azeotrope: a standalone construct

John Wade and Richard William Merriman coined the term azeotropic in 1911 while measuring how water shifts the boiling point of ethyl alcohol, building the word from Greek roots meaning roughly no change on boiling. An azeotrope is a liquid mixture of two or more components whose vapor, at a given pressure, has exactly the same composition as the liquid it rises from, so the mixture boils at a single constant temperature and distills over without any change in composition. Because ordinary distillation separates components by the difference between a liquid and its vapor, an azeotrope is the composition where that difference disappears and simple distillation can go no further: the familiar mixture of about 95.6 percent ethanol and 4.4 percent water by mass is a minimum-boiling azeotrope for this reason. Azeotropes fall into two kinds, minimum-boiling (positive), which boil below every pure component, and maximum-boiling (negative), which boil above them, and large reference compilations such as Horsley's tabulate the compositions and boiling points of many thousands of them.[1][2][3]

Unit

A composition-specific liquid mixture whose boiling vapor equals the liquid in composition, defined at a stated pressure

Recovery means

Not applicable

Measured by

Identified from vapor-liquid equilibrium data, at the point where the vapor and liquid compositions become equal and the mixture boils at a constant temperature for a given pressure