What is "fractionation"

fractionation \frac`tion*a"tion\ n. the act or process of separating a mixture into portions of different composition, as in distillation or fractional crystallization.

Syn: fractional process.

2. (Petroleum industry) Separation of crude oil into components of differing composition by fractional distillation.

n. 1 (context chemistry English) A separation process in which a certain quantity of a mixture is divided up into smaller quantities (fractions) in which the composition changes according to a gradient. 2 (context cryptography English) A preliminary stage of encryption that divides each plaintext symbol into several ciphertext symbols.

1. n. a process that uses heat to separate a substance into its components [syn: fractional process]

2. separation into portions

Fractionation is a separation process in which a certain quantity of a mixture (gas, solid, liquid, enzymes, suspension, or isotope) is divided during a phase transition, into a number of smaller quantities ( fractions) in which the composition varies according to a gradient. Fractions are collected based on differences in a specific property of the individual components. A common trait in fractionations is the need to find an optimum between the amount of fractions collected and the desired purity in each fraction. Fractionation makes it possible to isolate more than two components in a mixture in a single run. This property sets it apart from other separation techniques.

Fractionation is widely employed in many branches of science and technology. Mixtures of liquids and gases are separated by fractional distillation by difference in boiling point. Fractionation of components also takes place in column chromatography by a difference in affinity between stationary phase and the mobile phase. In fractional crystallization and fractional freezing, chemical substances are fractionated based on difference in solubility at a given temperature. In cell fractionation, cell components are separated by difference in mass.