Homogeneous catalysed biodiesel synthesis from Alexandrian Laurel (Calophyllum inophyllum L.) kernel oil using ortho-phosphoric acid as a pretreatment catalyst

ABSTRACT

In this study, a non-edible seed oil of Alexandrian Laurel (Calophyllum inophyllum L.) with higher free fatty acid content has been harnessed to produce biodiesel by transesterification process. The 20.2% free fatty acid (FFA) content was first reduced to 12.9% by using TOP degumming process. Ortho-phosphoric acid was used to esterify the refined kernel oil. Transesterification reaction was performed with NaOH as an alkaline catalyst and methanol as an analytical solvent. The effects of methanol to oil molar ratio (MR), catalyst concentration (CC), reaction temperature (TP), reaction time (TM), and stirrer speed (SS) on biodiesel conversion were studied to optimize the transesterification conditions using DOE- approach. The experimental study revealed that 9:1 MR, 0.8 wt.% CC, 60°C TP, 75 min TM and 1000 rpm SS were the optimal process control variables. The study indicated that CC was the most important control parameter in optimal methyl ester production. The optimal treatment combination yielded 97.14% of biodiesel. The profile of biodiesel was determined using gas chromatography-mass spectrometry. ¹H NMR spectrum of Calophyllum inophyllum methyl ester (CIME) has been reported. The properties of the biodiesel have been found within specifications of the ASTM D6751 and EN 14214 standards and hence could be considered as a suitable alternative to diesel fuel for sustainable circulation of carbon.

KEYWORDS:

• Biodiesel analysis
• DOE-approach
• non-edible oil
• TOP degumming
• transesterification

Acknowledgments

The authors thank the Director, National Institute of Technology, Tiruchirappalli, India and the Director, Central Electro-Chemical Research Institute (CECRI), Karaikudi, India for extending the facilities to carry out the work.