A simple method is presented that enables students to distinguish in a few minutes between primary, secondary and tertiary alkyl alcohols. This method is based on peculiarities of absorption spectra in the near-UV region of alkyl nitrites, the products of alcohol nitrosation.
All tertiary nitrites have a maximum at ca.
400 nm whereas all primary and secondary nitrites do not have such a maximum. The discrimination between two latter nitrites is based on the ratio of the heights of two adjacent maxima at ca. The assignments are proposed for students, including nitrosation procedure, taking spectra, plotting graphs, deducing linear dependence and investigating of further possibilities of alcohol mixture analysis. An Experiment in Spectrophotometry, Organic Chemistry, and Analytical Chemistry J. Chem. April 1997 Vol.