RECTIFICATION (late lat. gestificatio - straightening, correction) — division of mixes of liquids on fractions or purification of individual liquid of the impurity dissolved in it by distillation (distillation); it is applied in laboratory and pharmacological practice, and also in pharmaceutical industry to allocation of components from complex mixtures of mutually soluble liquids (e.g., petroleum hydrocarbons, oxidates of hydrocarbons etc.), to purification of individual liquids (e.g., alcohol, etc.).
Equilibrium distillation did not possible to reach full unmixing of liquids usually therefore resort to repeated distillations (see). Such way P. is labor-consuming, connected with loss of substance and does not lead to desirable results in of those cases when mix consists of liquids with close temperatures of boiling.
At R. vapors of the divided liquids pass via special devices, so-called rectification columns. Vapors of the boiling liquid, air cooled, are condensed in an upper part of a column, and condensate flows down down. In the course of R. components of liquid with lower temperature of boiling pass into steam, and with more high temperature of boiling — from steam in liquid. Such process repeats repeatedly on all volume of the rectification column. Liquid flows down in the receiver, and steam moves up and, exempted from impurity, reaches the refrigerator dephlegmator. The liquids which are formulation components come to the receiver one by one as increase in their temperatures of boiling.
The researcher changes the receiver every time at change of temperature of vapors and receives pure components of mixes.
Bibliography: Bagaturov S.A. Bases of the theory and calculation of distillation and rectification, M., 1974, bibliogr.; Voskresensky P. I. Technology of laboratory works, M., 1973; Heats V. T. and Serafimov L. A. Physical and chemical bases of distillation and rectification, JI., 1975, bibliogr.
V. K. Shtal.