Process Optimization of Solvent-Free Transesterification of Palm Kernel Oil for Biodiesel Production

Abstract

This study investigates the production of biodiesel as a sustainable alternative fuel to 
enhance global energy security. Biodiesel was synthesized from palm kernel oil through 
NaOH-catalyzed transesterification in the presence of cellulose as an auxiliary material. 
Systematic process optimization was conducted to determine the conditions that maximize 
product yield. The optimum parameters were identified as a reaction temperature of 140 
°C, reaction time of 7 h, catalyst loading of 0.4 g NaOH, cellulose loading of 0.5 g, and 
agitation speed of 800 rpm, under which a maximum biodiesel yield of 92.85% was achieved. 
Comprehensive physicochemical characterization of the product was performed using 
Fourier Transform Infrared Spectroscopy (FT-IR), Gas Chromatography–Mass 
Spectrometry (GC-MS), Thermogravimetric Analysis (TGA), and Nuclear Magnetic 
Resonance (NMR) spectroscopy. The analytical results confirmed the successful conversion 
of triglycerides to fatty acid methyl esters (FAME), the principal constituents of biodiesel. 
Thermal analysis indicated good thermal stability up to approximately 240 °C, while 
compositional and structural data demonstrated compliance with established international 
biodiesel specifications, specifically ASTM D6751-07b and EN 14214:2003 standards. 
Engine performance testing showed that the produced biodiesel could effectively power a 
conventional diesel engine without operational difficulties. Additionally, the biodiesel 
exhibited immiscibility with water, indicating favorable storage and handling 
characteristics. Beyond its primary application as a renewable transportation fuel, the 
physicochemical properties of the product suggest potential utility as a functional additive 
in surface coating formulations and decorative materials. Overall, the findings demonstrate 
that palm kernel oil is a viable feedstock for high-yield biodiesel production under optimized 
conditions, supporting its role in sustainable energy diversification.