Question

LAB: Nucleophilic reactions of aldehydes and ketones.

1. What properties are desirable in a derivative? why does a liquid make a poorer derivative than a solid?

Answer 1

A derivative of the sample in the laboratory is normally required to have physical state - solid.

It is easy to filter a solid derivative from the reaction mixture and it can be easily purified by recrystallisation in a suitable solvent.

The characterisation of solid derivative also is easy by taking melting point and mixed melting point.

With aliquid derivtive , the separation is through solvent extraction , which is cumbersome and the characteirsation also difficutl as we need to check boiling point, which is again time /labor consuming.

Thus we prefer to prepare solid derivatives of aldehydes and ketones like 2,4 -DNP , oxime or semicarbazones.