Study on the structure-activity relationship between the molecular structure of sulfate gemini surfactant and surface activity, thermodynamic properties and foam properties

Synthesis of new zwitterionic surfactants and investigation of their surface active and thermodynamic properties

This study focused on the synthesis of six bio-based zwitterionic surfactants derived from oleic acid to assess their applicability in different petroleum fields. The final bi-zwitterionic surfactants were synthesized from oleic acid, utilizing the double bond and carboxylic group. Friedel-Crafts alkylation, sulfonation, chlorination, amidation, and quaternization were performed to synthesize six bi-zwitterionic surfactants. The bi-quaternary surfactants derived from benzene are represented by the general formula Bi Q 10, BOAS (Amide), with the symbols BE, BP, and BPh. In contrast, those derived from naphthalene are represented by Bi Q 10, NOAS (Amide), with the symbols NE, NP, and NPh. The structures of these surfactants were confirmed using FT-IR and H1-NMR techniques. The surface activity and thermodynamic properties of the synthesized surfactants were analyzed through surface tension measurements conducted at various temperatures (30, 40, 50, and 60°C). Additionally, CMC, γCMC, πCMC, Γmax, Amin, and Pc20 were measured. The thermodynamic variables for micellization and adsorption were also measured. The structural effect of the obtained surfactants was assessed. The maximum value of the structural effect was 4.33 KJmol-1, corresponding to BE. The results indicated that the negative values of ΔGads were greater than the negative values of ΔGmic, indicating that these surfactants are absorbed in the interface prior to the formation of micelles. The more negative values of ΔGads suggest that these surfactants are strongly adsorbed onto solid particles, such as sands and rocks, indicating their potential utilization in oil production in different petroleum fields.

Exploring the Performance Advantages of p-Aminobenzenesulfonate-Based Zwitterionic Gemini Surfactants in Oil Recovery

To investigate the specific performance enhancement of oilfield surfactants by using sodium p-aminobenzenesulfonate as a connecting group, cationic surfactant N,N-dimethyl-N-(oxiran-2-ylmethyl)dodecan-1-aminium (DDPA) and zwitterionic gemini surfactant sodium 4-[bis(3-(dodecyldimethylamino)-2-hydroxypropyl)amino]benzenesulfonate (DDBS) were synthesized. The oil recovery performance of these surfactants was compared, revealing that DDBS outperforms DDPA in thermal stability, wettability, adsorption, and resistance to temperature and salinity variations, as well as surface/interface activity, except for emulsification. Core flooding experiments, simulating the conditions of the Xinjiang oilfield, demonstrated that DDBS can achieve the same enhanced oil recovery effect at a concentration that is 1/15 of that of DDPA. Compared with water, DDBS and DDPA can incrementally enhance recovery rates by 7.9% and 8.5%. Furthermore, the synergistic formulation of DDBS with sodium dodecylbenzenesulfonate (SDS) significantly optimized performance, achieving a reduction in interfacial tension to 0.0301 mN m-1. This study provides a research and data foundation for the application of new surfactants in petroleum extraction.

Formulation and characterization of surfactants with antibacterial and corrosion-inhibiting properties for enhancing shale gas drainage and production

A Gemini cationic surfactant was synthesized through an aldehyde-amine condensation reaction to address challenges related to bacterial corrosion and foaming during shale gas extraction. This treatment agent exhibits sterilization, corrosion mitigation, and foaming properties. The mechanism of action was characterized through tests measuring surface tension, particle size, sterilization efficacy, corrosion mitigation efficiency, and foaming behavior. Results from the surface tension test indicate that at 60 °C, surfactants with a low carbon chain structure achieve the lowest surface tension of 32.61 mN/m at the critical micelle concentration. Particle size distribution (PSD) tests reveal that within the 1-10 critical micelle concentration range, three types of surfactants can form aggregates through self-assembly, with a PSD range of 100-400 nm. Antibacterial performance tests demonstrate that a concentration of 0.12 mmol/L at 20-60 °C achieves a bactericidal rate exceeding 99%, maintained even after 24 h of contact. The bactericidal effect is enhanced under acidic and alkaline conditions. Corrosion mitigation tests show that at 50 °C, the corrosion mitigation rate reaches an optimal value of over 70%. Bubble performance evaluation results suggest that the optimal surfactant concentration is 1 mmol/L at 60 °C, exhibiting resistance to mineralization up to 200 g/L. The development of this surfactant establishes a foundation for effectively addressing issues related to bacterial corrosion and wellbore fluid encountered in shale gas wells.

