Method and apparatus for controlling the manufacture of terephthalic acid to control the level and variability of the contaminant content and the optical density
US4835307A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1984 |
| Grant date | May 30, 1989 |
| Priority date | — |
| Expiry date | Dec 13, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/265
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The method and apparatus for manufacturing terephthalic acid (TA) are capable of producing TA having a closely controlled, desired amount of contaminant, 4-carboxy-benazldehyde (4-CBA), therein and/or a closely controlled optical density. In the method, a feed of para-xylene or similar feedstock mixed with catalyst components and solvent system is fed to a reactor stage comprising one or more reactors with oxygen for carrying out an exothermic oxidation reaction in the reactor stage, and an output slurry from the reactor stage is fed with oxygen to a first crystallizer of a crystallizing stage. The method comprises the steps of: determining empirical relationships between (1) the desired level of contaminant in the TA output product from the crystallizing stage and the oxygen uptake in the first crystallizer and (2) the oxygen uptake in the first crystallizer and the CO.sub.2 in the vent gas from the reactor stage; monitoring the CO.sub.2 in the vent gas from the reactor stage; and, adjusting operating variables of the reactor stage within minimum and maximum constraints thereof to adjust the reactor vent CO.sub.2 to a desired level. Also, the method includes the steps of: determin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.