‎"HOFMANN, A.W. (AUGUST WILHELM von). - THE TRUE NATURE OF AMINES DEMONSTRATED.‎
‎Reseraches into the Molecular Constitution of the Organic Bases. (Second Memoir). Communicated by James Clark. Received March 12, - Read April 3, 1851.‎

‎(London, Richard Taylor, 1851). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1851 - Part I. Pp. 357-398.‎

Reference : 44307

‎First appearance of a landmark paper in organic chemistry in which Hofmann demonstrates the true nature of amines.""Wurtz had shown the existence of methyl and ethyl amines and had suggested that that they may be regarded as derivatives of ammonia. Hofmannproved this in adetailled study, in which he showed that all hydrogens of ammonia, and even of the ammonia radical, could be replaced by organic groups to give primary, secondary, and tertiary amines, and quaternary ammonium compounds. In the course of this work, he also cleared up the relation between ammonia and the ammonium radical which had long troubles chemists. The investigation was carried out in 1850, at a time when the type theory was foremost in theminds of organic chemists. It was therefore natural that Hofmann should formulate his nes compounds as representative of the ""ammonia type"". The formulas which he wrote, however scarcely differ from those used today. These clear examples helped Frankland in developing his theory of variable valence.""(Klickstein p. 364). Klickstein's selection is taken form the offered item pp. 392-397.‎