Enriched terephthalic acid composition
View Patent ↗A process is provided for producing an enriched carboxylic acid compositions produced by contacting composition comprising a carboxylic acid with an enrichment feed in an enrichment zone to form an enriched carboxylic acid composition. This invention also relates to a process and the resulting compositions for removing catalyst from a carboxylic acid composition to produce a post catalyst removal composition.
1. A terephthalic acid composition comprising:
(1) terephthalic acid in an amount greater than 90 percent by weight;
(2) (a) 4-carboxybenzaldehyde in an amount ranging from 1 ppm to 1000 ppm; or
(b) p-toluic acid in an amount ranging from 1 ppm to 1000 ppm; or both (2) (a) and (2) (b); and
(3) at least two of the following:
(a) isophthalic acid in an amount ranging from 50 ppm to 2000 ppm;
(b) trimellitic acid in an amount ranging from 140 ppm to 1000 ppm;
(c) 4,4′-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm;
(d) phthalic acid in an amount ranging from 20 ppm to 1000 ppm;
(e) 4-hydroxybenzoic acid in an amount ranging from 3 ppm to 1000 ppm;
(f) 4-hydroxymethylbenzoic acid in an amount ranging from 40 ppm to 200 ppm; and
(g) benzoic acid in an amount ranging from 50 ppm to 500 ppm;
(4) and at least one of the following present in an amount not greater than 0.5 wt %
antimony catalysts, titanium catalysts, dyes, pigments, reheat agents, antioxidants, thermal stabilizers, UV stabilizers, coupling or chain-extending agents, end-capping agents, telechelic modifiers, acetaldehyde reducing agents, agents to reduce formation of diethylene glycol (DEG), titanium dioxide, and optical brightener.
2. The terephthalic acid composition of claim 1 wherein said composition comprises cyclohexanedimethanol (CHDM).
3. The terephthalic acid composition of claim 1 wherein said composition comprises at least one antimony catalyst.
4. The terephthalic acid composition of claim 1 wherein said composition comprises at least one titanium catalyst.
5. The terephthalic acid composition of claim 1 wherein said composition comprises at least one dye or pigment.
6. The terephthalic acid composition of claim 1 wherein said composition comprises at least one reheat agent.
7. The terephthalic acid composition of claim 1 wherein said composition comprises at least one antioxidant.
8. The terephthalic acid composition of claim 1 wherein said composition comprises at least one thermal stabilizer or UV stabilizer.
9. The terephthalic acid composition of claim 1 wherein said composition comprises at least one coupling or chain-extending agent, end-capping agent or a telechelic modifier.
10. The terephthalic acid composition of claim 1 wherein said composition comprises at least one acetaldehyde reducing agent.
11. The terephthalic acid composition of claim 1 wherein said composition comprises at least one agents to reduce formation of diethylene glycol (DEG).
12. The terephthalic acid composition of claim 1 wherein said composition comprises titanium dioxide.
13. The terephthalic acid composition of claim 1 wherein said composition comprises at least one optical brightener added in a process for the manufacture of terephthalic acid.