Method for preparing ester end-capped copolyether glycols

Claim 1

A process for preparing ester end-capped copolyether glycol, the process comprising (A) bringing together, under conditions suitable for reaction, (1) tetrahydrofuran; (2) an alkylene oxide containing 2 or 3 carbon atoms in its ring, or a cyclic acetal represented by the structure ##STR7## where n is 2-4 and X and X 1 are hydrogen or an alkyl radical of 1-4 carbon atoms; (3) an acylium ion precursor; and (4) as a catalyst, a homopolymer of an ethylenically unsaturated monomer (a) containing groups such that the final polymer will contain groups of the formula ##STR8## where represents the polymer chain or a segment thereof; D is hydrogen, an aliphatic or aromatic hydrocarbon radical of 1-10 carbon atoms, halogen or a segment of the polymer chain; X and Y are hydrogen, halogen or an aliphatic or aromatic hydrocarbon radical of 1-10 carbon atoms, but at least one of X or Y must be fluorine; R is a linear or branched linking group having up to 40 carbon atoms in the principal chain; and Z is hydrogen, halogen or an aliphatic or aromatic hydrocarbon radical of 1-10 carbon atoms; or a copolymer of monomer (a) with at least one other copolymerizable ethylenically unsaturated monomer (b), the homopolymer or copolymer having an equivalent weight of 950-1500 and a solubility such that no more than about 5%, by weight, dissolves in the reaction medium at the reaction temperature, and then (B) separating the resulting ester end-capped copolyether glycol from the reaction mass.