Industrial applications of gemini quaternary ammonium salt surfactants

Gemini quaternary ammonium salt surfactants, also known as cationic Gemini surfactants, are a new type of surfactant that links two or more single-chain cationic surfactants together through linking groups. The unique double N-headed molecular structure of Gemini quaternary ammonium salt surfactants endows them with unique physicochemical properties. Compared to traditional single-chain quaternary ammonium salts, they exhibit superior surface/interfacial activity, antibacterial and bactericidal properties, and unique rheological behavior, as well as advantages such as good wetting properties and strong emulsifying ability.
Gemini quaternary ammonium salt surfactants currently have significant application value and have gained widespread attention in fields such as sterilization and disinfection, oil fields, metal corrosion inhibition, textile printing and dyeing, wastewater treatment, and new materials.
1. Applications in the field of sterilization and disinfection
: Because Gemini quaternary ammonium salt surfactant molecules contain two positively charged hydrophilic groups and two hydrophobic chains, they have a stronger bactericidal ability compared to traditional single-chain quaternary ammonium salts (1231 and 1227), and also possess low toxicity, broad-spectrum biological activity, and good water solubility.
Application Areas:
① It has significant application value in sterilization and preservation in personal care products, cosmetics, and the paper industry;
② It can be used as a highly efficient bactericide for industrial cooling circulating water, reducing pipe blockage and equipment corrosion;
③ In tertiary oil recovery, it can be used as a substitute for corrosion inhibitors (1227), reducing the corrosion of oil pipelines by bacteria (sulfate-reducing bacteria, iron bacteria, and saprophytic bacteria, etc.) and solving the problem of bacterial resistance.
Mechanism of Sterilization and Disinfection of Gemini Quaternary Ammonium Salt Surfactants:
① The molecular structure of gemini quaternary ammonium salt surfactants contains two hydrophobic chains, which facilitates the penetration of hydrophobic groups into the lipid layer of bacterial cells and hydrophilic groups into the protein layer, leading to enzyme inactivation and protein denaturation;
② The molecular structure contains two N-head groups, which, under induction, increase the positive charge density of the gemini quaternary ammonium salt head groups, making it easier for the surfactant to adsorb onto the bacterial surface, altering the bacterial cell wall permeability and causing it to rupture, thus achieving the effect of killing bacteria.
Literature Examples:
Research by Zhao Jianxi et al. shows that gemini quaternary ammonium salt surfactants have significantly better bactericidal effects than traditional quaternary ammonium salts. When the bactericidal effects against Staphylococcus aureus and Escherichia coli are the same, the amount of gemini quaternary ammonium salt surfactant used is only 1/25 of that used against Escherichia coli, and the amount used to kill Candida albicans is only 1/40 of that used against Escherichia coli, demonstrating highly efficient bactericidal properties.
In the field of disinfection in the petroleum industry, Liu Qingwang et al. studied the bactericidal effects of gemini quaternary ammonium salts (16-4-16), 1227, and isothiazolinones against sulfate-reducing bacteria, iron bacteria, and saprophytic bacteria. The results showed that the bactericidal effects of all three bactericides met the standards, but gemini quaternary ammonium salt surfactants had a better bactericidal effect and could reduce bacterial resistance.

