Institut Francais Du Pe'trole

Jacques Benzaria

Francois Dawans

Bruno Durif-Varambon

Jean-Bernard Gaillard

An improved method for recovery of alkali metal or alkaline-earth metal terephthalate and of alkylene glycol, from polyalkylene terephthalate, in particular from polyethylene terephthalate (P.E.T.), alkylene glycol, in particular ethylene glycol produced in the form of vapor during the saponification reaction, initiated by the action of intensive kneading of polyalkylene terephthalate and the alkaline reagent at a temperature of 100.degree. to 200.degree. C. The alkylene glycol is recovered in gaseous form by entrainment by an inert gas or by extraction under low pressure. The alkaline terephthalate or alkaline-earth terephthalate is obtained in solid or powder form; it can easily be stored, transported and redissolved, in order to be purified and possibly transformed into terephthalic acid or ester.

Method for recovery of alkali metal or alkaline-earth metal

Production of alkali metal or alkaline-earth metal terephthalate by reaction of an alkali metal or alkaline-earth metal hydroxide with a polyol polyterephthalate, and optional conversion of the terephthalate into terephthalic acid. The reaction is performed without addition of water or in the presence of an amount of water representing at most, by weight, the amount of polyterephthalate. The invention is useful for the treatment of polyol polyterephthalate waste.

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Chambly, France

Jacques Benzaria