Process for the preparation of trifluoromethylphenols

A process for the preparation of a trifluoromethylphenol or the corresponding alkoxy compound which comprises contacting a halogenobenzotrifluoride of the formula ##STR10## in which X denotes halogen,

• R.sup.1, R.sup.2 and R.sup.3 denote hydrogen, trifluoromethyl or a substituent which promotes the replacement of X by a hydroxyl group and
• Y denotes hydrogen, halogen or alkoxy, at least one of the substituents R.sup.1, R.sup.2 and R.sup.3 representing a trifluoromethyl group and at least one of them representing a substituent which promotes the replacement of the radical X by a hydroxl group,
• with an excess aqueous alkali metal hydroxide in an alcoholic solution in the presence of a quaternary onium salt of the formula ##STR11## in which Z denotes an atom of main group 5 of the periodic system,
• R.sup.4 to R.sup.7 independently of one another denote alkyl , substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, or substituted aryl, of two of the radicals R.sup.4 to R.sup.7, together with the central atom Z which can additionally contain additional hetero-atoms, form a heterocyclic ring, the radicals R.sup.4 to R.sup.7 together containing at least 6 carbon atoms, and A denotes a chloride, bromide or hydroxide anion,
• at a temperature of from 0.degree. to 80.degree. C.