Sulphonation of phenols

摘要

A process for the preparation of sulphonated phenols of general formula (I) where R₁ is hydrogen, a C₁-C₂₀ alkyl group which is unsubstituted or substituted by halogen, cyano, hydroxyl, C₁-C₂₀ alkoxy, C₂-C₂₀ alkoxycarbonyl, acyloxy and/or phenyl which is unsubstituted or substituted by C₁-C₄ alkyl, C₁-C₄ alkoxy and/or halogen, R₂ is hydrogen, C₁-C₂₀ alkyl or benzoyl of general formula (II) where R₃ and R₄ independently of one another are each hydrogen, halogen, C₁-C₁₂ alkyl, C₁-C₁₂ alkoxy, C₁-C₄ haloalkyl, C₃-C₈ cycloalkyl, C₄-C₁₂ cycloalkylalkyl, cyano, hydroxyl, or hydroxyethyl or are each phenoxy, C₇-C₁₀ phenylalkyl or phenyl which is unsubstituted or substituted by C₁-C₄ alkyl, C₁-C₄ alkoxy and/or halogen, and R₅ is hydrogen or the group SO₃X where X can be hydrogen, a monovalent metal or a group -N(R₆)₃, where each of the three radicals R₆ can be independently of one another hydrogen, C₁-C₆ alkyl or C₁-C₆ hydroxy alkyl, which process comprises reacting a phenol of general formula (III) where R₁ and R₂ are as defined above, with a halosulphonic acid in a solvent which is a mixture of a C₅-C₁₀ aliphatic or cycloaliphatic hydrocarbon and a dialkyl carbonate of general formula (IV) R₇-O-CO-O-R₈ where R₇ and R₈ each represent independently a C₁-C₄ alkyl group