Oxidation process
US4943358A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1989 |
| Grant date | Jul 24, 1990 |
| Priority date | — |
| Expiry date | Mar 15, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C49/784
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
It is desired to find an alternative way to produce benzophenones or substituted benzophenones which does so selectively and avoids the problems of previous methods that use, for example, large amounts of an aluminium chloride catalyst or nitric acid. In the invention process, a diphenyl methane starting material (DPM) in a hydrophobic phase is oxidized in a photolytic process by contact with an aqueous phase containing greater than 1 mole of HBr and at least 1.5 moles of H.sub.2 O.sub.2, both per mole of DPM, the radiation being capable of dissociating bromine to its radicals, and especially using light of wavelength 600 to 250 nm. Preferably, a reaction temperature of around 50.degree. to 65.degree. C., is used, the organic solvent comprising a suitably boiling chlorinated carbon or hydrocarbon. The H.sub.2 O.sub.2 is introduced progressively into the reaction mixture. The benzophenone product is recovered substantially in the organic phase, whereas most of the bromine/bromide is retained in the aqueous phase which can be re-employed in a subsequent oxidation of DPM, possibly after restoration of the bromide to its initial concentration. In a modification to the process, by suita…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.