GB697293A - Improvements in or relating to the production of nitriles - Google Patents

Abstract

Nitriles are obtained by a process which comprises the step of reacting at an elevated temperature and in liquid phase a high molecular weight fatty acid material and ammonia in the presence of phosphorus as catalyst. The fatty acid material is defined as a fatty acid containing six or more carbon atoms in the hydrocarbon group or an ester or anhydride of such acid. The fatty acid may be saturated, mono-unsaturated or polyenic and specified acids are lauric, palmitic, stearic, oleic, ricinoleic, linoleic, linolenic, and elaeostearic acids. Mixed acid stocks such as tall oil and the acid obtained by hydrolysis of linseed oil, cotton-seed oil, soyabean oil and castor oil may also be used and the natural acid mixtures obtained, for example, from linseed oil or soyabean oil may be fractionated, e.g. by fractional distillation or fractional crystallization to obtain an acid fraction containing a higher proportion of polyene acids which is then subjected to the reaction with ammonia. When polyene acids are employed the nitrile product is substantially polymeric. The phosphorus may be used in its various forms but it is preferred to use red or amorphous phosphorus. The process may be carried out batchwise or in a continuous manner and suitable apparatus for carrying out the process in a continuous manner is described and p illustrated. In examples: (1) a mixture of dehydrated castor oil fatty acids and red phosphorus is heated and a stream of ammonia gas bubbled through the liquid at 310-315 DEG C. The monomeric nitriles are removed from the reaction mixture by vacuum distillation leaving the polynitriles in the residue; (2) a mixture of castor oil fatty acids and red phosphorus is heated at 310-315 DEG C. in a stream of ammonia and the product treated as in (1) to yield monomeric and polymeric nitriles; (3) as in (2) using dehydrated castor oil acids; (4) linseed oil fatty acids and red phosphorus are processed as in (1); (5) distilled soyabean oil fatty acids and red phosphorus are processed as in (1); (6) a mixture of dehydrated castor oil fatty acids and red phosphorus is heated with ammonia gas at temperatures increasing from 320 DEG to 350 DEG C. and the product treated as in (1). The polynitriles are stated to be useful as plasticizers for synthetic resins and may be reacted with hydrogen in the presence of hydrogenating catalysts such as nickel and platinum to produce polyamines which are also useful as plasticizers. The hydrogenation may be effected at 120-170 DEG C. and smaller pressures of 50 to 500 lbs. per square inch. The polyamines may be condensed with polycarboxylic acids to form polyamides which are useful as coating compositions.