a process for the liquid phase adsorptive separation of 4 , 4 &# 39 ;- dichlorodiphenylsulfone from crystallization residue feed mixture also containing other dcdps isomers . the feed is contacted with an x or y type zeolite , substituted with a cation of a group ia or iia metal or ammonium . the other isomers are selectively adsorbed to the substantial exclusion of 4 , 4 &# 39 ;- dcdps . the 4 , 4 &# 39 ;- dcdps is recovered in high purity by fractionating the raffinate to recover the desorbent , aliphatic alcohols having 4 - 8 carbon atoms either used alone or diluted with an aromatic compound .