Preparation of 9-hydroxynonanoic acid methyl ester by ozonolysis of vegetable oils and its polycondensation

Abstract

Vegetable oil-based and potentially biodegradable polyesters were prepared from 9-hydroxynonanoic acid methyl ester. This paper describes ozonolysis of vegetable oils and the method for preparation of useful monomers and in particular 9-hydroxy- nonanoic acid methyl ester. Ozonolysis of soybean oil and castor oil in methanol and methylene chloride solution, followed by reduction with sodium borohydride was used to obtain a mixture of triols, diols and monols. Triglyceride triols were separated from the rest of the mixture and transesterified with methanol to obtain methyl esters of fatty acids and glycerin. The main component of fatty acids was 9-hydroxynonanoic acid methyl ester, which was characterized and used for polycondensation by transesteri-fication. High molecular weight polyhydroxy alcanoate was a solid having a melting point of 75 °C. The molecular weight of the resulting polyester was affected by the purity of the monomer and side reactions such as cyclization. The polymer was characterized by chromatographic, thermal and analytical methods.