GB916552A - Purification of polyethers - Google Patents

Abstract

Polyethers are rendered free from basic inorganic materials used as catalysts by treating with an aliphatic dicarboxylic acid containing 2 to 10 carbon atoms in the molecule. Examples of such acids are oxalic, malonic, succinic, glutaric, adipic, alkyladipic, pimelic, suberic, azelaic and sebacic acids. Mixtures of acids may be used. The polyethers are particularly those obtained by polymerizing an a ,b -alkylene oxide, e.g. ethylene, propylene-1,2 and butylene-1,2 and -2,3 oxides, in the presence of an alkaline catalyst and optionally in the presence of a compound containing one or more reactive hydrogen atoms. The inorganic materials are generally compounds of alkali and alkaline earth metals, particularly potassium and sodium hydroxides. Treatment may be effected at 25 DEG to 150 DEG C., preferably 90 DEG to 110 DEG C., when the polyether is liquid. Water is preferably added before or after the addition of the acid and before the removal of volatile and insoluble materials. A basic material insoluble in the polyether is also preferably added before these removals, optionally in conjunction with a filter aid such as kieselguhr. And the polyether may be treated with an absorbent material, e.g. finely divided carbon, before the final filtration. The examples describe the preparation and purification of polyethers prepared by reacting propylene oxide with diethylene glycol, 1,1,1-trimethylolpropane and glycerol respectively. In Example 6, after treatment with adipic acid and kieselguhr, there are added finely divided carbon and 2-(a -methylcyclohexyl)-4,6-dimethyl phenol before removal of volatiles &c. Specification 864,097 is disclaimed.ALSO:Polyethers are rendered free from basic inorganic materials used as catalysts by treating with an aliphatic dicarboxylic acid containing 2 to 10 carbon atoms in the molecule. Examples of such acids are oxalic, malonic, succinic, glutaric, adipic, p alkyladipic, pimelic, suberic, azelaic and sebacic acids. Mixtures of acids may be used. The polyethers are particularly those obtained by polymerizing an a ,b -alkylene oxide, e.g. ethylene, propylene-1,2 and butylene-1,2 and -2,3 oxides, in the presence of an alkaline catalyst and optionally in the presence of a compound containing one or more reactive hydrogen atoms. The inorganic materials are generally compounds of alkali and alkaline earth metals, particularly potassium and sodium hydroxides. Treatment may be effected at 25 to 150 DEG C., preferably 90 DEG to 110 DEG C., when the polyether is liquid. Water is preferably added before or after the addition of the acid and before the removal of volatile and insoluble materials. A basic material insoluble in the polyether is also preferably added before these removals, optionally in conjunction with a filter aid such as kieselguhr. And the polyether may be treated with an absorbent material, e.g. finely divided carbon, before the final filtration. The examples describe the preparation and purification of polyethers prepared by reacting propylene oxide with diethylene glycol, 1,1,1-trimethylol propane and glycerol respectively. In Example 6, after treatment with adipic acid and kieselguhr, there are added finely divided carbon and 2-(a -methylcyclohexyl)-4,6-dimethyl phenol before removal of volatiles &c. Specification 864,097 is disclaimed.