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US 12,590,058 B2Granted
Photooxidation of 2,4,6-trimethylphenol
AssigneesDsm IP Assets B.V., UniversitäT Basel
InventorsWerner Bonrath, Thomas Buchholz, Thomas Netscher, Jan Schuetz, Christof Sparr
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Abstract
The present invention relates to the photooxidation of 2,4,6-trimethyl-phenol to yield 4-hydroperoxy-2,4,6-trimethylcyclohexa-2,5-dien-1-one using methylene blue as photosensitizer in a solvent mixture of water and alcohols using light of the high wavelength range of the visible spectrum. This process allows 5 obtaining 4-hydroxy-2,4,6-trimethylcyclohexa-2,5-dien-1-one and 2,3,5-trimethyl-hydroquinone in high yields and selectivity from 2,4,6-trimethylphenol.
Claims22
A process for manufacturing a compound of formula (I) from a compound of formula (II):
- wherein the process comprises:
- conducting photooxidation of the compound of formula (II) using oxygen and a photosensitizer of the formula (III):
- wherein R8, R8′, R8″ and R8′″ independently from each other represent either a H, or a C1-4 alkyl group;
- or
- wherein R8 and R8′ and/or R8″ and R8′″ form together with N a five or six membered ring;
- with the proviso that at least one of the residues R8, R8′, R8″ and R8′″ is different from H;
- and
- X− represents an anion;
- in a solvent mixture of water and at least one C1-8 alkanol or at least one C2-4 alkylene diol;
- and wherein
- the photooxidation is conducted using light which has a peak wavelength (λmax) in a spectrum of the light which is in a range of between 580 and 780 nm.
8 more elements
Dependencies are inferred from the claim text.