The sulfonation of diphenyl ether and its derivatives has been very little investigated. Hoffmeister2 found that the action of concentrated sulfuric acid on diphenyl ether gave a disulfonic acid, but the positions occupied by the acid groups were not determined. The same acid3 had been made previously but was considered to be a derivative of diphenyl. It has recently been found4 that aminosulfonic acid sulfonates diphenyl ether to the ...
