Gemini quaternary ammonium salt surfactant, also known as cationic Gemini surfactant, is a new type of surfactant that connects two or more single-chain cationic surfactants through a linking group. Gemini quaternary ammonium salt surfactant's special double N head group molecular structure gives it unique physical and chemical properties. Compared with traditional single quaternary ammonium salt, it has more excellent surface/interface activity, bacteriostasis and unique rheological behavior. And it has the advantages of good wettability and strong emulsifying ability.
Gemini quaternary ammonium salt surfactants currently have great application value in the fields of sterilization and disinfection, oil fields, metal corrosion inhibition, textile printing and dyeing, sewage treatment, and new materials, and have received widespread attention.
Application in the field of sterilization
Since the gemini quaternary ammonium salt surfactant contains two positively charged hydrophilic groups and two hydrophobic chains, it has stronger properties than traditional single-chain quaternary ammonium salts (Dodecyl trimethyl ammonium chloride and Dodecyl dimethyl benzyl ammonium chloride). The ability to kill bacteria, and has low toxicity, wide biological activity and good water solubility.
①It has great application value in the field of sterilization and anti-corrosion in personal care products, cosmetics and papermaking industries; ②It can be used as a high-efficiency bactericide for industrial cooling circulating water to reduce pipeline blockage and equipment corrosion; ③Tertiary oil recovery in oilfields as corrosion inhibitor Alternatives to bactericides (Dodecyl dimethyl benzyl ammonium chloride), reduce the corrosion of bacteria (sulfate reducing bacteria, iron bacteria, saprophytes, etc.) on petroleum pipelines and solve the problem of bacterial resistance.
Sterilization mechanism of Gemini quaternary ammonium salt surfactant:
① Gemini quaternary ammonium salt surfactants have two hydrophobic chains in the molecular structure, which is beneficial for the hydrophobic base to penetrate into the lipid layer of the bacterial cells and the hydrophilic base to penetrate into the protein layer, resulting in enzyme inactivation and protein denaturation; ② Molecular structure It contains two N head groups, and the positive charge density of Gemini quaternary ammonium salt head groups increases under the induction action, which makes it easier for the surfactant to adsorb on the surface of the bacteria, changes the permeability of the bacterial cell wall and ruptures it, achieving the effect of killing bacteria .
Research by Zhao Jianxi and others showed that the bactericidal effect of Gemini quaternary ammonium salt surfactant is significantly better than that of traditional quaternary ammonium salt. When the killing effect on Staphylococcus aureus and E. coli is the same, the usage amount of Gemini quaternary ammonium salt surfactant It is 1/25 of the latter, and the amount used to kill Candida albicans is only 1/40 of the latter, showing highly effective bactericidal properties.
In the field of sterilization in the petroleum industry, Liu Qingwang and others studied the effects of Gemini quaternary ammonium salt (16-4-16), Dodecyl dimethyl benzyl ammonium chloride and Methylisothiazolinone on sulfate-reducing bacteria, iron bacteria and saprophytes. It was found that the killing effects of the three fungicides all reached the standard, but the gemini quaternary ammonium salt surfactants had better killing effects and could reduce bacterial resistance.
Application in tertiary oil recovery
Used as a clean fracturing fluid in oil fields
Fracturing fluid is a working fluid used for fracturing and reforming oil and gas formations. Its main function is to transfer the ground pressure to the formation to form fractures and transport proppant. Traditional fracturing agents, guar gum, hydroxyethyl cellulose and other high-molecular polymers will leave residues in the fractures and damage the formation, resulting in reduced formation seepage capacity and productivity. Gemini quaternary ammonium salt surfactants have a good application prospect in viscoelastic surfactant fracturing fluids (VES) because of their unique rheology and low damage.
Jia Zhenfu and others researched and prepared a new type of Gemini quaternary ammonium salt surfactant: bis-18 alkyl-tetraol ethyl-dibromoethylenediamine, and other adjuvants to prepare a new clean fracturing fluid system. The system has good viscoelasticity, sand suspension performance, low temperature solubility and temperature stability. This fracturing fluid has been put into use in CNOOC Bohai Petroleum.
