Synthesis and Physicochemical Investigation of Anionic-nonionic Surfactants Based on Lignin for Application in Enhanced Oil Recovery

A series of eco-friendly anionic-nonionic surfactants lignin polyether sulfonates (LPES) based on alkali lignin from paper-making industry were prepared through alkoxylation, allylation and sulfonation reactions. The chemical structures of synthesized surfactants were determined by infrared spectrogram (IR) and 1H nuclear magnetic resonance (1H-NMR). In order to verify the adaptability of LPES surfactants applied in chemical enhanced oil recovery (EOR), the physicochemical properties including surface tension, salt tolerance, hydrophile lipophile balance (HLB) values and interfacial tension for LPES surfactants were investigated through experiments. The critical micelle concentration (cmc) of LPES surfactants increased with the growth of EO groups in molecules and the corresponding surface tension values were about 32~38 mN/m. Salt tolerance measurements prove that the LPES surfactants have a high tolerance to Na+ and Ca2+, and the HLB measurements demonstrate that the LPES surfactants have excellent emul...