The reaction of phenol with formaldehyde. III. selective hydroxymethylation of phenols at the ortho‐position

The effect of chelating substances on the orientation of hydroxymethyl groups in the reaction of phenol with formaldehyde is described. It is found that when using hydroxides of the transition metals, Cu, Cr, Mn, Ni and Co, in aequous solution at pH = 4‐5, hydroxymethylation occurs mainly at the ortho‐position. Similar results were obtained with boric acid in benzene solution. Chelate formation in the transition state for ortho‐substitution is supposed to be the basic reason for the selective catalysis.