Process for preparing fluorinated benzyl alcohols and fluorinated benzaldehydes

摘要

Fluorinated benzaldehydes are obtainable in a simple and inexpensive manner and in significantly improved yields when chlorinated benzaldehydes are reacted with alkali metal fluorides at temperatures in the range from about 130 to 200 DEG C. in the presence of less than about 2 mol % of quaternary phosphonium salts, based on chlorine atoms to be replaced, at initial concentrations of more than 2.5 mol of the chlorinated benzaldehydes per kg of dipolar aprotic solvent. Fluorinated benzaldehydes obtained in this way can advantageously be hydrogenated with hydrogen in the presence of noble metal catalysts to give fluorinated benzyl alcohols.