What is the name of the process of separation of a racemic mixture into the respective 'd' and 'l' optical isomers?

Resolution

The correct answer is option 1. Resolution.

The process of separating a racemic mixture into its respective 'd' (dextrorotatory) and 'l' (levorotatory) optical isomers is called resolution.

A racemic mixture contains equal amounts of both enantiomers, which are molecules that are non-superimposable mirror images of each other. These enantiomers have identical physical properties except for the direction in which they rotate plane-polarized light. Because of this, a racemic mixture does not exhibit optical activity since the effects of the two enantiomers cancel each other out.

Resolution is the process used to separate these enantiomers to obtain the pure optical isomers. This can be achieved through various methods, such as:

1. Crystallization: A common method involves the formation of diastereomeric salts by reacting the racemic mixture with a chiral resolving agent. These diastereomeric salts have different solubilities and can be separated by crystallization. Once separated, the pure enantiomers can be recovered by breaking down the salts.

2. Chromatography: Chiral chromatography uses a chiral stationary phase that interacts differently with each enantiomer, allowing them to be separated as they pass through the column.

3. Enzymatic Resolution: Specific enzymes that preferentially react with one enantiomer over the other can be used to selectively convert one enantiomer into a different compound, leaving the other enantiomer unchanged.

By using these methods, chemists can obtain pure 'd' and 'l' forms from a racemic mixture, which is crucial in many fields, especially in pharmaceuticals, where the biological activity of enantiomers can differ significantly.