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US 7,888,530 B2Granted
Optimized production of aromatic dicarboxylic acids
AssigneeEastman Chemical Company
InventorsRobert Lin, Marcel de Vreede
Life of this patent
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Abstract
Disclosed is an optimized process and apparatus for more efficiently producing aromatic dicarboxylic acids (e.g., terephthalic acid). In one embodiment the process/apparatus reduces costs by recovering and purifying residual terephthalic acid present in the liquid phase of an initial oxidation slurry. In another embodiment the process apparatus reduces costs associated with hydrogenation by forming a final composite product containing unhydrogenated acid particles.
Claims15
A process comprising:
- (a) providing a slurry comprising a solid phase and a liquid phase comprising a mother liquor, wherein said solid phase contains a first quantity of terephthalic acid, wherein said liquid phase contains a second quantity of terephthalic acid;
- (b) subjecting at least a portion of said first quantity of terephthalic acid to oxidation treatment to thereby produce oxidation-treated terephthalic acid;
- wherein said oxidation-treated terephthalic acid has a b* value of about 3.5 to about 10 and a 4-carboxybenzaldehyde (4-CBA) and para-toluic acid (p-TAc) content totaling greater than 700 ppmw;
- and
- (c) subjecting at least a portion of said mother liquor containing said second quantity of said terephthalic acid to evaporation treatment to form a concentrated slurry having more than about 10 weight % solid terephthalic acid particles, and subsequently subjecting said second quantity of terephthalic acid to hydrogenation treatment to thereby produce hydrogenation-treated terephthalic acid;
- wherein said hydrogenation-treated terephthalic acid has a b* value of less than 3.0 and a 4-CBA and p-TAc content totaling less than 700 ppmw;
- and;
- (d) combining at least a portion of said oxidation-treated terephthalic acid with at least a portion of said hydrogenation-treated terephthalic acid to produce a final composite acid suitable for use in the manufacture of polyesters;
- wherein the ratio of the amount of said oxygenation-treated terephthalic acid to said hydrogenation-treated terephthalic acid combined with one another is in the a range of from about 10:1 to about 1,000:1 by weight;
- wherein said process further comprises recovering solid particles of said second quantity of terephthalic acid prior to said hydrogenation treatment of step (c).
7 more elements
Dependencies are inferred from the claim text.