Hydrolysis of acetonitrile in the presence of NbCl5

Article abstract of DOI:10.1016/0277-5387(95)00432-7

The mechanism of the hydrolysis of acetonitrile to ammonium ion in the presence of NbCl⁵ has been investigated. Two possible mechanisms are discussed: metal-assisted (catalysed) hydrolysis and a mechanism based on the addition of alcohol and HCl to the CN triple bond to give initially an imidate hydrochloride salt, which may undergo further hydrolysis to the ester and ammonium ion (Pinner synthesis). Support for this route came from the spectroscopic identification of the alkoxyimminium ion intermediate, CH₃C(OCH₃) = NH⁺₂. Although the reaction is not catalysed by Nb, the extent of reaction is strongly related to the amount of Nb present. It is concluded that the Pinner reaction is operating with the amount of HCl available for the reaction being controlled by the Nb concentration.