fractionation

chemistry

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June 26, 2026

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Fractionation is a process used to separate mixtures based on differences in their physical properties, most commonly boiling points. This technique is fundamental in chemistry and industry, particularly in separating liquids with varying volatilities.

Distillation

Distillation involves boiling a liquid to convert it into vapor, which is then condensed back into a liquid form and collected separately. This method is effective for separating liquids from non-volatile solids or liquids with significantly different boiling points. For mixtures with closely boiling components, fractional distillation is employed. This involves repeated condensation and vaporization within a column, allowing for a more precise separation. A prime example is in petroleum refining, where crude oil is separated into fractions like gasoline and kerosene.123

Isotopic Fractionation

Isotopic fractionation exploits subtle differences in mass between isotopes of an element, leading to slight variations in chemical reaction rates or physical processes. This can result in the enrichment of one isotope over another. For instance, during photosynthesis, the lighter isotope of carbon (carbon-12) is preferentially used, leading to its enrichment in organic matter. This principle is also applied in separating isotopes of elements like uranium for nuclear applications.4

Foam Fractionation

Foam fractionation utilizes foams to achieve separations based on adsorption at gas-liquid interfaces. When gas is bubbled through a solution containing substances like soaps or detergents, a foam forms, concentrating these substances. This method is also used in flotation, where particles are carried to the surface by foam bubbles, a process crucial in mineral processing.5

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chemical analysis
Distillation
…volatile liquid in the first fractions and the less volatile components in the later fractions. The analyte typically goes through several vaporization-condensation steps prior to arriving at the condenser.
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…volatile liquid in the first fractions and the less volatile components in the later fractions. The analyte typically goes through several vaporization-condensation steps prior to arriving at the condenser.
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rare-earth element
Discovery and history
…pure rare earth, usually by fractional crystallization, which makes use of the slight differences of the solubility of a rare-earth salt in an aqueous solution compared with that of a neighbouring lanthanide element.
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…pure rare earth, usually by fractional crystallization, which makes use of the slight differences of the solubility of a rare-earth salt in an aqueous solution compared with that of a neighbouring lanthanide element.
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zone melting
Principles of zone refining.
…the long-known technique of repeated fractional crystallizations. Although this technique was employed by the Curies to isolate radium it never became widely used because it entailed a lengthy and troublesome sequence of operations: partial freezing, separation of the crystals from the unfrozen liquid, remelting, and recombining with other fractions.
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…the long-known technique of repeated fractional crystallizations. Although this technique was employed by the Curies to isolate radium it never became widely used because it entailed a lengthy and troublesome sequence of operations: partial freezing, separation of the crystals from the unfrozen liquid, remelting, and recombining with other fractions.
Read More