Valerianic acid, it is well known, occurs preformed in certain plants; and it is equally well known, that it can be produced in the laboratory by artificial means. This very fact is of great interest to the investigating chemist, as it encourages him in the belief that he will, sooner or later, be able to produce artificially, not only acids, which are known to exist in the animal and vegetable kingdoms; but that he will so far imitate Nature in her wonderful processes, as to produce the vegetable alkaloids, morphia, quina, &c., by the combination of their elements.
The acid employed in the preparation of this series, _for which I have had the honor of being awarded a Prize Medal by the Jurors of the Great Exhibition_, was prepared, in principle, the same as that directed to be used by the Dublin Pharmacopœia in the preparation of valerianate of soda, namely, the oxidation of Fusel oil by means of chromic acid. The formula I employed is as follows:―
Take of Bichromate of potash, 2 parts. Oil of vitriol, 3 parts. Water, 4 parts. Pure Fusel oil, 1 parts.
The bichromate of potash is to be finely powdered and dissolved in the water; the solution being put into a glass retort, the oil of vitriol is gradually added, and, when quite cold, the _fusel oil_ is carefully added; the contents of the vessel must be constantly agitated, and at the same time kept immersed in cold water. The deep green liquid is now distilled from a sand bath; the distillate is mixed with caustic soda, or potash, and separated from the oily fluid floating on the surface; the _valerianate of soda_ is evaporated to a convenient degree of concentration, introduced into a retort, decomposed with dilute sulphuric acid, and distilled; the liberated valerianic acid is finally dried over chloride of calcium.
It is also obtained by the oxidation of oil of valerian, by means of an alkali. It is formed from fats, by treating them { 110} with fuming nitric acid; from animal nitrogenous matters, both by putrefaction and on decomposing them with strong nitric acid; and also if leucine be treated with caustic potash, or allowed to putrefy, it becomes converted into valerianic acid (no other acid being formed), ammonia and hydrogen being evolved.