reducing nitriles to primary amines

REDUCING NITRILES TO PRIMARY AMINES This page looks at the reduction of nitriles to primary amines using either lithium tetrahydridoaluminate(III) (lithium aluminium hydride) or hydrogen and a metal catalyst. The reduction of nitriles using LiAlH4 The reducing agent Despite its name, the structure of the reducing agent is very simple. There are four hydrogens ("tetrahydido") around the aluminium in a negative ion (shown by the "ate" ending). The "(III)" shows the oxidation state of the aluminium, and is often left out because aluminium only ever shows the +3 oxidation state in its compounds. To make the name shorter, that's what I shall do for the rest of this page.
The structure of LiAlH4 is: In the negative ion, one of the bonds is a co-ordinate covalent (dative covalent) bond using the lone pair on a hydride ion (H-) to form a bond with an empty orbital on the aluminium.
The overall reaction The nitrile reacts with the lithium tetrahydridoaluminate in solution in ethoxyethane (diethyl ether, or just "ether") followed by treatment of the product of that reaction with a dilute acid. Overall, the carbon-nitrogen triple bond is reduced to give a primary amine. Primary amines contain the -NH2 group. For example, with ethanenitrile you get ethylamine:     Notice that this is a simplified equation - perfectly acceptable to UK A level examiners. [H] means "hydrogen from a reducing agent".