Old compounds of hydrogen and nitrogen

Vinegar and Pyroligneous Acid. Vinegar (acetic acid) is mentioned several times in the Bible, as, for example, in Proverbs 10, 26 As vinegar to tire teeth and as smoke to the eyes, so is the sluggard to them that send him. It was known to Theophrastus three centuries before the birth of Christ, and was used in tire manufacture of white lead and verdigris and in extracting mercury from cinnabar (I). 

Because of its relation to saltpeter, P.-J. Macquer regarded nitric acid as a kind of sulfuric acid modified by its passage through animal and vegetable substances. In 1750, said he, the Royal Academy of Sciences at Berlin proposed an account of the generation of Nitre as the subject for their prize, which was conferred on a Memoir wherein this last opinion was supported by some new and very judicious experiments (8). Macquer stated that the Nitrous [nitric] Acid is never found but in earths and stones which have been impregnated with matters subject to putrefaction. (8). 

The first industrial preparation of sulfuric add from green vitriol (ferrous sulfate), according to Hermann Kopp, was by Johann Christian Bernhardt in 1755 (9,10). A fuming sulfuric acid known as Nordhausen oil of vitriol was manufactured at Nordhausen, Thuringia, from partially dehydrated green vitriol (11). 

Hermann Kopp found the earliest mention of the British process in Robert Dossie s Elaborately laid open m 1758. Dossie spoke only of glass receptacles for the acid (9). In his Institutes of Experimental Chemistry in the following year, he stated that this process had greatly lowered the price of oil of vitriol and had made possible the use of this acid in the preparation of aqua foitis (nitric acid) from saltpeter (7). 

In 1746 Dr. John Roebuck (1718-1794), of Birmingham, and Samuel Garbett substituted lead chambers, each about six feet square, for the glass globes introduced six years previously by Joshua Ward (22), an improvement which cut down the cost of producing the acid to one-fourth of its former amount (12, 13). Three years later, after the substitution of sulfuric acid for sour milk in the old process of bleaching had created a demand for the acid, Roebuck and Garbett erected a sulfuric acid plant at Prestonpans, on the east coast of Scotland (14). Since a salt industry also flourished there, Prestonpans was named for the salt pans. 

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The oxidation of amines by mercuric acetate is an old reaction (54) which up until recent years was employed primarily to modify alkaloid structures (55). A systemic study of the oxidizing action of mercuric acetate by Leonard and co-workers led to the development of a general method for the synthesis of enamines from cyclic tertiary amines. An observation made after a large number of compounds were oxidized, but which is worth noting at the onset, is that a tertiary hydrogen alpha to the nitrogen atom is removed preferentially to a secondary a-hydrogen. 

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