Sidney Young

Sidney Young (1857-1937) was a pioneer in the separation and specification of pure organic compounds, and developed crucial thermodynamic relationships for solids and liquids. He examined in great detail the P-T-V phase space of pure substances and proved that below their triple point ice and other substances sublime but will not melt even under heating. In addition, he demonstrated that the mean linear rectilinear law of Cailletet and Mathias was valid only for temperatures above the boiling point of the substance. Young studied the distillation of petroleum and its fractions and separated for the first time n-pentane, n-hexane, and isopentane. Of particular significance is his discovery of the ternary minimum boiling temperature azeotrope of benzene + water + ethanol, which led to the industrial manufacture of absolute alcohol.