It is well known in the art that Friedel-Crafts catalysts may be used in conjunction with aluminum alkyls and alkyl aluminum halides to polymerize various olefins and isoolefins. For example, copolymers of 1-butene and propylene are prepared using a catalyst comprising diethyl aluminum chloride and the reaction product of titanium tetrachloride and aluminum; see, for example, U.S. Pat. No. 3,332,921, which is incorporated herein by reference.
It is known that polymers and copolymers of Type II and Type III olefins may be prepared using a catalyst comprising a Friedel-Crafts halide and an aluminum compound selected from the groups consisting of trialkyl aluminum and dialkyl aluminum halide wherein the ratio of Friedel-Crafts halide to aluminum compound is a minimum of 1; see, for example, U.S. Pat. No. 3,066,123 which is incorporated herein by reference. More recently, isobutylene has been polymerized at temperatures of about -20.degree. to 50.degree. C. using a catalyst comprising aluminum compounds having the general formula AlR.sub.n X.sub.3-n where R is alkyl, allyl or aralkyl, X is halogen or hydrogen, and n is an integer from 1 to 3 in conjunction with vanadyl chloride. The reaction may also be carried out using a dialkyl aluminum halide or alkyl aluminum dihalide in conjunction with SnCl.sub.4 ; see, for example, U.S. Pat. No. 3,324,094.
Finally, it is well known that aluminum dialkyl halides or aluminum hydrides alone do not initiate cationic polymerization reactions, but require the presence of large molar proportions of cocatalysts such as transition metal halides.
USPTO Backgrounds
USPTO Backgrounds