Question

what is the role of adding the 2M MaOH to the amine tartrate salt prior to the extraction step with dichloromethane ?

Answer 1

Amine tartrate salt will be added to HCl, so that free amine and tartaric acid will be formed. The mixture is further treated with sodium hydroxide to remove tartaric acid as sodium tartrate salt and to remove excess HCl as sodium chloride these sodium chloride and sodium tartrate is highly soluble in water where as amine has good soluble in dichloromethane. Therefore by adding dichloromethane amine will be in organic layer where as sodium tartrate and sodium chloride will be in aqueous layer.