Synthesis of strong acid resins from macroporous styrene-divinylbenzene copolymers: Is diluent extraction step necessary?

Abstract

Strong acidic cation-exchange resins derived from the same batch of styrene–divinylbenzene copolymers with and without acetone washing are compared with respect to ion-exchange capacity and leachable organics. The capacity was the same throughout 10 cycles of resin exhaustion and regeneration. Ultraviolet spectra showed the same level of leachable organics in the two cases compared. Fourier transform infrared spectra were also similar. The results are explained on the basis of the fact that n-heptane and toluene used as diluents were removed through a steam distillation phenomenon during the copolymer curing step. Residual homopolymers were washed away with water after the sulfonation of the copolymers just like acetone washing of them from the copolymer. Acetone washing, which accounts for about 80% of the cost of the chemicals in the copolymer synthesis, can be eliminated in the case of diluents such as n-heptane and toluene, making the process simple, economical, and environment friendly. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers