The process of manufacturing soaps by boiling fatty acids with caustic alkalis or sodium carbonate came into practice with the development of the manufacture of candles by saponifying fats, for it provided a means whereby the oleic acid, which is valueless for candle making, could be worked up. The combination is effected in open vats heated by a steam coil and provided with a stirring appliance; if soda ash be used it is necessary to guard against boiling over.
Oleic Acid >>
These enabled him to elucidate the true nature of soap; he was also able to discover the composition of stearin and olein, and to isolate stearic and oleic acids, the names of which were invented by him.
Very good results have been obtained from a preparation named "lipanin," which consists of six parts of oleic acid and ninety-four of pure olein.
By saponification it yields a number of fatty acids - palmitic, myristic, oleic, linolic, linolenic and isolinolenic. Exposed to the air in thin films, linseed oil absorbs oxygen and forms " linoxyn," a resinous semi-elastic, caoutchouclike mass, of uncertain composition.
It is most conveniently obtained from olive oil, after removal of the oleic acid, or from Japanese beeswax, which is its glyceride.
Artificially it may be prepared by heating cetyl alcohol with soda lime to 270° or by fusing oleic acid with potassium hydrate.
OLEIC ACID, C13H3402 or C 8 111 7.
Oleic acid is a colourless, odourless solid, melting at 14° and boiling at 223° (Io mm.).
Hydriodic acid reduces both oleic and elaidic acids to stearic acid.
Erucic acid, C 8 H 17 CH: CH [CH2]11 C02H, and the isomeric brassidic acid, belong to the oleic acid series.
The unsaturated fatty acids which occur chiefly in oils and fats are oleic acid, iodine value 90.07; erucic acid, iodine value 75.15; linolic acid, iodine value 181.42; linolenic acid, iodine value 274.1; and clupanodonic acid, iodine value 367.7.
It is also obtained when sebacic, stearic and oleic acids are oxidized with nitric acid.
Oleic acid occurs in all non-drying oils and fats, and to some extent in the semi-drying oils and fats.
In the mixture of unsaturated fatty acids, by means of some more refined methods, clupanodonic acid, linolenic acid, linolic acid and oleic acid can be recognized.