On the constitution and properties of picoline : a new organic base from coal-tar / [Thomas Anderson].

  • Anderson, Thomas, 1819-1874
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: On the constitution and properties of picoline : a new organic base from coal-tar / [Thomas Anderson]. Source: Wellcome Collection.

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    heavier than water, a layer of which, containing a small pro¬ portion of oil in solution, floated on the surface. The exa¬ mination of this oil proved it to consist, in addition to pico¬ line, of a mixture of pyrrol, aniline, an oily base possessing the general properties of leukol, and a thick heavy oil desti¬ tute of basic properties. In order to separate picoline, the oil, along with the water which floated on its surface, was introduced into a retort and carefully distilled. At first, water, accompanied by a little oil, passed over, and then an oil by itself, which dissolved completely in the watery fluid contained in the receiver.* As the distillation proceeded, another oil made its appearance, which collected in a layer on the surface of the fluid which had previously distilled. When about three-fourths of the oil had passed over, the process was stopped, by which means the oil, destitute of basic properties, wdiich requires a very high temperature for its distillation, was left behind in the retort. The fluid in the receiver was now supersaturated with sulphuric acid diluted with water, care being taken to obtain a powerfully acid reaction. The peculiar odour which the fluid possessed, was by this process entirely changed, but not destroyed; and, on distillation, the water which passed over, carried with it all the pyrrol contained in the solution, while the other bases were retained by the sulphuric acid. Caustic potass was then added to the residue in the retort until an alkaline reaction was manifest, and it was again distilled; the water which passed over carried with it the oily bases, partly dissolved, partly floating on the surface of the solution, exactly as in the first distillation. A few sticks of fused potass were introduced into the product, and the wdiole was left in repose; as the potass dissolved, the oil, which is entirely insoluble in solutions of the fixed alkalis, rose to the surface and there collected in the form of a pale yellow layer, still containing a considerable quantity of water, which may amount to 30 or 40 per cent, of the bulk of the oil. The oil was separated from the watery fluid by means of a pipette and pieces of fused potass added so long as they continued to become moist. The dry oil was then introduced into a retort and distilled. A. transparent and colourless oil