Separation of organic compounds

Introduction

The Separation of a mixture of organic compounds to give the pure components is of the great practical importance in chemistry. Many synthetic reactions react to give mixture of products. It is necessary to have a reasonably clear idea of how the mixture of compounds can be separated out. Almost all the compounds which have the interest of biochemical occurs naturally as components of very complex mixture from which they can be separated out only with considerable difficulty and efficiency.

Separations of organic compounds can be achieved by differences in physical and chemical properties, such as differences in boiling point, melting point etc. or by chemical means, having differences in physical properties which are regulated by chemical reactions.

Problems in Separation of organic compounds

A common problem arises in organic chemistry involves the separation of a mixture of two or three organic compounds into single compound fractions followed by the purification and identification of each organic compound.  To effect the separation of organic compounds, the chemist must make use of the different properties of the components. The phenomena such as differences in solubility, density, acid-base chemistry and reactivity are used to separate a mixture of organic compounds.

Then each component is purified and identified.  For example the carboxylic acid can react with a base such as sodium hydroxide and forms an anion which is water soluble. The neutral doesn’t react and so it remains “neutral”. The possible organic neutral compounds are separated out.

Utility of Separation of organic compounds

It is important to note that single extractions of organic compound for its separation do not necessarily yield complete separations, and that multiple extractions sometimes needed. It includes the extraction the original organic solution two times with aqueous sodium hydroxide solution to remove the acid and water soluble impurities from the organic layers of mixture.

The two aqueous extracts are then combined with each other and set aside as the aqueous sodium hydroxide fraction. The organic compound is further extracted once with distilled water to remove any water soluble impurities.  Once these extractions of organic compound are complete, the organic solution should contain only the "neutral" compound.