Process for preventing blackening of phthalic acid
US4214100A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 1977 |
| Grant date | Jul 22, 1980 |
| Priority date | — |
| Expiry date | Dec 5, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/265
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
In the production of phthalic acid by oxidizing, in a liquid phase, tolualdehyde with molecular oxygen or a gas containing the molecular oxygen in the presence of heavy metal salt containing a Mn salt, especially both Mn and Co salts, and a bromine compound, using a lower aliphatic monocarboxylic acid as a reaction solvent, a blackening of phthalic acid is effectively prevented by conducting the oxidation of tolualdehyde in the presence of an alkylbenzene in an amount satisfying the following formula (1); EQU M.ltoreq.-0.15A.sup.2 +15A+40 (1) wherein M is a Mn atom concentration in.ppm by weight on the basis of the reaction solution, and A is an amount in % by weight of the alkylbenzene added on the basis of the total of tolualdehyde and said alkylbenzene, and is in a range of from more than 0 to 50 inclusive.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.