Study on the reaction of amines with internal epoxides

Abstract

The reactivity of internal epoxides, as in epoxidized fatty acids, with primary amines was investigated using primary amines and a model epoxide compound, which was a mixture involving cis‐ and trans‐isomers of 9,10‐epoxyoctadecane.The reactions were carried out at 100, 170, and 200°C for 24 h. It was observed that the reaction of an amine with an internal epoxide does not proceed to any significant extent even at 200°C in the absence of catalysts.Practical applications: The model reaction of an amine with 9,10‐epoxyoctadecane is helpful to understand the reaction of amines with epoxidized vegetable oils. It revealed that the key step in the reaction of amine with epoxidized vegetable oils, in the absence of a catalyst, is amidation.Model compound, 9,10‐epoxyoctadecane (E‐OCD), was prepared and reacted with n‐octylamine and ehtanolamine without catalysts. GPC showed that in the absence of catalysts, ring opening of an internal epoxide with amine does not take place to any significant extent. While ring opening in the presence of OH groups happens to a higher extent. OH groups could act as reactants or catalysts.