GB743491A - Improvements in and relating to the production of omega-amino nonanoic acid - Google Patents

Abstract

o -Amino nonanoic acid is prepared by subjecting an unsaturated acid occurring naturally in vegetable oils and having the formula R-CH=CH(CH2)7COOH, R being an aliphatic monovalent radical, to oxidative cleavage to form azelaic semi-aldehyde OHC-(CH2)7COOH, together with a further aldehyde RCHO as byproduct, the oxidative cleavage being effected either by reacting the acid with hydrogen peroxide to form a corresponding dihydroxy substituted acid and oxidizing this acid to form the aldehydes or by reacting the acid with ozone to form an ozonide which is subjected to hydrolysis or catalytic hydrogenation to form the aldehydes, and then either reacting the azelaic semi-aldehyde with hydroxylamine to form azelaic semi-aldoxime and hydrogenating the aldoxime in the presence of a hydrogenation catalyst to the desired amino-nonanoic acid or hydrogenating the azelaic semi-aldehyde in the presence of ammonia and a hydrogenation catalyst to the same amino acid. In a modification of the process, esters of the aminononanoic acid are prepared following the same sequence of reactions and either starting with an ester of the original unsaturated acid or esterifying one of the intermediate products which contains an esterifiable carboxylic group, for example, the azelaic semi-aldehyde or dihydroxy acid. In examples: (1) oleic acid in dry ethanol is treated with ozonized oxygen and the resulting solution of ozonide is hydrogenated in presence of palladium on calcium carbonate as catalyst; the aldehyde mixture formed is reacted with hydroxylamine hydrochloride in presence of excess sodium acetate and the solution refluxed; after removal of solvent, pelargonic aldoxime is precipitated by excess of aqueous sodium carbonate and thereafter azelaic semi-aldoxime is precipitated on acidification; the azelaic semi-aldoxime is hydrogenated in ethanolic solution in presence of ammonia and a Raney nickel catalyst and the ammonium salt of the desired amino-nonanoic acid recovered from the product and converted into the free amino-acid; the aldehydic products of the oxidative cleavage may be separated before the oxime-formation step by distillation or the semi-carbazone method; (2) oleic acid is hydroxylated with hydrogen peroxide and acetic acid, and the resulting 9 : 10-dihydroxy stearic acid recovered and converted to its ethyl ester; the ester is oxidized in dry benzene with lead tetra-acetate and the so-obtained pelargonic aldehyde and the ethyl ester of azelaic semi-aldehyde recovered by distillation; the ethyl ester is converted into its oxime which is hydrogenated as in (1) to yield ethyl 9-amino nonanoate; (3) as in (2), the ethyl ester of the azelaic semi-aldehyde being hydrogenated in ethanolic solution in presence of ammonia and Raney nickel to form ethyl amino nonanoate. Reference is also made to linoleic and ricinoleic acids and their esters. According to the Provisional Specification, R is any monovalent radical.