Zhu Hongjun et al. prepared a clean fracturing fluid using long-carbon chain hydroxyl-containing gemini quaternary ammonium salt as an acid thickener. The results showed that the fracturing fluid has good thermal stability, shear resistance, slow speed, and salt resistance. , Gel breaking performance, used in acid fracturing operations can effectively improve the fracturing effect and increase the efficiency of fracturing. It is an ideal clean fracturing fluid.
Chemical depressurization of water injection wells
After long-term water injection in the water injection well, the reservoir is seriously blocked due to fluid resistance, water lock damage, clay migration, formation scaling, and the proliferation of bacteria. This problem is particularly prominent in the area near the well, resulting in water injection pressure. It stays high and the water injection is seriously insufficient.
The chemical method of depressurization and augmentation is mainly by injecting the decompression and augmentation agent containing Gemini quaternary ammonium salt into the water well to reduce the oil-water interfacial tension, reduce the Jiamin effect, and increase the oil flow capacity; change the wettability of the rock surface to make the oil reservoir More hydrophilic, exerting the effect of capillary force; inhibiting clay expansion and reducing damage to the formation; inhibiting the growth of microorganisms and reducing damage to the bottom of the well and formation; improving the permeability of injected water to achieve the purpose of reducing pressure and increasing injection in low-permeability oil fields . In addition, the depressurization and injection enhancement technology has a certain oil displacement effect.
Fu Yarong selected the Jin 95 station crude oil and Jin 95-2 well to inject water, and performed the depressurization and injection enhancement simulation experiment on the depressurization and injection enhancement agent FYR-ZZ containing surfactant. The results show that after the application of the depressurization enhancing agent for water injection wells, the water injection volume is increased, the water injection pressure is reduced, the load of the water injection pump is reduced, the safety factor of the water injection pipeline is improved, and there is a certain increase effect, and the injection pressure of the water injection well is reduced. , Saving power.
Used as high-efficiency chemical oil displacement agent in tertiary oil recovery
Gemini quaternary ammonium salts have better surface activity and lower critical micelle concentration than traditional single-chain quaternary ammonium salts, and can form flexible linear micelles at very low concentrations and entangle each other to form a network structure. The viscosity of the solution is greatly increased and has the characteristics of thinning. The special rheological properties can effectively change the oil-water mobility ratio, expand the swept volume, and improve the oil displacement efficiency. Injecting a solution system containing this type of gemini quaternary ammonium salt into the formation can not only greatly reduce the oil-water interfacial tension (up to 10-3 mN/m), change the oil rheology and emulsification, but also improve the wettability of the formation surface ( Wetting reversal occurs), reducing the adhesion of oil to the surface of the formation, and greatly improving the oil washing ability; it can also form a relatively stable oil-water emulsion, making it easier to flow and produce.
Fan Zhenzhong’s research team studied the oil displacement efficiency of three gemini quaternary ammonium salts (mnm type). The core displacement results show that the combination of such gemini quaternary ammonium salts and common surfactants can greatly improve the oil recovery. Become an efficient displacing agent for tertiary oil recovery.
Fluid energy-saving drag reducer
With the growth of the global economy, mankind is facing a more and more profound energy crisis. How to reduce the frictional resistance of the flow in the process of long-distance pipeline fluid transportation and reduce the power consumption of pumping stations is an important aspect of the development of energy-saving and drag-reducing technologies. ring.
Adding fluid chemical drag reducers can greatly reduce the resistance of the flow process and reduce the consumption of the pump. This phenomenon is called the Toms effect. The most commonly used drag reducers are polymers and surfactants. Polymers are prone to chain rupture under the mechanical shearing of the pump, which weakens the drag reduction performance and is not suitable for closed-circuit circulation systems. Surfactant micelles have self-assembly properties, can spontaneously return to a sheared structure after high-speed shearing, have good reversibility, and are suitable for both circulating and non-circulating fluid transport systems. Compared with traditional surfactants, Gemini surfactants have more excellent surface activity and self-assembly characteristics, and have great application value in fluid drag reduction systems.
