Process for the continuous preparation of polyglycidyl ethers of polyhydroxy phenols

Claim 1

A method for the continuous preparation of liquid epoxy resins comprising diglycidyl ethers of dihydroxy phenols by reacting a dihydroxy phenol with an epihalohydrin in the presence of an alkali metal hydroxide, which comprises: contacting in a first stage of reaction a dihydroxy phenol with an excess of epihalohydrin in a quantity of from 8 to 15 moles of said epihalohydrin for each mole of said dihydroxy phenol and an aqueous solution of alkali metal hydroxide in a molar ratio of said hydroxide to said dihydroxy phenol not exceeding 2:1, at a pressure of from 1 to 4 atmospheres above atmospheric pressure, at a temperature of from 80° to 140° C and with a residence time of from 20 to 140 minutes; subjecting the reaction products of said first stage to decantation and washing with water, at a pressure of from 1 to 4 atmospheres above atmospheric pressure and at a temperature of from 40° to 140° C and recovering the resulting organic phase; removing the unreacted epihalohydrin from said organic phase by distillation at subatmospheric pressure and recovering as a residue a liquid epoxy resin having a content of hydrolyzable chlorine of from 1 to 6% by weight; dissolving said recovered epoxy resin in an aromatic hydrocarbon or a cycloaliphatic hydrocarbon and contacting in a second stage of reaction the resulting solution with an aqueous solution of alkali metal hydroxide while maintaining an atomic ratio of alkali metal to the hydrolyzable chlorine contained in the resin of from 1:1 to 1.17:1, at a pressure of from 1 to 4 atmospheres above atmospheric pressure, at a temperature of from 80° to 140° C and with a contact time of from 10 to 80 minutes; subjecting the reaction products of said second stage to decantation and washing with water, at a pressure of from 1 to 4 atmospheres above atmospheric pressure and at a temperature of from ambient temperature to 140° C and recovering the resulting separated organic phase; and removing by distillation at subatmospheric pressure the hydrocarbon solvent from said organic phase and recovering a liquid epoxy resin with a content of hydrolyzable chlorine less than 0.02% by weight.

Claim 2

A method for the continuous preparation of liquid epoxy resins comprising diglycidyl ethers of dihydroxy phenols by reacting a dihydroxy phenol with an epihalohydrin in the presence of an alkali metal hydroxide, which comprises: contacting in a first stage of reaction a dihydroxy phenol with an excess of epihalohydrin in a quantity of from 8 to 15 moles of said epihalohydrin for each mole of said dihydroxy phenol and an aqueous solution of alkali metal hydroxide in a molar ratio of said hydroxide to said dihydroxy phenol not exceeding 2:1, at a pressure of from 1 to 4 atmospheres above atmospheric pressure, at a temperature of from 80° to 140° C and with a residence time of from 20 to 140 minutes; subjecting the reaction products of said first stage to decantation and washing with water, at a pressure of from 1 to 4 atmospheres above atmospheric pressure and at a temperature of from 40° to 140° C and recovering the resulting organic phase; removing the unreacted epihalohydrin from said organic phase by distillation at subatmospheric pressure and recovering as a residue a liquid epoxy resin having a content of hydrolyzable chlorine of from 1 to 6% by weight; dissolving said recovered epoxy resin in an aromatic hydrocarbon or a cycloaliphatic hydrocarbon and contacting in a second stage of reaction the resulting solution with an aqueous solution of alkali metal hydroxide while maintaining an atomic ratio of alkali metal to the hydrolyzable chlorine contained in the resin of from 1:1 to 1.17:1, at a pressure of from 1 to 4 atmospheres above atmospheric pressure, at a temperature of from 80° to 140° C and with a contact time of from 10 to 80 minutes; subjecting the reaction products of said second stage to decantation and washing with water, at a pressure of from 1 to 4 atmospheres above atmospheric pressure and at a temperature of from ambient temperature to 140° C and recovering the resulting separated organic phase; and removing by distillation at subatmospheric pressure the hydrocarbon solvent from said organic phase and recovering a liquid epoxy resin with a content of hydrolyzable chlorine less than 0.02% by weight.