GB841554A - Improvements in or relating to the manufacture of polymeric fatty acids - Google Patents

Abstract

Polymeric acids are prepared by heating polyunsaturated fatty acids corresponding to natural fat acids, at least one of which contains conjugated double bonds, in the absence of added water in a closed vessel at a polymerization temperature and under the pressure autogenously so generated. In a modification, there is used as starting material a C18 hydroxy fatty acid or derivative thereof, which forms octadecadienoic acids consisting partly of the conjugated isomer at the said polymerizing temperature. The polymerization may be effected at 300 DEG to 350 DEG C. Polymerization catalysts such as finely-divided metals and anthraquinone may be present. In examples: (1) distilled dehydrated castor oil fatty acids; (2) polyricinoleic acid obtained by Twitchell-splitting of castor oil; and (3) castor oil fatty acids are heated in an autoclave at 330-350 DEG C. for 1-2 hours. In a comparative experiment, distilled dehydrated castor oil acids are heated in an open vessel in a nitrogen atmosphere at 330 DEG C., yielding a product having a lower acid value than that of (1).ALSO:Polymeric fatty acids are prepared by heating polyunsaturated fatty acids corresponding to natural fat acids, at least one of which contains conjugated double bonds, in the absence of added water in a closed vessel at a polymerization temperature and under the autogenous pressure so generated. In a modification, there is used as starting material a C18 hydroxy fatty acid or derivative thereof, which forms octadecadienoic acids consisting partly of the conjugated isomer at the said polymerization temperature, such as castor oil fatty acids, mixtures of castor oil fatty acids and polyricinoleic acids obtainable by splitting castor oil in an autoclave, polyricinoleic acid and derivatives of such products where the OH groups are esterified with octadecadienoic acids. Polymerization temperatures of 300 DEG to 350 DEG C. may be used and catalysts such as finely-divided metals and anthraquinone may be present. In examples: (1) distilled dehydrated castor oil fatty acids, (2) polyricinoleic acid obtained by Twitchell-splitting of castor oil, and (3) castor oil fatty acids are heated in an autoclave at 330-350 DEG C. for 1-2 hours. A comparative experiment describes heating distilled dehydrated castor oil acids in an open vessel in a nitrogen atmosphere at 330 DEG C. yielding a product having a lower acid value than that of (1).