2. Application in Tertiary Oil Recovery
2.1 Use as a Clean Fracturing Fluid in Oilfields

Fracturing fluid is the working fluid used during fracturing of oil and gas reservoirs. Its main function is to deliver proppant by transmitting high surface pressure to the formation, creating fractures. Traditional fracturing agents, such as guar gum and hydroxyethyl cellulose, leave residues in the fractures, damaging the formation and reducing its permeability and productivity. Gemini quaternary ammonium salt surfactants, due to their unique rheological properties and low harmfulness, show promising application prospects in viscoelastic surfactant fracturing fluids (VES).
Literature example:
Jia Zhenfu et al. prepared a novel gemini quaternary ammonium salt surfactant: bis(18alkyl-tetraolethyl-dibromoethylenediamine), and other additives to prepare a new clean fracturing fluid system. This system exhibits good viscoelasticity, sand-suspending properties, low-temperature solubility, and temperature stability. This fracturing fluid has already been put into use at CNOOC Bohai Oilfield.
Zhu Hongjun et al. prepared a clean fracturing fluid using long-chain hydroxyl-containing gemini qua-ternary ammonium salts as acid thickeners. Results showed that this fracturing fluid possessed good thermal stability, shear resistance, slowing effect, salt resistance, and gel breaking properties. Its use in acid fracturing operations effectively improved fracturing performance and increased fracturing efficiency, making it an ideal clean fracturing fluid.
2.2 Chemical Pressure Reduction and Injection Enhancement in Water Injection
Wells: After long-term water injection, water injection wells suffer from severe reservoir blockage due to liquid resistance, water lock damage, clay migration, formation scaling, and the proliferation of bacteria. This problem is particularly prominent in the near-wellbore zone, resulting in persistently high injection pressure and insufficient injection volume.
Chemical depressurization and injection enhancement mainly involves injecting depressurization and injection enhancement agents containing geminal quaternary ammonium salts into water wells to reduce the interfacial tension between oil and water, reduce the Jamin effect, and increase oil flowability; altering the wettability of rock surfaces, making the reservoir more hydrophilic and exerting capillary force; inhibiting clay swelling, reducing damage to the formation; inhibiting microbial growth, reducing damage to the well bottom and formation; and improving the permeability of injected water, achieving the goal of depressurization and injection enhancement in low-permeability oilfields. Furthermore, this depressurization and injection enhancement technology has a certain oil displacement effect.
Literature example:
Fu Yarong used crude oil from Jin 95 station and injection water from Jin 95-2 well to conduct a depressurization and injection enhancement simulation experiment using the surfactant-containing depressurization and injection enhancement agent FYR-ZZ. The results showed that after applying the depressurization and injection enhancement agent to the injection well, the injection volume increased, the injection pressure decreased, the injection pump load was reduced, the safety factor of the injection pipeline was improved, and it also had a certain enhancement effect. Furthermore, the reduction in injection pressure saved electrical energy.
2.3 Used as a high-efficiency chemical oil displacement agent in tertiary oil recovery .

Gemini quaternary ammonium salts exhibit better surface activity and lower critical micelle concentrations compared to traditional single-chain quaternary ammonium salts. They can form flexible linear micelles at extremely low concentrations, which then intertwine to form a network structure, significantly increasing solution viscosity and exhibiting shearing characteristics. Their unique rheological properties can effectively alter the oil-water mobility ratio, expand the swept volume, and improve oil displacement efficiency. Injecting solutions containing these gemini quaternary ammonium salts into formations can not only greatly reduce the oil-water interfacial tension (reaching 10⁻³ mN/m), altering the rheology and emulsification of oil, but also improve formation surface wettability (causing wetting reversal), reducing oil adhesion to the formation surface, and significantly enhancing oil washing capacity. Furthermore, they can form relatively stable oil-water emulsions, facilitating flow and extraction.
Literature example:
Fan Zhenzhong’s research group studied the oil displacement efficiency of three types of gemini quaternary ammonium salts (mnm type). Core displacement results showed that these gemini quaternary ammonium salts, when combined with common surfactants, can significantly improve oil recovery and can serve as highly efficient displacement agents for tertiary oil recovery.
3. Fluid Energy Saving and Drag Reduction Agents
With global economic growth, humanity faces an increasingly profound energy crisis. Reducing flow friction and power consumption in long-distance pipeline fluid transportation is a crucial aspect of energy saving and drag reduction technology development.
Adding fluid chemical drag reduction agents can significantly reduce flow resistance and pump consumption; this phenomenon is known as the Toms effect. Currently, the most commonly used drag reduction agents are polymers and surfactants. Polymers are prone to chain breakage under the mechanical shearing of pumps, weakening their drag reduction performance and making them unsuitable for closed-loop circulation systems. Surfactant micelles possess self-assembly properties, spontaneously recovering to their sheared structure after high-speed shearing, exhibiting good reversibility and applicable to both circulating and non-circulating fluid transportation systems. Compared to traditional surfactants, gemini surfactants have superior surface activity and self-assembly characteristics, making them highly valuable in fluid drag reduction systems.
Literature Example:
Fang Bo studied the rheological and drag reduction properties of a micelle system composed of gemini quaternary ammonium salt surfactants (C18-3-C18 type) and sodium salicylate. The results show that this micelle system can effectively reduce the frictional resistance of straight pipe flow, which is far superior to the traditional single-chain quaternary ammonium salt CTAC/sodium salicylate micelle system.
4. Application in the field of metal corrosion inhibition
Metal corrosion can change the mechanical and physicochemical properties of metal materials, causing 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, with high efficiency and non-toxicity. It can form a dense adsorption film on the metal surface through the strong electrostatic attraction of its double N-headed groups, significantly reducing the corrosion behavior of metals in chemical media. It is currently widely used in petrochemical, transportation, steel and machinery fields.
Mechanism of metal corrosion inhibition by surfactants: Metal surfaces are generally negatively charged. When gemini quaternary ammonium salt surfactants dissolve in water, they dissociate into cations with two charges. The gemini quaternary ammonium salt surfactant ions are adsorbed on the metal surface through electrostatic attraction. The hydrophobic groups can form a dense hydrophobic film on the metal surface, which can effectively isolate water or other anti-corrosion substances from contact with the metal, thereby achieving the purpose of efficient metal corrosion inhibition.
Literature Examples:
Gao Zhinong et al. studied the corrosion protection effect of a series of gemini quaternary ammonium salt surfactants (mnm type) on aluminum in 1mM HCl medium. The results showed that these gemini quaternary ammonium salts had excellent corrosion protection effect on aluminum in acidic media, with the best effect at the critical micelle concentration. Further experiments showed that these gemini quaternary ammonium salts had highly efficient corrosion protection effect on various metals, possessing extremely high application value in 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 showed that the corrosion inhibition rate reached over 95% at a concentration of 35 mg/L. It is a mixed corrosion inhibitor with cathodic inhibition as the main component.
Applications in the textile printing and dyeing industry:
4.1 It can be used as an alkali reduction accelerator for polyester fabrics and a dyeing retarder for cationic dyes.

