Patent GB-704579-A (GB)
Title: Method of removing ketones from fatty acids
IPC: C07C51/487
Filed: 1951-12-10
Abstract: Fatty acids having from 6 to 22 carbon atoms and mixed with ketones are purified by adding to the mixture a base capable of forming a water soluble soap with the fatty acids, forming an aqueous solution of the soap of concentration 20-30 per cent. and separating the soap solution from the mixture.  The method is particularly applicable to the purification of a mixture of fatty acids which are obtained as a by-product of an esterification reaction conducted at elevated temperatures.  Such mixtures may be obtained from the reconstruction of glyceride oils of the coconut type wherein lower fatty acids are displaced by higher fatty acids and are removed by volatilization. The bases used to form a soluble soap may be added as an aqueous solution or as such, water being subsequently added to dissolve the soap formed.  The base used may be organic and may be an aromatic or aliphatic amino compound or a cyclic nitrogen compound. Alternatively it may be inorganic, e.g. caustic soda, potassium or ammonium hydroxide or a carbonate or bicarbonate of an alkali metal. In the examples (a) a mixture of fatty acids containing largely acids of 6, 8 and 10 carbon atoms and ketones as impurities are treated with caustic soda solution in sufficient quantity to give a soap solution of 20-30 per cent. strength; the upper layer containing ketones and other impurities is removed and the lower layer is treated with an acid such as sulphuric acid to release the free fatty acids: (b) to a similar mixture of fatty acids as in (a) is added triethanolamine and the soap formed is brought to a concentration of 20-30 per cent. by the addition of water; the soap layer is removed and the free fatty acids are released from it by the addition of acid.ALSO:Fatty acids having from 6 to 22 carbon atoms and mixed with ketones are purified by adding to the mixture a base capable of forming a water soluble soap with the fatty acids, forming an aqueous solution of the soap of concentration 20-30 per cent. and separating the soap solution from the mixture.  The method is particularly applicable to the purification of a mixture of fatty acids which are obtained as a by-product of an esterification reaction conducted at elevated temperatures.  Such mixtures may be obtained from the reconstruction of glyceride oils of the coconut type wherein lower fatty acids are displaced by higher fatty acids and are removed by volatilization.  The bases used to form a soluble soap may be added as an aqueous solution or as such, water being subsequently added to dissolve the soap formed.  The base used may be organic and may be an aromatic or aliphatic amino compound or a cyclic nitrogen compound. Alternatively, it may be inorganic, e.g. caustic soda, potassium or ammonium hydroxide or a carbonate or bicarbonate of an alkali metal. In the examples (a) a mixture of fatty acids containing largely acids of 6, 8 and 10 carbon atoms and ketones as impurities is treated with caustic soda solution in sufficient quantity to give a soap solution of 20-30 per cent. concentration; the upper layer containing ketones and other impurities is removed and the lower layer is treated with an acid such as sulphuric acid to release the free fatty acids (b) to a similar mixture of acids as in (a) is added triethanolamine and the soap formed is brought to a concentration of 20-30 per cent. by the addition of water; the soap layer is removed and the free fatty acids are released from it by the addition of acid.