The Synthesis of Surfactants Using Transesterification Method for Enhancing Oil Recovery

Traditionally, petrochemical feedstock, which are expensive, non-renewable, and poorly biodegradable are used to create enhanced oil recovery (EOR) surfactants. This study used Soxhlet extraction, base-catalyzed transesterification, sodium bisulfite/CaO-catalyzed sulfonation, and neutralization to create methyl ester sulfonate (MES) surfactants from three inedible or understudied feedstocks: palm kernel oil (PKO), aloe vera oil, and neem oil. PKO, Aloe vera, and Neem had oil yields of 47.30%, 5.74%, and 8.58%, respectively. PKO had the highest methyl ester conversion (92.10%) and the lowest free fatty acid content. The order of MES synthesis yields, which tracked the quality of the precursor methyl esters, was PKO-MES (86.4%) > Aloe-MES (83.7%) > Neem-MES (81.5%). The successful sulfonation of all three surfactants was confirmed by Fourier-transform infrared spectroscopy, which showed the characteristic asymmetric and symmetric S=O stretching bands. PKO-MES showed the lowest minimum surface tension (31.8 mN/m), the highest foam stability (84.0%) and a favorable critical micelle concentration (0.28 g/L) and performed better than Aloe-MES and Neem-MES in most of the interfacial parameters. These findings demonstrate that palm kernel, Aloe vera and Neem oils can be converted into biodegradable, surface active MES surfactants with promising potential for sustainable, low-cost enhanced oil recovery with MES from PKO exhibiting the most favorable overall performance profile among the three feedstocks assessed.