Process for recovery of alkali metal or alkali earth metal terephtalate and alkylene glycol from alkylene polyterephtalates

摘要

A description is given of an improved process for the recovery of alkali metal or alkaline-earth metal terephthalate and alkylene glycol from poly(alkylene terephthalate), in particular from poly(ethylene terephthalate) (P.E.T.), the alkylene glycol, in particular ethylene glycol, being produced in the vapour form during the saponification reaction, initiated under the action of intense mixing of the mixture of the poly(alkylene terephthalate) and of the alkaline reactant at a temperature of 100@ to 200@C. The alkylene glycol is recovered in the gas form by entraining with an inert gas or by extraction under reduced pressure. The alkali metal or alkaline-earth metal terephthalate is obtained in the solid and powdery form; it can be easily stored, transported and redissolved, in order to purified and then optionally converted to terephthalic acid or to ester.