Spectroscopic characterization and thermal behavior of baru nut and macaw palm vegetable oils and their epoxidized derivatives

Abstract

The ability to produce new and renewable, epoxidized Brazilian vegetable oils from baru nut (Dipteryx alata Vogel) and macaw palm (Acrocomia aculeata) oil, using a fast and clean heterogeneous catalytic method, was investigated. The Wijs method and Proton Nuclear Magnetic Resonance (1H-NMR) analysis were utilized, and compared to one another, to calculate the iodine value (IV), average number of double bonds (DBaverage) and fatty acid content, and thus degree of epoxidation, for both vegetable oils. This analysis indicated that alkene conversions of >99% and 95.3% were obtained for baru nut oil and macaw palm oil, respectively; which is an excellent result when compared with some works in literature. The epoxidized Baru nut oil is a solid at room temperature, which was related to the percentage of mono-unsaturated fatty acids present in its structure. Epoxide samples were also analyzed via mid-Infrared Spectroscopy and 13C NMR analysis. Thermogravimetry-differential thermal analysis (TG-DTA) was used to determine the thermal stability of these epoxidized oils. Differential Scanning Calorimetry (DSC) also provided information about their crystallization, melting and solid-solid transition processes.