Process for the preparation of hydroxybenzaldehydes

摘要

In a Reimer-Tiemann reaction for the preparation of a mixture of two hydroxybenzaldehydes (i.e., salicylaldehyde and p-hydroxybenzaldehyde) by reacting phenol with chloroform and an aqueous alkali solution in a heterogeneous system, the two hydroxybenzaldehydes can be prepared in a controlled formation ratio, yield and reaction rate depending upon the conditions used when the reaction is carried out in the presence of a phase transfer catalyst selected from the group consisting of a cationic type phase transfer catalyst, an amphoteric type phase transfer catalyst and an anionic type phase transfer catalyst.