Extractions, Separations, and Drying Agents

Solvent 1 contains a mixture of molecules (black and white). 

After shaking with solvent 2 (shaded), most of the white molecules have been extracted into the new solvent. The white molecules are more soluble In the second solvent, whereas the black molecules are more soluble in the original solvent. 

With removal of the lower phase with a Pasteur pipette, the black and white molecules have been partially separated. 

The washing operation helps purify the desired organic compound present in the original reaction mixture. 

When a solution (solute A in solvent 1) is shaken with a second solvent (solvent 2) with which it is not miscible, the solute distributes itself between the two liquid phases. When the two phases have separated again into two distinct solvent layers, an equilibrium will have been achieved such that the ratio of the concentrations of the solute in each layer defines a constant. The constant, called the distribution coefficient (or partition coefficient) K, is defined by 

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Crystallization Purification of Solids Extractions, Separations, and Drying Agents... 

Experiment 22 Nucleophilic Substitution Reactions Competing Nucleophiles Technique 7 Reaction Methods, Section 7.2,7.4,7.5, and 7.7 Technique 12 Extractions, Separations, and Drying Agents, Sections 12.5,... 

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