Question

When salicaldehyde is mixed with methylamine in a Schiff’s base condensation reaction why is an excess of methyl amine used in the reaction ?

Answer 1

When salicylaldehyde is mixed with methylamine in a Schiff's base condensation reaciton, an excess of methylamine is required to force the reaction, move in forward direction.

Explanation: As the water formed in the condensation reaction causes the hydrolysis of imine generated in the reaction and moves in backward direction towards the aldehyde. Thus an equilibrium will be established between the aldehyde (starting substrate) and imine (end product). If you add an excess of amine in the reaction, it will avoid the hydrolysis of amine and pushes the reaction towards the product (imine) side.