Patent ID: 7868132
Filing Date: 2011-01-11
Classification: C08G

Abstract:
1. A method for making a composition comprising at least one multi-arm PEG amine having from 3 to about 10 arms comprising the steps of: a) reacting at a temperature of less than or equal to about 100° C., optionally in the presence of a solvent, thionyl chloride and at least one multi-arm PEG polyol having from 3 to about 10 arms, to form a multi-arm PEG chloride having at least about 95% of hydroxyl end groups of the multi-arm PEG polyol converted to chloride end groups; b) separating the multi-arm PEG chloride from unreacted thionyl chloride and the optional solvent; c) forming a reaction mixture by reacting the multi-arm PEG chloride with either aqueous ammonia or anhydrous ammonia for a time and at a temperature to form a reaction product in which at least about 95% of the chloride end groups of the multi-arm PEG chloride are converted to amine end groups, thereby generating HCl, the aqueous ammonia or the anhydrous ammonia being in sufficient quantity to prevent gelation of the reaction mixture; d) optionally, either removing HCl from the reaction product or converting the HCl to a salt by the addition of a base and removing said salt; and e) optionally removing water from the reaction product of (c) or the product of step (d).