Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1987-06-04
1988-11-01
Lone, Werren B.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
562412, 562414, 562485, 562486, C07C 5142
Patent
active
047821817
ABSTRACT:
A process for producing fiber grade terephthalic acid is disclosed. In this process impurities having high molecular weight are eliminated by hydrogenation comprising the following steps: (a) treating an aqueous solution containing at least about 1 percent of said impure terephthalic acid with hydrogen at a temperature in the range of about 300.degree. F. to about 450.degree. F. and at a pressure sufficient to maintain the solution in the liquid phase in the presence of a supported or unsupported metallic Group VIII noble metal catalyst wherein both the metal and support components are insoluble in the solution at the temperature and at a hydrogen partial pressure of from about 30 to about 300 pounds per square inch; (b) separating the treated solution from the catalyst; (c) crystallizing terephthalic acid from the separated solution while retaining impurities and the reduced aromatic compounds dissolved in the resulting mother liquor at a temperature in the range of about 100.degree. F. to about 450.degree. F.; and (d) separating the mother liquor as a liquid phase containing dissolved impurities and reduction products from said crystals while continuing to maintain a temperature in the range of about 100.degree. F. to about 450.degree. F. whereby purified crystals of fiber grade terephthalic acid are recovered. Purified terephthalic acid is useful as a starting material in the manufacture of polyethylene terephthalate which is the principal polymer for polyester fibers, films, and resins for bottles.
REFERENCES:
patent: 3584039 (1971-06-01), Meyer
patent: 3726915 (1973-04-01), Pohlmann
patent: 4405809 (1983-09-01), Stech et al.
patent: 4626598 (1986-12-01), Packer et al.
Amoco Corporation
Blumberg Gunar J.
Clarke Vera C.
Lone Werren B.
Magidson William H.
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