Patent GB-396769-A (GB)
Title: Improvements in the separation of unsaponifiable matter from oils, fats, waxes, mixtures containing fatty acids, and crude soaps
IPC: C07C51/44
Filed: 1932-02-08
Abstract: Oxidation products of non-aromatic hydrocarbons or other mixtures containing fatty acids such as fats, oils, waxes, &c. are freed from unsaponifiable substances of high molecular weight by heating the crude alkali metal soaps prepared from the raw material, in a closed vessel under pressure, removing the water therefrom by releasing the pressure and distilling off the volatile substances from the anhydrous molten soap.  In examples, paraffin oil or wax is treated with nitric acid under pressure generated by the resulting nitrogen oxides.  The product is freed from nitric acid and is heated to 200-250 DEG  C. in an autoclave, with caustic potash or soda or sodium carbonate, under a pressure of 10 to 30 atmospheres whereby nitrogen compounds are removed and saponification is effected. Pressure is then released allowing the steam to escape and the residue is heated preferably at a higher temperature, e.g. 310 DEG C., and if desired in vacuo or in a p  current of steam or inert gas such as carbon dioxide, nitrogen or waste gases, whereby ketones, aldehydes, alcohols and hydrocarbons are distilled off and condensed. The process may also be applied to wool grease to separate the wool fat alcohols therefrom.  In a further example, soya bean oil is hydrogenated at 265 DEG  C. and under 200 atmospheres pressure in presence of a copper catalyst, and the fatty alcohols thus formed are removed from the hydrogenated oil by saponification under pressure, followed by distillation &c.  The anhydrous soaps residue may be decomposed by mineral acid to produce the fatty acids which are then submitted to further hydrogenation to form alcohols.  The soya bean alcohols thus made may be sulphonated to form wetting agents. Specifications 155,866, [Class 91, Oils &c.], and 364,574 are referred to.ALSO:Fats, oils, waxes, oxidation products of non-aromatic hydrocarbons and other mixtures containing fatty acids are freed from unsaponifiable substances of high molecular weight by heating the crude alkali metal soaps prepared from the raw material in a closed vessel under pressure, removing water therefrom by releasing the pressure, and then distilling off the volatile substances from the anhydrous molten soap.  Bleached montan wax, wool grease, spermaceti or hydrogenated soya bean oil is heated to 200-300 DEG  C. with aqueous caustic potash or soda, or sodium carbonate, in an autoclave under a pressure of 10-30 atmospheres.  Pressure is then released allowing steam to escape, and the residue is heated to 310 DEG  C. and if desired in vacuo, or in a current of steam or inert gas such as carbon dioxide, nitrogen or waste gases, whereby unsaponifiable products, e.g. alcohols, aldehydes, ketones and hydrocarbons are distilled off and condensed.  The soap residue may be dissolved in water and fatty acids recovered by addition of a mineral acid and the fatty acids thus formed are purified by distillation in vacuo or in steam and used in manufacture of soap. In the treatment of hydrogenated soya bean oil, the separated fatty acids may be submitted to further hydrogenation and converted into alcohols. The resulting alcohols may be sulphonated to form wetting agents. Oxidation products of paraffin oil or wax with nitric acid, or oxides of nitrogen may also be treated, when the initial treatment with alkali to form soaps also removes nitrogen compounds. Saponification may be effected by mixing the oil &c. and alkali in a heated tube and pumping the resulting emulsion through a second tube heated under pressure.  The saponification product then passes through a third heated tube from which it passes through a release valve into a separator condenser containing Raschig rings over which cold water flows.  The distillation step may be effected in rotating vessels whereby the molten soap flows around the walls of the vessel. Specifications 155,866, [Class 91, Oils &c.], and 364,574 are referred to.