Lewis acid polymerization catalyst

A method of producing a polyether alcohol, the method comprising:

• feeding an initiator into a reactor, the initiator having a nominal hydroxyl functionality of at least 1;
• feeding one or more monomers into the reactor, the one or more monomers being an alkylene oxide;
• feeding a polymerization catalyst into the reactor, the polymerization catalyst being a Lewis acid catalyst having a general formula M(R1)1(R2)1(R3)1(R4)0 or 1, whereas M is boron, aluminum, indium, bismuth or erbium, R1, R2, R3, and R4 are each independent, R1 includes a first fluoro/chloro or fluoroalkyl-substituted phenyl group, R2 includes a second fluoro/chloro or fluoroalkyl-substituted phenyl group, R3 includes a third fluoro/chloro or fluoroalkyl-substituted phenyl group or a first functional group or functional polymer group, optional R4 is a second functional group or functional polymer group;
• separate from feeding the initiator into the reactor, feeding a hydrogen bond acceptor additive into the reactor, the hydrogen bond acceptor additive being a C2 to C20 organic molecule having at least two hydroxyl groups, of which two hydroxyl groups are situated in 1,2-, 1,3-, or 1,4-positions on the organic molecule;
• and
• allowing the initiator to react with the one or more monomers in the presence of the polymerization catalyst and the hydrogen bond acceptor additive to form a polyether alcohol having a number average molecular weight greater than a number average molecular weight of the initiator.