Solvent Extraction, Introduction, Principle and features.

Solvent extraction Introduction, Principle and Features. 

Introduction:

There are many methods of analysis which involves separation of components of mixture, their purification and their estimation. 

These two terms one is Separation and other is purification having different conditions. 

Separation starts with material composed of large amount of one constituent and small amount of other constituents. In this process all the constituents obtained in the pure form. 

Purification involves small amount of other constituents is removed to get the large constituents in pure form . 

Methods used for separation of mixture of constituents. 

1.Physical Method. 

2.Chemical Method. 

1.In physical method, the advantage of the differences in physical properties of the constituents is taken. 

For example. Adsorption , Solubility, etc. 

2.In chemical method, the advantage of the differences in chemical properties of the constituents is taken. 

For example. Precipitation. 

Principle of Solvent Extraction: 

Solvent extraction is used for the separation of components of the mixture. 

Principle: 

A solute can be distributed itself between the two immiscible solvent like benzene, chloroform, carbon tetrachloride.

There are generally two types of compounds. 

Ionic and covalent compounds. 

Ionic compounds are insoluble in non polar solvents which having high dielectric constant. 

Therefore the extraction of the ion from its aqueous solution into an immiscible organic solvents can be done if the ion forms the uncharged species. 

Example: Chelated neutral complexes or an ion pair . [H+] [ AuCl4-] and H+[FeCl4]-

These principles are used in solvent extraction. 

The technique is called Liquid- Liquid Extraction. 

Apparatus used for Solvent Extraction is Separatory funnel . 

Separatory funnel is made up of glass and having stop cock and stopper. 

Features of Solvent Extraction: 

1.It is simple in operation and easy to carry out. 

2.There is no need of any sophisticated Equipments and instruments. 

3.It can be used microlevel as well as macrolevel. 

4.It is highly selective and convenient. 

5.It has the ability to separate the minor constituents from major constituents. 

6.It is speedy and rapid technique.