Characterization of coconut oil (Cocos nucifera L.) from fresh and waste coconut pulp for biodiesel production via transesterification process

Abstract

As the demand of the fossil fuel is high but limited resource availability, biodiesel has become one of the alternatives fuels since it can be produced from renewable sources such as vegetable oil. Coconut oil is one of promising resource due to its high availability, low cost and non-toxic. In this study, coconut oil was extracted using Soxhlet extraction, where oil yield from fresh coconut oil contains 61.26% of extractable oil, meanwhile coconut oil from waste coconut pulp that has been squeezes for one and three times contain 51.66% and 17.08% of yield oil, respectively. According to the characteristic properties results, the moisture content of coconut oil was found to be around 0.67-1.10%, pH value of 5.43-6.51, FFA value of 0.39-7.07%, acid value of 0.78-14.07mg/g and saponification value of 220.71-241.91mgKOH/g. Meanwhile, for biodiesel, the moisture content is 5.57-5.70%, pH value of 5.12-5.62, FFA value of 0.38-0.39%, acid value of 0.75-0.78mg/g and saponification value of 218.21-223.06mgKOH/g. The identification functional group of coconut oil and biodiesel oil was done using FTIR. The peaks observed in biodiesel oil at 2922-2923cm-1 is associated with stretching sp3 -CH in the functional group of -CO-O-CH3. Meanwhile, peak at 1742-1743cm-1 shows the stretching C=O which commonly found in fatty acid methyl esters (FAME), and at the peak of 1153 cm-1 attributes to C-O in ester compound. The broad peak at 3326 cm-1 from biodiesel oil indicates the presence of -OH compound. According to the result, fresh and waste 1X coconut oil is suitable to be used in direct transesterification process, meanwhile for waste 3X coconut oil, acid esterification process is required before transesterification process.