Extractants
In chemistry, the term extraction agent (also called extraction agent ) refers to substances with which a valuable component (extract) is selectively extracted from an extraction material (the extraction residue remains ). The process itself is known as extraction and is a method for separating, extracting or enriching substances. As extraction agent, for example, solvents , supercritical fluids or A d sorbent for physical adsorption or physical extraction or complexing agent for the chemical absorption or chemical extraction is used.
A large number of different extractants are used in chemical processes. Examples: Certain components of a mixture can be extracted with hot water or reaction mixtures from chemical synthesis approaches are occasionally separated using organic solvents (such as hexane or chloroform ); liquefied gases ( supercritical carbon dioxide or butane ) are also used as extraction agents. A disadvantage when using extraction agents is that usually very small amounts of extraction agent remain in the purified products.
Application examples
Natural flavoring substances and flavoring extracts are obtained, among other things, by extraction with solvents . In Germany, in accordance with Section 4 of the Aroma Ordinance (AromV) , solvents contained in the product must be labeled if they are not given to the end user.
The decaffeination of coffee is carried out on an industrial scale on extraction process wherein as extracting agent either dichloromethane , ethyl acetate or supercritical carbon dioxide can be used.
Fractionated edible fats and oils are more likely to be produced by cooling and then separating the higher ( stearins ) from lower ( oleins ) melting fractions, but also with the use of solvents or wetting agents .
In the pharmaceutical industry , water, ethanol , ammonia water , diethyl ether and methanol are used for the production of drug extracts . Example: The active ingredient of the herbal sedative from the valerian root can be obtained with methanol or ethanol.
Individual evidence
- ^ Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, p. 387.
- ↑ Principles for edible fats and oils (PDF; 152 kB).