The immiscibility of vegetable oil and alcohol during the initial step in biodiesel synthesis has slowed down the process resulting to increase production costs. Thus, process intensification techniques that would enhance mixing or molecular interactions of the reactants, and enable short reaction time should be carried out in order to increase yield and minimize costs. We proposed coupling of two process intensification schemes in enhancing molecular interactions, i.e. the use of supercritical carbon dioxide as a solvent and microfluidic device, as applied to esterification of oleic acid (OA) with methanol (MeOH). We found this superior over the commonly applied microwave. Hence, we further explored the influences of reaction temperature, OA-to-MeOH molar ratio, residence time, water contents, pressure and catalyst addition on the oleic acid methyl ester (OAME) yield. Results showed that at temperature range of 60 to 120 degrees C and pressure of 10 MPa, the esterification reaction proceeds even without any catalyst in less than 1 min. Addition of relatively small amount of catalyst (0.1 wt% H2SO4) dramatically increased the yield 4-fold to 90%. Recirculation of the product even without a catalyst significantly increased yield. The experimental analysis confirms the applicability potential of the microfluidic reactor in the non-catalytic biodiesel synthesis.