Process for recovery of aromatic acid from waste polyester resin
US5414113A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 1993 |
| Grant date | May 9, 1995 |
| Priority date | — |
| Expiry date | Oct 18, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/09
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Processes are disclosed for recovery and purification of dibasic aromatic acids from waste polyester film, fiber, bottles, manufacturing residues, and other manufactured articles. The processes comprises: depolymerizing polyester resin in a solvent under conditions suitable for hydrolysis of ester bonds to obtain a mixture containing a solution of aromatic acid and impurities consisting of alcohol and/or other components of the resin; burning impurities in a liquid-phase oxidation with an oxygen-containing gas in the presence of an oxidation catalyst at elevated pressures and temperatures, to obtain an oxidation product containing the desired aromatic acid; and crystallizing and separating from the oxidation system a resulting crude dibasic aromatic acid. Crude acid is, optionally, hydrogenated in an aqueous solution at elevated temperatures and pressures in the presence of hydrogen and an insoluble metal-containing catalyst, which is thereupon separated from the aqueous solution, and purified dibasic aromatic acid recovered by crystallization and mechanical separation from the aqueous solution. Purified terephthalic acid has, typically, a L*-value in a range of from about 95 to ab…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.