Polystyrene

cross-linked with 4% of divinylbenzene

is combined with TiCl in CS2 to form a stable complex containing 20.3% of chlorine. The TiCl4 complexed in polystyrene is resistant to water and can be stored in air at least one year. The complex is a strong solid Lewis acid and can be used to catalyze a lot of organic synthesis reactions in high yield

such as esterications

acetal formations

ketogenesis

and the Friedel-Cra-fts alkylations. The complex is also a good catalyst for polymerization of α-methyl styrene.