Synthesis and Study of 4, 4-12-12 Alkyl Phenol Polyoxyethylene Sulfonate Gemini Surfactant

Background: Gemini surfactants have good prospect of application development in various fields for their superior performance in foaming, wettability, and emulsification with lower critical micelle concentration (CMC) than conventional mono-surfactants. Objective: The purpose of this study was to synthesize an ionic sulfonate Gemini surfactant, which is mainly used as an oil flooding agent, to improve oil recovery and reduce oil production cost. Methods: With 4-dodecyl phenol, diethylene glycol and triethylene glycol as the raw materials to synthesize two sulfonate Gemini surfactants. The single factor experiment combined with Box-Behnken center composite experimental design, the optimum reaction conditions were determined. The optimal reaction condition of sulfonation was determined by orthogonal test. The product structure was characterized by nuclear magnetic resonance and infrared. Results: The mass fraction of sodium hydroxide ω(NaOH), temperature and the quality ratio of hexadecyl trimethyl ammonium bromide to dodecyl phenol were 18%, 93.5°C and 14.2%, respectively. Under the condition of ice bath, the molar ratio of chlorosulfonic acid to 4, 4- 12-12 alkyl phenol polyoxyethylene ether was 2.02:1 and reaction for 5h. The critical micelle concentration was determined to be 2×10-4, 1.05×10-4, respectively. Conclusion: Two sulfonate Gemini surfactants, namely 5, 5-dilauryl alkyl-2,2'-(diethylene glycol oxygen base) sodium diphenyl sulfonate and 5,5-dilauryl alkyl-2,2'-(triethylene glycol oxygen base) sodium diphenyl sulfonate (recorded as III and IV, respectively) were synthesized. The synthesized surfactants have excellent emulsification ability.

A novel fluorometric assay for trypsin on the basis of a gemini anionic surfactant/BSA/NR supramolecular assembly system with favorable salt resistance

A novel label-free fluorometric assay for trypsin detection was successfully established on the basis of an anionic sulfonate gemini surfactant C12C3C12(SO3)2/bovine serum albumin (BSA)/nile red (NR) supramolecular assembly system.

Experimental Study of Sulfonate Gemini Surfactants as Thickeners for Clean Fracturing Fluids

Hydraulic fracturing is one of the important methods to improve oil and gas production. The performance of the fracturing fluid directly affects the success of hydraulic fracturing. The traditional cross-linked polymer fracturing fluid can cause secondary damage to oil and gas reservoirs due to the poor flow-back of the fracturing fluid, and existing conventional cleaning fracturing fluids have poor performance in high temperature. Therefore, this paper has carried out research on novel sulfonate Gemini surfactant cleaning fracturing fluids. The rheological properties of a series of sulfonate Gemini surfactant (DSm-s-m) solutions at different temperatures and constant shear rate (170 s−1) were tested for optimizing the temperature-resistance and thickening properties of anionic Gemini surfactants in clean fracturing fluid. At the same time, the microstructures of solutions were investigated by scanning electron microscope (SEM). The experimental results showed that the viscosity of the sulfonate Gemini surfactant solution varied with the spacer group and the hydrophobic chain at 65 °C and 170 s−1, wherein DS18-3-18 had excellent viscosity-increasing properties. Furthermore, the microstructure of 4 wt.% DS18-3-18 solution demonstrated that DS18-3-18 self-assembled into dense layered micelles, and the micelles intertwined with each other to form the network structure, promoting the increase in solution viscosity. Adding nano-MgO can increase the temperature-resistance of 4 wt.% DS18-3-18 solution, which indicated that the rod-like and close-packed layered micelles were beneficial to the improvement of the temperature-resistance and thickening performances of the DS18-3-18 solution. DS18-3-18 was not only easy to formulate, but also stable in all aspects. Due to its low molecular weight, the damage to the formation was close to zero and the insoluble residue was almost zero because of the absence of breaker, so it could be used as a thickener for clean fracturing fluids in tight reservoirs.