Anionic fatty acid methyl ester sulfonate (MES), an unconventional biosurfactant to replace the petroleum-based surfactant, was synthesized via transesterification of used cooking oil (UCO) followed by sulfonation with sodium bisulfite (NaHSO₃). The MES production process variables (sulfonation temperature, sulfonation time, and sulfonating agent/methyl ester (ME) molar ratio) were optimized to evaluate their effects on the MES yield and surface tension using central composite design (CCD). Based on the CCD, second-order polynomial response models were developed and used to correlate the sulfonation process parameters and the two responses. While the FAME content in the intermediate product (ME) was qualitatively analyzed by GC-FID, MES was characterized by FTIR, NMR, and surface tension analyses. Results from the GC-FID analysis revealed a total of 19.3% saturated and 76.36% unsaturated FAME contents in the intermediate product. The models were satisfactory for the sulfonation process with high coefficients of determination (R² = 0.9683 and Adj-R² = 0.9113) and (R² = 0.9678 and Adj-R² = 0.9097) for MES yield and surface tension, respectively. The optimum sulfonation conditions for synthesized MES from UCO were obtained to be 101.38 °C sulfonation temperature, 3.06 h sulfonation time, and 1:1 NaHSO₃/ME molar ratio, which resulted in MES yield and surface tension of 67.03% and 25.09 mN/m, respectively. As revealed by the FTIR and NMR analyses, methyl (CH₃ and CH₂), sulfonate (S = O and S–O), and esters (C = O, C–O, and –OCH₃) groups were confirmed in the synthesized product, thus suggesting the target MES product. The critical micelle concentration of MES and the corresponding surface tension were 128 mg/L and 31.5 mN/m, respectively.

阴离子脂肪酸甲酯磺酸盐 (MES) 是一种替代石油基表面活性剂的非常规生物表面活性剂，通过将使用过的食用油 (UCO) 进行酯交换，然后用亚硫酸氢钠 (NaHSO ₃）。优化 MES 生产过程变量（磺化温度、磺化时间和磺化剂/甲酯 (ME) 摩尔比），以使用中心复合设计 (CCD) 评估它们对 MES 产率和表面张力的影响。基于CCD，二阶多项式响应模型被开发并用于关联磺化工艺参数和两个响应。中间产物 (ME) 中的 FAME 含量通过 GC-FID 进行定性分析，而 MES 则通过 FTIR、NMR 和表面张力分析进行表征。GC-FID 分析的结果显示，中间产物中总共含有 19.3% 的饱和 FAME 和 76.36% 的不饱和 FAME。该模型对于磺化过程令人满意，具有高决定系数（R ²  = 0.9683 和 Adj-R²  = 0.9113) 和 (R ²  = 0.9678 和 Adj-R ²  = 0.9097) 分别用于 MES 屈服和表面张力。UCO合成MES的最佳磺化条件为101.38 °C磺化温度、3.06 h磺化时间和1:1 NaHSO ₃ /ME摩尔比，MES产率和表面张力分别为67.03%和25.09 mN/ m，分别。FTIR 和 NMR 分析表明，甲基（CH ₃和 CH ₂）、磺酸盐（S = O 和 S-O）和酯（C = O、C-O 和 -OCH ₃) 基团在合成产品中得到确认，从而表明目标 MES 产品。MES 的临界胶束浓度和相应的表面张力分别为 128 mg/L 和 31.5 mN/m。