Extraction (chemistry)

From Wikipedia, the free encyclopedia
Jump to: navigation, search

Extraction in chemistry is a separation process consisting in the separation of a substance from a matrix. It may refer to Liquid-liquid extraction, and Solid phase extraction.

Other techniques include Supercritical carbon dioxide extraction, ultrasonic extraction, heat reflux extraction, microwave-assisted extraction, DIC (instant controlled pressure drop) and perstraction.[1][2]

Extractions use two immiscible phases to separate a solute from one phase into the other. The distribution of a solute between two phases is an equilibrium condition described by partition theory. Boiling tea leaves in water extracts the tannins, theobromine, and caffeine out of the leaves and into the water. More typical lab extractions are of organic compounds out of an aqueous phase and into an organic phase.

Common extractants are arranged from ethyl acetate to water (ethyl acetate < acetone < ethanol < methanol < acetone:water (7:3) < ethanol:water (8:2) < methanol:water (8:2) < water) in increasing order of polarity according to the Hildebrand solubility parameter.

The extract can be put back to dried form using a centrifugal evaporator or a freeze-drier.

See also[edit]

References[edit]

  1. ^ Microwave-assisted extraction of tea polyphenols and tea caffeine from green tea leaves. Xuejun Pan, Guoguang Niu and Huizhou Liu, Chemical Engineering and Processing, Volume 42, Issue 2, February 2003, Pages 129-133 doi:10.1016/S0255-2701(02)00037-5
  2. ^ LUQUE, R., CAMPELO, J. and CLARK, J., eds, 2011. Handbook of Biofuels Production - Processes and Technologies. Woodhead Publishing.