The free fatty acid radicle then unites with an alkali, and becomes transformed into a soluble soap which is then readily absorbed in this fluid condition by the epithelial cells of the mucous membrane.
Some other glycerides isolated from natural sources are analogous in composition to tristearin, but with this difference, that the three radicals which replace hydrogen in glycerin are not all identical; thus kephalin, myelin and lecithin are glycerides in which two hydrogens are replaced by fatty acid radicals, and the third by a complex phosphoric acid derivative.
There is present in the seeds an enzyme which rapidly decomposes the oil if the seeds are crushed and kept, setting free a fatty acid and glycerin.
He acted as president of the International Congress held at Geneva in 1892 for revising the nomenclature of the fatty acid series.
A fat consisting of the glyceride of one fatty acid only, such as stearin or tristearin, C3H5(O C1811350)3, the glycerin ester of stearic acid, C17H35 C02H.
This is true of the fatty acid series, and the corresponding ketones and alcohols, and also of the succinic acid series.
It splits it into a fatty acid and glycerine, but seems to have no further action.
The processes of soap manufacture may be classified (a) according to the temperatures employed into (I) cold processes and (2) boiling processes, or (b) according to the nature of the starting material - acid or oil and fat - and the relative amount of alkali, into (1) direct saturation of the fatty acid with alkali, (2) treating the fat with a definite amount of alkali with no removal of unused lye, (3) treating the fat with an indefinite amount of alkali, also with no separation of unused lye, (4) treating the fat with an indefinite amount of alkali with separation of waste lye.
The conversion of the glycerides (triglycerides) into fatty acids and glycerin must be looked upon as a reaction which takes place in stages, one molecule of a triglyceride being converted first into diglyceride and one molecule of fatty acid, the diglyceride then being changed into monoglyceride, and a second molecule of fatty acid, and finally the monoglyceride being converted into one molecule of fatty acid and glycerin.
These discoveries of Geoffroy and Scheele formed the basis of Chevreul's researches by which he established the constitution of oils and the true nature of soap. In the article Oils it is pointed out that all fatty oils and fats are mixtures of glycerides, that is, of bodies related to the alcohol glycerin C 3H5(OH)3 i and some fatty acid such as palmitic acid (C 16 H 31 0 2)H.