Gemini quaternary ammonium salts significantly promote alkali reduction treatment of polyester fabrics, resulting in minimal strength loss and improved drape, breathability, and moisture retention. Fibers treated with cationic dyes exhibit lower crystallinity and glass transition temperature, and a looser internal structure, leading to faster adsorption rates. The gemini quaternary ammonium salts added to the dye first penetrate the fiber and bind to sulfonic acid anions, then replace them after the cationic dye enters, thus slowing down the dye adsorption rate and achieving a retarding effect.
Wang Rongxiang et al. applied gemini quaternary ammonium salts (MNM type) as alkali reduction promoters and retarders for polyester fabrics, finding that these salts significantly promoted alkali reduction treatment of polyester fabrics, resulting in excellent fabric performance significantly superior to traditional single-chain quaternary ammonium salts.
4.2 It can be used to improve pinholes in nylon printing .
Nylon is prone to pinholes during acid dye printing, which manifest as localized aggregation on the fabric surface. By adding appropriate gemini quaternary ammonium salts, anionic dyes and gemini quaternary ammonium salts form a spatial network structure on the fabric surface, making the dyes less prone to movement during printing table lifting or drying, thus preventing the formation of textile pinholes. The stable interaction between gemini quaternary ammonium salts and acid dyes is beneficial in reducing the formation of printing pinholes.
Studies have shown that when hydroxyl-containing gemini quaternary ammonium salts are used in combination with other auxiliaries, they can eliminate pinholes generated by dyes during nylon printing.
4.3 Low-salt process in the dyeing of cotton and linen fabrics