Organo-Montmorillonite Modified by Gemini Quaternary Ammonium Surfactants with Different Counterions for Adsorption toward Phenol

The discharge of industrial phenol pollutants causes great harm to the natural environment and human health. In this study, phenol removal from water was studied via the adsorption of Na-montmorillonite (Na-Mt) modified by a series of Gemini quaternary ammonium surfactants with different counterions [(C₁₁H₂₃CONH(CH₂)₂N⁺ (CH₃)₂(CH₂)₂ N⁺(CH₃)₂ (CH₂)₂NHCOC₁₁H₂₃·2Y^-, Y = CH₃CO₃^-, C₆H₅COO^- and Br^-, 12-2-12·2Y^-]. The results of the phenol adsorption indicated that MMt-12-2-12·2Br^-, MMt-12-2-12·2CH₃CO₃^- and MMt-12-2-12·2C₆H₅COO^- reached the optimum adsorption capacity, which was 115.110 mg/g, 100.834 mg/g and 99.985 mg/g, respectively, under the conditions of the saturated intercalation concentration at 2.0 times that of the cation exchange capacity (CEC) of the original Na-Mt, 0.04 g of adsorbent and a pH = 10. The adsorption kinetics of all adsorption processes were in good agreement with the pseudo-second-order kinetics model, and the adsorption isotherm was better modeled by Freundlich isotherm. Thermodynamic parameters revealed that the adsorption of phenol was a physical, spontaneous and exothermic process. The results also showed that the counterions of the surfactant had a certain influence on the adsorption performance of MMt for phenol, especially the rigid structure, hydrophobicity, and hydration of the counterions.

Effects of Concentration of Soybean Protein Isolate and Maltose and Oil Phase Volume Fraction on Freeze-Thaw Stability of Pickering Emulsion

There is growing interest in enhancing the freeze-thaw stability of a Pickering emulsion to obtain a better taste in the frozen food field. A Pickering emulsion was prepared using a two-step homogenization method with soybean protein and maltose as raw materials. The outcomes showed that the freeze-thaw stability of the Pickering emulsion increased when prepared with an increase in soybean protein isolate (SPI) and maltose concentration. After three freeze-thaw treatments at 35 mg/mL, the Turbiscan Stability Index (TSI) value of the emulsion was the lowest. At this concentration, the surface hydrophobicity (H₀) of the composite particles was 33.6 and the interfacial tension was 44.34 mN/m. Furthermore, the rheological nature of the emulsions proved that the apparent viscosity and viscoelasticity of Pickering emulsions grew with a growing oil phase volume fraction and concentration. The maximum value was reached in the case of the oil phase volume fraction of 50% at a concentration of 35 mg/mL, the apparent viscosity was 18 Pa·s, the storage modulus of the emulsion was 575 Pa, and the loss modulus was 152 Pa. This research is significant for the production of freeze-thaw resistant products, and improvement of protein-stabilized emulsion products with high freeze-thaw stability.

Glutamic acid-glucose Gemini surfactants: physico-chemical properties and effect on the dyeability of polyester fabric

In this study we used glutamic acid as a linking group and glucose, propylene glycol, and fatty alcohols as raw materials to prepare glutamic acid-glucose Gemini surfactants. Fourier transform infrared spectroscopy was used to verify the structures of the surfactants. We investigated their surface properties (surface tension, contact angles), and their effect on the fluorescence of pyrene. To test their potential application, we prepared emulsions with the surfactants and olive oil, and evaluated the emulsion stability with a particle size analyzer. We also investigated the ability to dye polyester fabrics in the presence of the glutamic acid-glucose-gemini surfactants. Among our synthesized materials, those with shorter alkyl chains exhibited better surface activities and emulsification properties, resulting in excellent dye uptake and leveling.

Performance Evaluation and Mechanism Study of Seawater-Based Circulatory Fracturing Fluid Based on pH-Regulated WormLike Micelles

In this article, a novel salt-resistant pH-sensitive surfactant N-carboxystearamido methanesulfonic acid (MSA) was designed and synthesized. The rheological properties of the MSA/CTAB mixed system prepared using seawater were evaluated, and the variation laws of the related rheological parameters were discussed. The relevant fracturing technical parameters of the MSA/CTAB mixed system were comprehensively evaluated. The wormlike micelles formed by the non-covalent binding of MSA and CTAB molecules can resist the electrostatic effect of inorganic salts in the seawater. Meanwhile, the MSA/CTAB mixed system has an excellent pH response and revealed that the change from wormlike micelles to spherical micelles leads to the decrease of the apparent viscosity and the transition from Maxwell fluid to Newton-type fluid. Furthermore, the MSA/CTAB mixed system has excellent cyclic fracturing performance, which can meet the dual requirements of fracturing fluid cost and performance of offshore oilfield, and has a good application prospect.