes and dioxolanes. The reaction is equilibrium controlled and low conversions were achieved in batch mode. Molecular sieves in semi-batch reactive distillation mode were used to remove the water from the reaction mixture. This resulted in high conversion of the limiting diol. The batch kinetics was explained by a pseudohomogeneous model. The effects of different configurations as well as various parameters were studied in detail to arrive at optimum conditions. An engineering solution was arrived at to make the process industrially feasible. (C) 1999 Elsevier Science B.V. All rights reserved.