Patent ID: 7932332

Claim:
A process for preparing a singly ethylenically unsaturated isobutene polymer comprising at least 80% by weight of isobutene in which the sum of the proportions of molecules having the double bond in the α position and molecules having the double bond in the β position is at least 75 mol %, comprising: polymerizing isobutene in the liquid phase in the presence of a dissolved or dispersed catalyst complex which comprises (i) one or more electron donors and (ii) a compound of formula I H a Me b [MF x]c (I) where Me is a metal in the oxidation state m, M is at least one element, in the oxidation state n, of groups 2, 3, 4, 5, 10, 11, 13, 14 and 15 of the Periodic Table of the Elements according to the IUPAC notation, a is an integer ≧1, b is an integer ≧0, x is an integer ≧2, c is [(a+mb)/(x−n)], wherein the catalyst is free of BF 3 when HBF 4 is the compound of formula (I), and wherein the electron donor is at least one selected from the group consisting of polyvinyl alcohols, polyvinylamine, polyethers, polyalkylenamines, polyalkylenimines, polyamides and polyketones.