Process for the recovery of terephthalic acid and ethylene glycol from poly(ethylene terephthalate)
US5413681A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 1993 |
| Grant date | May 9, 1995 |
| Priority date | — |
| Expiry date | Nov 15, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S203/17
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process useful for the recovery of terephthalic acid and ethylene glycol from poly(ethylene terephthalate) or its copolymers. The process is economical, beneficial to the environment and provides polymer grade terephthalic acid and ethylene glycol from post-consumer resin. The process is a six-step process including: (1) contacting a resin containing poly(ethylene terephthalate) with water at elevated temperature and pressure, (2) cooling the resulting mixture to provide a solid portion containing terephthalic acid and a liquid portion containing ethylene glycol, (3) recovery of the ethylene glycol from the liquid portion by distillation, (4) recovery of the terephthalic acid by heating the solid portion in the presence of water vapor at elevated temperature to produce a vapor containing terephthalic acid and water, (5) cooling terephthalic acid water vapor mixture to a temperature below the dew point of terephthalic acid and (6) collecting the polymer grade terephthalic acid. The polymer grade terephthalic acid and ethylene glycol provided by this process can be used to make high quality terephthalate homopolymers or copolymers for applications including clear bottles and fibers…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.