Fang Bo studied the rheology and drag reduction properties of a micellar system composed of gemini quaternary ammonium salt surfactants (C18-3-C18 type) and sodium salicylate. The results show that the micellar system can effectively reduce the flow friction resistance of straight pipes, which is far better than the traditional single-chain quaternary ammonium salt CTAC/sodium salicylate micellar system.
Application in the field of metal corrosion inhibition
Metal corrosion can change the mechanical and physical and chemical properties of metal materials and cause great economic losses to industrial production and living facilities. Gemini quaternary ammonium salt surfactants show more outstanding performance in metal corrosion resistance than traditional single-chain quaternary ammonium salts, and have high efficiency and non-toxic characteristics. It can make the hydrophobic chain form a dense adsorption film on the metal surface through the strong electrostatic attraction of its double N head group, which significantly reduces the corrosion behavior of the metal in the chemical medium. At present, it is widely used in petrochemical, transportation, steel and machinery fields.
Surface active agent metal corrosion inhibition mechanism: metal surface is generally negatively charged. Gemini quaternary ammonium salt surfactant dissociates into two charged cations in water after being dissolved in water. Gemini quaternary ammonium salt surfactant ions are adsorbed by electrostatic attraction On the metal surface, the hydrophobic group can form a dense hydrophobic film on the metal surface, which can well isolate the contact of water or other anti-corrosive substances with the metal, so as to achieve the purpose of high-efficiency metal corrosion inhibition.
Gao Zhinong et al. studied the anti-corrosion effect of a series of gemini quaternary ammonium salt surfactants (m-n-m type) on aluminum in 1 mM HCl medium. The results show that this kind of gemini quaternary ammonium salt has excellent anti-corrosion effect on aluminum in acidic medium, and has the best anti-corrosion effect under the critical micelle concentration. Further experiments show that this kind of gemini quaternary ammonium salt has high anti-corrosion effect on various metals, and has extremely high application value of metal corrosion inhibition.
Li Jun et al. studied the corrosion inhibition effect of a series of hydroxypropyl gemini quaternary ammonium salts (Cn-3OH-Cn) on L360 steel in H2S/CO2 corrosive media. The results show that the corrosion inhibition rate reaches more than 95% when the concentration is 35 mg/L. It is a mixed type corrosion inhibitor that mainly suppresses the cathode.
Application in textile printing and dyeing industry
It can be used as an alkali reduction accelerator for polyester fabric and a cationic dye retardant
Gemini quaternary ammonium salt can obviously promote the alkali reduction treatment of polyester fabric. The strength loss of the treated fabric is small, and the drape, air permeability and moisture retention rate of the fabric can be effectively improved. The fiber treated with cationic dye is crystallized The temperature and glass transition temperature are low, and the internal structure of the fiber is relatively loose, so the adsorption rate is faster. The gemini quaternary ammonium salt added to the dye first enters the fiber and combines with the sulfonic acid anion, and then replaces it after the cationic dye enters, thereby slowing the dye adsorption rate and achieving a slow dyeing effect.
Wang Rongxiang et al. applied gemini quaternary ammonium salt (mnm type) to polyester fabric alkali reduction accelerator and retarder, and found that this type of gemini quaternary ammonium salt has a significant effect on the alkali reduction treatment of polyester fabric, and the fabric performance after finishing is good , Performance is significantly better than traditional single-chain quaternary ammonium salt.
Can be used to improve pitting in nylon printing
Nylon is prone to pitting on the surface when printing acid dyes, which manifests as local aggregation on the surface of the fabric. By adding appropriate gemini quaternary ammonium salts, anionic dyes and gemini quaternary ammonium salts form a spatial network structure on the cloth surface, making the dyes difficult to move during the lifting or drying process of the printing table, and preventing the occurrence of textile pits. The stable interaction between gemini quaternary ammonium salts and acid dyes is beneficial to reduce the occurrence of printing pits.
