Patent GB-630634-A (GB)
Title: Improvements in or relating to the conjugation of fatty oils and acids
IPC: B29C45/14
Filed: 1947-06-06
Abstract: Drying and semi-drying oils or fatty acids from such oils are conjugated by heating the oil or acid in the presence of a small proportion of a catalyst consisting of iodine or hydrogen iodide and maintaining the oil or acid at the desired reaction temperature for a period of time sufficiently long to effect a substantial degree of conjugation and arresting the reaction before any significant degree of polymerization is produced.  The maximum degree of conjugation is indicated when the refractive index has reached a maximum, whereupon the reaction should be stopped.  This may be effected by immediate cooling of the reaction product or by removing the catalyst by chemical means such as by the addition of a small proportion of zinc dust which reacts to form zinc iodide, thus inactivating the catalyst.  In either case, the iodine is preferably removed from the conjugated oil or acid by first, if necessary, adding zinc dust to form the iodide and then washing out the latter with water.  A small quantity of chlorine or bromine may be added to the oil or acid before the addition of the catalyst, in which case a much less quantity of the latter is required.  The oils and acids specified comprise linseed oil, soya bean oil, sesame oil, maize oil and linseed oil fatty acids.  The process may be carried out by a batch method using a preferred temperature range of 180-200 DEG  C., when a few minutes is sufficient.  Alternatively, a continuous process may be used by passing the oil or acid and the catalyst through a heated tube and then continuously cooling the product by passing it through a similar tube surrounded by coolant, a temperature of 250 DEG  C. for a few seconds being preferably used. In this case, the quantity of catalyst may be reduced.  The proportion of catalyst preferably lies within the range of 0.5-2.0 per cent by weight based on the weight of the oil or acid.  Specification 338,932, [Class 91], and U.S.A. Specification 1,896,467 are referred to.ALSO:Fatty acids from drying and semi-drying oils are conjugated by heating the acid in the presence of a small proportion of a catalyst consisting of iodine or hydrogen iodide, maintaining the acid at the desired reaction temperature for a period of time sufficient to effect a substantial degree of conjugation, and arresting the reaction before any significant degree of polymerisation is produced.  The maximum degree of conjugation is indicated when the refractive index has reached a maximum, whereupon the reaction should be stopped.  This may be effected by immediate cooling of the reaction product or by removing the catalyst by chemical means such as by the addition of a small proportion of zinc dust which reacts to form zinc iodide, thus inactivating the catalyst.  In either case, the iodine is preferably removed from the conjugated acid by first, if necessary, adding zinc dust to form the iodide and then washing out the latter with water. A small quantity of chlorine or bromine may be added to the acid before the addition of the catalyst, in which case a much less quantity of the latter is required.  Linseed oil fatty acids are specified.  The process may be carried out by a batch method using a preferred temperature range of 180-200 DEG  C., when a few minutes is sufficient. Alternatively, a continuous process may be used by passing the acid and the catalyst through a heated tube and then continuously cooling the product by passing it through a similar tube surrounded by coolant, a temperature of 250 DEG  C. for a few seconds being preferably used.  In this case, the quantity of catalyst may be reduced.  The proportion of catalyst preferably lies within the range of 0.5-2.0 per cent by weight based on the weight of the acid. Specification 338,932, [Class 2 (iii)], and U.S.A. Specification 1,896,467 are referred to.