Some factors influencing the solubilities of amine sulphates

The relationship between the molecular structures of amines and the solubilities of their sulphates has been examined with the object of finding a better reagent than benzidine for the determination of sulphate. It has been established that the two aromatic rings must have a tendency to be coplanar and collinear, if the sulphate solubility is to be low. With the help of this theory, 4 : 4'-diaminotolane sulphate has been found to be less soluble than bcnzidine sulphate.