Patent GB-433780-A (GB)
Title: Improvements in the recovery of fatty acids or their salts
IPC: C07C51/487
Filed: 1934-02-14
Abstract: Carboxylic acids or salts thereof are obtained from oxidation products of liquid or solid nonaromatic hydrocarbons by heating the oxidation products to temperatures above 200 DEG  C. in the presence of hydrogen under pressure and in the presence of alkaline substances, during or after the saponification, and then removing the unsaponifiable products.  The acid may be obtained by acidifying with mineral acid.  During the heating any water present or formed may be removed.  Substances such as alumina, thoria, or titanium dioxide which promote splitting off of water, or substances which lighten the colour such as silica, kaolin, bleaching earth, or catalysts such as copper, or magnesium powder may be added to the saponification mixture.  Substances such as zinc dust or aluminium powder which cause evolution of hydrogen may be added to the saponification mixture.  The oxidation products may be treated while dissolved in organic solvents.  The unsaponifiable products may subsequently be removed by distillation or extraction with solvents.  The soap solution may be evaporated or the fatty acids may be precipitated by addition of mineral acid.  In examples, paraffin oil or wax oxidation products or soaps therefrom are heated under pressure with caustic soda in an atmosphere of hydrogen produced in some cases by the addition of zinc dust, with or without a nickel catalyst.  The unsaponifiable substances are removed by means of methyl alcohol, isopropyl alcohol, or benzine.  In another example, a paraffin wax oxidation product is saponified with caustic potash and then heated in hydrogen under pressure with basic copper carbonate. The pressure is released at intervals to allow water vapour to escape.  In other examples, the oxidation products are heated with calcium hydroxide, or caustic soda containing copper sulphate, or caustic soda containing a zinc-copper catalyst, or caustic soda containing aluminium dust, or magnesium powder.  The Provisional Specification describes also processes in which the heating with alkaline substances is carried out in the absence of hydrogen.ALSO:Soaps of carboxylic acids are obtained from oxidation products of non-aromatic hydrocarbons by heating the oxidation products to temperatures above 200 DEG  C. in the presence of alkaline substances during or after saponification, and in the presence of hydrogen under pressure, and then removing the unsaponifiable products. Water present or formed may be removed during the heating. Substances such as alumina, thoria, or titanium dioxide which promote splitting-off of water, or substances such as silica, kaolin, or bleaching earth which lighten the colour, or catalysts such as copper, or magnesium powder may be added to the saponification mixture.  Substances such as zinc dust, or aluminium powder which cause evolution of hydrogen may be added. The oxidation products may be treated while dissolved in organic solvents.  The unsaponifiable products may be removed by distillation or extraction with solvents.  In examples, paraffin oil or wax oxidation products or soaps therefrom are heated under pressure with caustic soda in an atmosphere of hydrogen produced in some cases by zinc dust, with or without a nickel catalyst. The unsaponifiable substances are removed by methyl alcohol, isopropyl alcohol, or benzine.  In another example, a paraffin wax oxidation product is saponified with caustic potash and then heated in hydrogen under pressure with basic copper carbonate. The pressure is released at intervals to allow water vapour to escape.  In other examples, the oxidation products are heated with calcium hydroxide, or caustic soda containing copper sulphate, or caustic soda containing zinc-copper catalyst, or caustic soda containing aluminium or magnesium powder. The Provisional Specification describes also processes in which the heating with alkaline substances is carried out in the absence of hydrogen.