The Mechanism of the Alkaline Fusion of Diphenylsulfone

Diphenylsulfone-1-14C was treated with fused potassium hydroxide at 300°C for 7 hr. in a sealed metal tube. The yield of phenol, as determined by the isotope dilution technique, was found to be almost quantitative. The distribution of 14C in the resulting phenol was determined by degradating it by the usual method. Practically all the activity of 14C in the phenol was found at the position 1, which corresponded to the originally-labeled position in the diphenylsulfone-1-14C used. This indicates that the mechanism of the alkaline fusion of diphenylsulfone proceeds thruogh a simple SN2-type mechanism, not the elimination-addition mechanism.