1565. ------. [I. G. FARBENINDUSTRIE, A. G.] Soap. British Patent 487,317. June 13, 1938. Chem. Abs., vol. 32, 1938, p. 9539.

Saponified oxidation products of nonaromatic hydrocarbons of high molecular weight are freed from unsaponifiable constituents by introducing such saponaceous mixture containing at least 25% of H₂O into a tubular vaporizing plant at 100 atm. or higher pressure and releasing the pressure to atmospheric within the tube system, the temperature in the tubes being such, for example, 310º-350º, as to maintain the soap liquid. The pressure may be reduced in stages, and a vacuum pump may be arranged beyond the condenser for the steam and unsaponifiables to insure that the pressure falls to atmospheric in the tube system. Before saponification, the oxidation products may be freed from readily soluble and strongly acid products by H₂O, acids, dilute alkali, or organic solvents. The saponification may be effected in presence of H₂O, alcohols, ketones, or hydrocarbon solvents and by the saponification equivalent or more or less of alkali. Before treatment in the vaporizer, the saponified mixture is preferably (1) freed from any unsaponifiables separating as an upper layer, (2) maintained >200º for some time to convert lactones, hydroxy acids, into ordinary fatty acids and improve the color and odor; the preheat treatment may be in presence of hydrogenating agents, for example, H₂ or Zn dust. Describes apparatus.