Effect of different hydrophilic heads on strong interfacial activities of non-edible oil-derived ultra-long chain (UC24:1) Bio-based zwitterionic surfactants for tertiary oil recovery

One of the cross -cutting issues in green petrochemistry is discovering an efficient and sustainable technique for chemically enhanced oil recovery (EOR). Developing eco-friendly and renewable surfactants with strong interfacial activity as greener chemical materials for EOR has been a challenging topic. In this work, a new series of eco-friendly and high -performance ultra-long chain fatty acid-derived bio -based zwitterionic surfactants with different hydrophilic heads (the 2-(dimethyl(3-(tetracos-15-enamido)propyl)ammonio)acetate (TAPAA), 3(dimethyl(3-(tetracos-15-enamido)propyl)ammonio)- 2-hydroxypropane-1-sulfonate (TAPAHPS), and 4(dimethyl(3-(tetracos-15-enamido)propyl)ammonio)butane-1-sulfonate (TAPABS)), was developed from the non-edible fatty acid (Z)- 15-tetracosenoic acid (UC24:1) by a simple and effective method. ESI -MS, 1HNMR, and 13C NMR were used for their structural analyses. In alkali- and polymer-free systems, 0.5 g/L concentration of each surfactant could reduce the interfacial tension between Daqing crude oil and simulated formation groundwater to ultra-low value (1.971 x 10-3, 4.44 x 10-3 and 6.538 x 10-4 mN/m for TAPAA, TAPAHPS and TAPABS, respectively). These surfactants also demonstrated strong electrolyte tolerance, up to 2000 mg/L and 200 g/L of Ca2+ and NaCl, respectively. They were also structurally thermal stable up to 75 degrees C and biodegradable. This work consolidates our hypothesis that ultra -long chain (UC24:1) bio-based zwitterionic surfactants are of greater use than short -chain surfactants or traditional alkali -surfactant -polymer (ASP) systems for EOR applications, as they show strong interfacial activity at lower dosages in alkali- and polymer -free systems.