Method for recovery of alkali metal or alkaline-earth metal terephthalate and of alkylene glycol from polyethylene terephthalates
US5545746A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1995 |
| Grant date | Aug 13, 1996 |
| Priority date | — |
| Expiry date | Jan 3, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/41
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.