The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 1995
Filed:
Oct. 18, 1993
Jeffrey L Broeker, Naperville, IL (US);
John A Macek, Naperville, IL (US);
Mossman: Allen B, Wheaton, IL (US);
Bruce I Rosen, Morton Grove, IL (US);
Thomas M Bartos, Naperville, IL (US);
Amoco Corporation, Chicago, IL (US);
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 about 100, an a*-value in a range of from about -1 to about +1, and a b*-value in a range of from about 0.5 to about 2.