GB897744A - Improvements in or modifications of a process for the production of a low molecular weight glycidyl polyether of a polyhydric phenol - Google Patents

Abstract

Glycidyl polyethers of a polyhydric phenol, having more than one glycidyl group and having a molecular weight of less than 500, are made by condensing the polyhydric phenol in the presence of 1 to 10 mol per cent, based on the polyhydric phenol, of a tertiary amine or quaternary ammonium compound at an elevated temperature with an excess of epichlorohydrin to form the chlorohydrin ether, which is then dehydrochlorinated by means of an alkaline material to form the glycidyl polyether, which is subsequently washed free from alkali, the molar ratio of the epichlorohydrin to the polyhydric phenol used being at least 4, the reaction mixture being freed from the excess of the epichlorohydrin after the condensation. Dihydric phenols such as resorcinol, hydroquinone, 4, 41 - dihydroxy - diphenyl, bis(hydroxyphenyl)methane and 2,2-bis(41 hydroxyphenyl)propane. The catalyst is preferably used in 10 to 40% by weight aqueous solution. It is preferred to keep the amount of water in the reaction mixture below 25% based on the phenol. Water may be removed by azeotropic distillation with the epichlorohydrin, the azeotrope separating into two phases and the epichlorohydrin being returned to the reactor. Solvents such as benzene, toluene, acetone, methylethyl ketone, diethyl ether, dioxane and dichlorohydrin may be present. The molar ratio of epichlorohydrin to phenol is at least 4, and preferably in the range from 6 to 15. The preferred condensation temperatures are in the range 90 DEG C. to 110 DEG C., the reaction time being generally from 1-5 hours. Preferably the reaction conditions are so chosen that not more than 1% of the polyhydric phenol remains unreacted. The condensation may be effected continuously in an extended tubular reactor. Dichlorohydrin and excess epichlorohydrin may be removed by distillation and the catalyst may be removed by water washing. Washing and the subsequent dehydrochlorination are preferably effected at 60 DEG C. to 100 DEG C. 5% aqueous sodium hydroxide may be used as dehydrochlorinating agent, preferably using 10% to 100% by weight excess based on chlorine in the chlorohydrin ether. The dehydrochlorination is followed by washing to remove the alkali. Detailed examples are given. Specification 843,575 is referred to.