Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1994-10-05
1995-12-05
Dees, Jos' G.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
562485, 568868, C07C 6760
Patent
active
054731020
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: depolymerization of polyester resin in a molten polyester resin containing solvent with superheated stem, and vaporization of the aromatic carboxylic acid and other volatile products of hydrolysis to obtain a vaporized mixture containing aromatic acid, dihydric alcohol, other volatile products of hydrolysis, and water. This vapor mixture is, advantageously, substantially free of less volatile and non-volatile impurities including metals, and many colored and color causing compounds, which are, typically, found in post-consumer polyester resins.
Crude acid is, optionally, purified by 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 rage of from about 95 to about 100, an a*-value in a rage of from about -1 to about +1, and a b*-value in a range of from about 0.5 to about 2.
REFERENCES:
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patent: 4355175 (1982-10-01), Pusztaszeri
patent: 4605762 (1986-08-01), Mandoki
patent: 4620032 (1986-10-01), Doerr
patent: 5051528 (1991-09-01), Naujokas et al.
H. S. Bryant et al., "Mobil's Process for TPA," Chemical Engineer Progress (vol. 67, No. 9), Sep. 1971, pp. 69-75.
Danawala Kalpana
Johnson Floyd
Rosen Bruce I.
Sikkenga David L.
Amoco Corporation
Barts Samuel
Dees Jos' G.
Nemo Thomas E.
Oliver Wallace L.
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