Extraction of Calophyllum oil as biodiesel raw material using a binary solvent

Abstract

The utilization of renewable raw material, low-cost feedstock, and efficient energy are the main parameters in sustainable biodiesel production. Calophyllum seeds are potential as a vegetable oil source for biodiesel production due to their high oil content and productivity. Calophyllum oil extraction is usually conducted by the mechanical press, but the yield and quality of oil produced by this method are very low. Calophyllum oil extraction using a binary solvent (a mixture of n-hexane and alcohol) was thus investigated to meet the aspects of sustainability and to solve the problem of mechanical extraction. The influence of extraction condition was examined to determine optimal oil yield and quality. The mixture of n-hexane and alcohol effectively extracts oil from Calophyllum seeds and simultaneously purified it from resin. The n-Hexane-to-alcohol ratio had a significant effect on oil recovery and its quality. The augmentation of the n-hexane-to-alcohol ratio from 1:1 to 2.5:1 increased oil yield. Acid value and density of oil improved as the n-hexane-to-alcohol ratio declined from 2.5:1 to 1:1. The n-Hexane-to-alcohol ratio of 2.5:1 has provided the best yield (88.0%) of oil extract at 40°C for 5 h. The oil present its best quality at 0.893 g/cm3 of density, 41.0 mPa.s of viscosity, 8.8 mg KOH/g of acid value, 88.3 g/100 g of iodine value, < 1% of moisture content and < 0.04% of ash content.