The use of large amounts of inorganic salts in cotton dyeing processes poses significant challenges to wastewater treatment, making salt-free/low-salt/alkali-substitute dyeing a research hotspot. Modifying cotton fibers with small amounts of gemini quaternary ammonium salts followed by reactive dyeing can greatly reduce the amount of inorganic salts used, thus lowering costs, reducing environmental pollution, and improving product quality.
Jia Lihua et al. used ester-based gemini quaternary ammonium salts as auxiliaries to dye linen fabrics with reactive dyes, achieving a dyeing rate and fixation rate of over 85% for Reactive Yellow M-3RE. The dyeing performance of linen fabrics treated with this type of gemini quaternary ammonium salt was superior to that of traditional quaternary ammonium salt-CTAB, with both dyeing rate and fixation rate increased by nearly 10%.
5. Applications in Wastewater Treatment:
Compared to traditional quaternary ammonium salts, gemini quaternary ammonium salts have extremely strong adsorption properties and are therefore often used as adsorbents to remove pollutants from liquids. Wastewater treatment using surfactants first requires adsorbing the surfactant onto a medium such as clay or sand, which then adsorbs the pollutants. This is an effective pollution control method.
Literature Examples:
Liu Xuemin’s research group used amide-based gemini quaternary ammonium salts as organic intercalating agents to modify montmorillonite. The results showed that the gemini quaternary ammonium salts successfully intercalated between the layers of montmorillonite. The modified montmorillonite adsorbed 6 times more p-chlorophenol from water than the unmodified montmorillonite, demonstrating good application value in the removal of organic matter from wastewater.
Rosen et al. studied the adsorption of 2-naphthol by traditional quaternary ammonium salts and gemini quaternary ammonium salts. The results showed that montmorillonite with gemini quaternary ammonium salts adsorbed 15 times more 2-naphthol than montmorillonite modified with traditional quaternary ammonium salts, and sand and limestone with gemini quaternary ammonium salts adsorbed 3 times more. Gemini quaternary ammonium salts have the advantages of higher adsorption capacity and efficiency compared to traditional quaternary ammonium salts.
6. Preparation of New Mesoporous Materials
: Mesoporous molecular sieves have large controllable pore sizes and high specific surface areas, and are currently widely used in petroleum catalytic cracking, separation, and nanoscience. Gemini quaternary ammonium salts, due to their structural variability, can form aggregates with various special structures in aqueous solutions, acting as template agents in the preparation of mesoporous materials. Therefore, silicate molecular sieves with different crystal phases and pore sizes can be prepared by controlling the length of the alkyl chain, the length and type of the linking group of the gemini quaternary ammonium salt. Compared with traditional single-chain quaternary ammonium salts, gemini quaternary ammonium salts require significantly less dosage and are less expensive.
Literature examples:
Vander Voort et al. prepared mesoporous materials with different crystal forms by adjusting the length of the linking group in gemini quaternary ammonium salts (mnm type). When n=10, 12, MCM-48 type molecular sieves can be prepared; when n is smaller, MCM-41 is suitable for preparation.
Hu Jun et al. studied the influence of linking groups on silicon-based mesoporous materials using gemini quaternary ammonium salts with flexible and rigid linking groups as template agents, respectively. When the linking group is a flexible methylene group, the results are consistent with those of 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 sphere structure material can be obtained.

7. Other Applications :
The unique molecular structure and excellent surface/interfacial properties of geminal quaternary ammonium salts make them suitable for use as antistatic agents in fabrics. In the paper industry, they can be used as antifungal and bactericidal agents, fiber dispersants, waste paper deinking agents, and antistatic agents.
8. Product Recommendations:
                    Hyperbranched Gemini Gemini Quaternary Ammonium Salts

I. Product Properties
This product is a novel C12-18 asymmetric ethoxygenated Gemini quaternary ammonium salt cationic surfactant, possessing both nonionic and cationic properties. It is environmentally friendly, free of formaldehyde, APEO, NPEO, etc. It exhibits high surface activity, good Ca soap dispersing power, wetting ability, penetrating power, solubilizing ability, antibacterial ability, and lubricating ability.
II. Product Features 
1. Resistant to strong acids (hydrochloric acid/sulfuric acid/acetic acid/citric acid) above 200g/L, and strong alkalis (NaOH) up to 50g/L, suitable for formulating various acidic, neutral, and alkaline water-based degreasing agents, oil-removing powders, and descaling agents.
2. Good compatibility; compatible with some anionic surfactants without precipitation.
3. No cloud point; suitable for use in both normal and high-temperature environments.
4. Wide range of applications: suitable for immersion, ultrasonic, and electrolytic degreasing cleaning methods.
III. Technical Specifications

Appearance	Pale yellow to brownish-yellow slightly cloudy liquid
Solid content, %	≥60
pH (5% aqueous solution)	7±2
Shelf life	1 year

IV. Product Uses
1. High-grade industrial and domestic cleaning agent;
2. Antistatic agent for fibers, plastics, etc.;
3. Pesticide synergist;
4. Oilfield displacement agent, surface tension reducer, and sludge separator.
V. Packaging and Storage
1. This product is packaged in 200kg plastic drums.
2. The packaging drums should be marked with the following: product name, manufacturer’s name, batch number, net weight, production date, and product certificate.
3. This product should be stored in a cool, dark place. During transportation, it should be protected from direct sunlight, rain, and high temperatures. This product is not a hazardous material.