Synthesis, Characterization and Exploratory Application of Anionic Surfactant Fatty Acid Methyl Ester Sulfonate from Waste Cooking Oil

摘要

The environmentally friendly anionic surfactant fatty acid methyl ester sulfonate (MES) was prepared by esterification of waste cooking oil (WCO), a low-cost raw material, followed by sulfonation with chlorosulfonic acid. MES production from WCO (W-MES) gave yields up to 78 %. Such a value is only slightly lower than the one obtained from soybean oil (S-MES), 82 %, and almost the same as that from reused cooking oil (R-MES), 76 %. According to the two-phase titration results, the content of the active component, alpha-MES, in S-MES, R-MES and W-MES was equal to 76.82, 69.19 and 66.60 %, respectively. The disalt, RCH(CO2Na)SO3Na, contents were instead 3.2, 3.8 and 4.7 %, respectively. As proved by the results of the FTIR and NMR characterizations, the chemical structure of W-MES is almost the same as that of S-MES and R-MES. The critical micelle concentration of W-MES is 5.38 mmol/L and the corresponding surface tension is 32.3 mN/m. The hydrophile-lipophile balance value of W-MES is 12.33, which indicates that it can form oil/water emulsions. The three MES demonstrated the same adsorption efficiency, yielding a pC20 value of 3.22, and similar foam stability. Their detergency can be up to 75 % at a concentration of 400 mg/kg and the tolerance to Ca2+ is higher than the one exhibited by linear alkylbenzene sulphonic acid and alpha olefin sulfonate. Additionally, W-MES shows a considerable solubilization capacity towards polycyclic aromatic hydrocarbon as the molar solubilization ratios to pyrene, phenanthrene and acenaphthene in a 30 mmol/L solution are 1.22 x 10(-3), 2.67 x 10(-3) and 3.81 x 10(-3), respectively.