Patent ID: 7528271

Claim:
A process for the preparation of 1,4-benzoquiones of formula (II) wherein R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of branched or unbranched C 1 -C 6 alkyl, phenyl and benzyl, wherein phenyl and benzyl is optionally substituted by one or more substituent independently selected from the group consisting of C 1 -C 6 alkyl and halogen, and wherein C 1 -C 6 alkyl is optionally substituted with one or more halogen substituents, and wherein R2 and R3 together can form a C 1 -C 6 -alkylene radical, optionally substituted by one or more substituents independently selected from the group comprising C 1 -C 6 , benzyl, phenyl and halogen, by reacting a compound of formula (III) wherein R 1 , R 2 , R 3 and R 4 are as defined above, with a peroxide oxidant, in an acidic solvent, with the presence of an acid catalyst which is para-toluenesulfonic acid, wherein the process does not involve a Fenton type reagent.