Amines are organic compounds formed from ammonia (NH₃ by the replacement of one or more hydrogen atoms by hydrocarbon groups (unlike the amides where the hydrogen in ammonia is replaced by organic acid groups). Primary amines have one hydrogen atom replaced by a hydrocarbon group, secondary amines have two hydrogen atoms replaced, and tertiary amines have all three hydrogen atoms replaced. In 1850 German chemist August von Hofmann (1818-1892) discovered that heating alkyl halides with an alcoholic solution of ammonia produces a mixture of the three types of amine. This process was modified in 1890 by Hinsberg to produce separate products, based on the different reactivity and solubilities of the three forms. This was a much easier method of obtaining the required chemicals than collecting them from herring brine, where they occur naturally.

Primary amines also are manufactured by a reaction known as the Hofmann degradation which takes...