What is the purpose of separating the reaction mixture with DI water?

Separating the reaction mixture with deionized (DI) water primarily serves to purify the product. When a reaction is conducted in an organic solvent, the desired product may be mixed with unreacted starting materials, byproducts, and the solvent itself. By adding DI water, different components of the mixture can be separated based on their solubility.

Generally, organic compounds are less soluble in water, while ionic or polar impurities tend to dissolve. As a result, after the separation, the organic layer containing the product can be collected, while the water layer (which may contain impurities) can be discarded. This process is an example of a simple liquid-liquid extraction, a common technique used in organic chemistry to isolate pure compounds from a complex mixture.

This purification step is crucial since it helps ensure that subsequent analyses, such as spectroscopy or chromatography, can be performed on a more refined product, ultimately leading to more accurate results.