Apparatus for iso- or terephthalic acid production in and recovery from benzoic acid-water solvent system
US4185073A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1977 |
| Grant date | Jan 22, 1980 |
| Priority date | — |
| Expiry date | Jul 26, 1997 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J2219/185
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Continuous production of iso- or terephthalic acid in a stirred reaction zone by catalytic air oxidation of m- or p-xylene in the presence of a benzoic acid-water liquid solvent system at constant gauge pressure within the range of 7 to 21 kg/cm.sup.2 wherein oxidation temperature within the range of 175.degree. to 235.degree. C. is maintained substantially constant by the novel control thereof by only varying the flow rate of water condensate reflux to the oxidation zone. The invention further pertains to novel means for achieving such temperature control. Also, the present invention relates to a novel continuous recovery of the phthalic acid product from the fluid effluent of said continuous process by a process wherein crystalline phthalic acid product is separated from essentially water-free benzoic acid mother liquor; the crystalline product is successively washed with liquid benzoic acid and the corresponding xylene; the washed product is dried; and the water removed from said fluid effluent, the benzoic acid and xylene wash liquors, xylene recovered from product drying, and a major proportion of the benzoic acid mother liquor are charged to the oxidation process. The inventi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.