Studies have shown that when hydroxyl-containing gemini quaternary ammonium salt is used in combination with other additives, it can eliminate the pitting caused by dyes in nylon printing.
Low-salt technology in the dyeing process of cotton and linen fabric
The use of a large amount of inorganic salts in the dyeing process of cotton fabrics has brought great difficulties to sewage treatment. Salt-free/low-salt/alkali dyeing has become a research hotspot. Modification of cotton fiber with a small amount of gemini quaternary ammonium salt and then delayed dyeing with reactive dyes can greatly reduce the amount of inorganic salt, which is beneficial to reduce costs, reduce salt pollution to the environment, and improve product quality.
Jia Lihua et al. used ester gemini quaternary ammonium salt as an auxiliary agent to dye linen fabrics with reactive dyes. The dye uptake and fixation rate of reactive yellow M-3RE reached more than 85%. This type of gemini quaternary ammonium salt treated linen fabrics The dyeing performance is better than traditional quaternary ammonium salt-CTAB, and the coloring rate and fixing rate are increased by nearly 10%.
Application in sewage treatment
Gemini quaternary ammonium salt has a strong adsorption effect compared with traditional quaternary ammonium salt, so it is often used as an adsorbent to clean up pollutants in liquids. The treatment of sewage with surfactants first needs to adsorb the surfactants on a medium such as clay or sand, and then use the latter to adsorb pollutants. This is an effective means of pollution control.
Liu Xuemin’s research group used amido gemini quaternary ammonium salt as an organic intercalant to modify montmorillonite. The results showed that the gemini quaternary ammonium salt was successfully inserted between the montmorillonite layers, and the modified montmorillonite was resistant to chlorine in the water. The adsorption capacity of phenol is 6 times that of unmodified original soil, and it shows good application value for the removal of organic matter in wastewater.
Rosen et al. studied the adsorption of 2-naphthol on traditional quaternary ammonium salts and gemini quaternary ammonium salts. It was found that the adsorption capacity of 2-naphthol by montmorillonite with gemini quaternary ammonium salt was 15 times that of traditional quaternary ammonium salt-modified montmorillonite. Sand and limestone with gemini quaternary ammonium salt were traditional 3 times, Gemini quaternary ammonium salt has the characteristics of larger adsorption capacity and higher efficiency than traditional quaternary ammonium salt.
Preparation of new mesoporous materials
Mesoporous molecular sieves have large controllable pore sizes and high specific surface areas, and are currently widely used in the fields of catalytic cracking, separation and nanoscience of petroleum. Gemini quaternary ammonium salt can form a variety of special structure aggregates in aqueous solution due to its structural variability. It can act as a template during the preparation of mesoporous materials. Therefore, it can control the alkyl chain of gemini quaternary ammonium salt. The length, length and type of the linking group are used to prepare silicate molecular sieves with different crystal phases and different pore sizes. Compared with traditional single-chain quaternary ammonium salts, Gemini quaternary ammonium salt has very little usage and lower cost.
Vander Voort et al. can prepare mesoporous materials with different crystal shapes by adjusting the length of the linking group of the gemini quaternary ammonium salt (m-n-m type). When n=10,12, MCM-48 molecular sieve can be prepared; when n is small, it is suitable for preparing MCM-41.
Hu Jun et al. used the flexible linking group gemini quaternary ammonium salt and the rigid linking group gemini quaternary ammonium salt as templates to study the influence of the linking group on the silicon-based mesoporous materials. When the linking group is a flexible methylene group, the result is consistent with Vander Voort; when the linking group contains a hydroxyl group, a layered material structure can be prepared; when the linking chain contains a rigid benzene ring, a hollow spherical structure material can be obtained.
Gemini quaternary ammonium salt's special molecular structure and excellent surface/interface properties make it used as an antistatic agent for fabrics. In the paper industry, it can be used as an anti-mold bactericide, fiber dispersant, waste paper deinking agent and antistatic agent, etc. .