Thermal and oxidative stabilities of binary blends of esters from soybean oil and non-edible oils (Aleurites moluccanus, Terminalia catappa, and Scheelea phalerata)

Edible oils remain the principal feedstocks for biofuel production. Given the potential impact of this use on the food supply chain, extensive research has supported the adoption of inedible oils for biodiesel generation, an approach that may help diversify the supply of oleochemical materials. This article reports an investigation of Scheelea phalerata, Terminalia catappa, and Aleurites moluccanus, three inedible oilseeds found in Midwest Brazil. Oils from these species were employed to synthesize biodiesel (methyl route) and produce binary blends with soybean biodiesel (S. phalerata : soybean, T. catappa : soybean, and A. moluccanus : soybean, each at 10:90, 20:80, 30:70, 40:60, and 50:50). Investigation of the thermal and oxidative properties of esters from individual plant species and blended with soybean esters showed that the alternative esters are suitable for use as biodiesels. The chemical composition profile of transesterification products revealed a predominance of saturated compounds (62.5%) in S. phalerata oil, while a more balanced distribution between saturated (40.5%) and unsaturated (57.4%) esters was found for T. catappa, while a high unsaturated content (90.0%) was detected for A. moluccanus. Scheelea phalerata esters had a favorable effect on the blends, reducing thermal stability, decreasing crystallization points, and increasing induction periods. Higher ratios of T. catappa esters in the blends promoted an increase in thermal stability and crystallization points, while decreasing induction periods. Use of A. moluccanus esters in the blends led to increased thermal stability and decreased crystallization temperatures and induction periods.