×

Process for the oxidative purification of terephthalic acid

  • US 7,074,954 B2
  • Filed: 08/21/2003
  • Issued: 07/11/2006
  • Est. Priority Date: 12/09/2002
  • Status: Active Grant
First Claim
Patent Images

1. A process to produce a purified carboxylic acid slurry composition said process comprising:

  • (a) removing impurities from a crude carboxylic acid slurry composition in a solid liquid displacement zone to form a slurry composition;

    (b) oxidizing said slurry composition at a temperature of about 190°

    C. to about 280°

    C. in a staged oxidation zone to form a staged oxidation composition;

    (c) crystallizing said staged oxidation composition in a crystallization zone to form a crystallized composition; and

    (d) removing in a subsequent solid liquid displacement zone impurities from said crystallized composition to from said purified carboxylic acid slurry composition;

    wherein said impurities comprise 4-carboxybenzaldehyde, trimellitic acid, or 2,6-dicarboxyfluorenone; and

    wherein said subsequent solid liquid displacement zone comprises at least one solid liquid separator that is operated at a temperature between 110°

    C. to 200°

    C.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×