Abstract: A process is provided for the halomethylation of the aromatic groups in an isoolefin-vinylidene aromatic monomer polymer by the in situ generation of the halomethylating species formed by the reaction of a methoxy alkoxy methane with a thionyl halide, the halomethylation of the polymer being catalyzed by a Lewis acid.

Abstract: A halogenated butyl rubber is prepared by a process wherein a monomer charge comprising isobutylene and conjugated diolefin having the formula ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 which may be the same or different are a methyl group or a hydrogen atom and X is bromine or chlorine together with an initiator having the formula ##STR2## wherein each R.sub.4 is an alkyl, aryl or aralkyl group, Y is preferably an alkoxy, hydroxy, carboxyl or halide, and n is a positive whole number from 1 to 3 are introduced into a suitable reaction vessel in a specified ratio at a temperature of from about -90.degree. to -10.degree. C., a solution of a Lewis acid is added and the monomers are copolymerized at said temperature to form said halogenated butyl rubber, and the halogenated rubber is recovered from solution.

Abstract: A process for producing EP and EPDM polymers with a reduction in fouling is provided, which process comprises polyemrizing ethylene, an alpha-olefin and a nonconjugated diolefin (if utilized) in a polymerization medium comprising a hydrocarbon diluent at a temperature of from about -50.degree. C. to about 150.degree. C. in the presence of a catalyst system comprising (a) a vanadium compound, (b) diethyl aluminum chloride, ethyl aluminum sesquichloride or ethyl aluminum dichloride and (c) an organo aluminum compound of the formula R.sub.3 Al wherein R is an alkyl group having from 8 to 12 carbon atoms and, optionally, triethyl aluminum, the molar ratio of chloride in diethyl aluminum chloride to the total aluminum content in (b) and (c) being from about 0.7:1 to about 0.95:1, the molar ratio of the chloride in ethyl aluminum sesquichloride to the total aluminum content in (b) and (c) being from about 0.7:1 to about 1.