DATE:23 RD JANUARY,2014.
TITLE: SEPARATION AND PURIFICATION OF ORGANIC COMPOUNDS
To isolate organic, inorganic and component from a given sample. To become acquainted with various separation methods.
To examine the solubility behavior of the various compounds in a mixture using different solvents.
INTRODUCTION A commonly used method of separating a mixture of organic compounds is known as liquid-liquid extraction. Most reactions of organic compounds require extraction at some stage of product purification. In this experiment you will use extraction techniques to separate a mixture of an organic acid, a base, and a neutral compound. Organic acids and bases can be separated from each other and from neutral compounds by extraction using aqueous solutions of different pH values. Most organic carboxylic acids are insoluble or slightly soluble in water, but these compounds are highly soluble in dilute aqueous sodium hydroxide because the acid is deprotonated by the base producing the sodium carboxylate salt.
The carboxylic acid can be selectively isolated by dissolving the mixture in an organic solvent that is immiscible with water, and then extracting the solution with sodium hydroxide. The basic aqueous solution containing the carboxylate salt is acidified, causing the sodium carboxylate salt to convert back to the carboxylic acid, which is not water soluble. The acid will precipitate from the solution, as shown here.
Organic bases (e.g., amines) that are insoluble in water can be separated by extraction...
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