liquid-liquid extraction

Question 1

intro

Answer 1

 It is also called as solvent extraction and partitioning.
 In this process solution of substance is brought into contact with first solvent.

 Portioning of drug between two immiscible solvents (aqueous and organic) is the principal of liquid-
liquid extraction.

 This distribution depends upon the hydrophilicity or hydrophobicity of the material.
 pH also plays an important role when the polar group is ionized.
 Usually two, three, or four extractions of the aqueous layer with an organic solvent are carried out in
sequence in order to remove as much of the desired product from the aqueous layer as possible.
 The greater the number of small extractions, the greater the quantity of solute removed.
 However, for maximum efficiency the rule of thumb is to extract three times with 1/3 volume.

Question 2

factors

Answer 2

 Higher the partition coefficient higher will be the extraction efficiency.
 Lower interfacial tension will increase extraction rates.
 Adsorbed impurities on interface retard the transfer of solute.

Question 3

1. Dispersive Liquid–Liquid Microextraction (DLLME):

Answer 3

 A process used to extract small amounts of organic compounds from water samples.
 This process is done by injecting small amounts of an appropriate extraction solvent (C2Cl4) and a
disperser solvent (acetone) into the aqueous solution
 The resulting solution is then centrifuged to separate the organic and aqueous layers.
 This process is useful in extraction organic compounds such as organochloride and organophsophorus
pesticides, as well as substituted benzene compounds from water samples..

Question 4

direct organic extraction

Answer 4

 This process is done by mixing partially organic soluble samples in organic solvent (toluene, benzene
and xylene), the organic soluble compounds will dissolve into the solvent and can be separated using
a separatory funnel.
 This process is valuable in the extraction of proteins and specifically phosphoprotein and
phosphopeptide phosphatases.

Question 5

applications

Answer 5

 Major applications exist in the biochemical or pharmaceutical industry, where emphasis is on the
separation of antibiotics and protein recovery.
 In the inorganic chemical industry, they are used to recover high-boiling components such as
phosphoric acid, boric acid, and sodium hydroxide from aqueous solutions.