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[Display omitted] Cationic surfactants have a wide range of applications, often associated with their affinity for a range of solid surfaces and their anti-microbial properties. Manipulating their adsorption and self-assembly properties is key to most applications, and this is commonly achieved through surfactant mixtures or manipulating their headgroup or alkyl chain structure. Achieving this through adjustments to their headgroup structure is less common in cationic surfactants than in anionic surfactants. Ethoxylation provides the ability to adjust the hydrophilic / hydrophobic balance, as extensively demonstrated in a range of anionic surfactants. This same approach has been applied here to a range of ethoxylated cationic surfactants in the form of the quaternary ammonium salts, and their tertiary nonionic equivalents before quaternisation. Their adsorption and self-assembly properties are investigated using predominantly the neutron scattering techniques of neutron reflectivity, NR, and small angle neutron scattering, SANS. The trends in the adsorption at the air–water interface and the self-assembly in aqueous solution demonstrate how the hydrophilic / hydrophobic balance can be adjusted by varying the degree of ethoxylation and the alkyl chain length, and illustrate the degree of interdependence of the different structural changes. The variation in the adsorption and the micelle structure shows how the surfactant conformation / packing changes as the degree of ethoxylation and alkyl chain length increases and how the introduction of charge induces further changes. [ABSTRACT FROM AUTHOR]

The development of novel synthetic methods for quaternary ammonium salts is highly demanded since the current synthesis heavily relies on the conventional Menshutkin reaction. Herein, we report photoredox-catalyzed alkylation of α-brominated alkenylammonium salts. Mechanistically, the generation of a highly reactive α-ammoniovinyl radical is the key to our method. This reaction enables the synthesis of various unprecedented α-alkylated alkenylammonium salts. [ABSTRACT FROM AUTHOR]

The paper presents the results of anticorrosion gravimetric studies of the quaternary nitrogen-containing derivatives of 2-allyl-4-isodecylphenol, namely, the quaternary ammonium salts 2-allyl-4-isodecyl-6-diethylaminomethylphenol (I) and 2-allyl-4-isodecyl-6-piperidinomethylphenol (II) on steel St.3 plates in a system consisting of a 3% aqueous NaCl solution and hydrocarbons (kerosene) at a ratio of 9 : 1 (vol/vol). The influence of the temperature and concentration of the compounds on the corrosion rate, metal surface coverage, and protective effect was studied (test time 5 h). Compounds I and II were found to have high inhibitory properties. The thermodynamic parameters of adsorption (ΔG, ΔH, ΔS) were determined, based on which the chemisorption blocking mechanism of steel St.3 surface protection was proposed. The chemisorption process is described by the Langmuir isotherm. [ABSTRACT FROM AUTHOR]

Reaction of a quaternary ammonium salt with GaCl3 in concentrated HCl aqueous solution led to an organic–inorganic hybrid perovskite material [Me3NCMe3][GaCl4] (1), which shows a two-step off–on–off second harmonic generation (SHG) response with a rapid and large temperature interval. [ABSTRACT FROM AUTHOR]

The present study explores the cleaning efficacy of a set of nonionic surfactants (linear ethoxylated alcohol, secondary ethoxylated alcohols with 5, 7, and 9 ethoxy groups, glycoside surfactants, polyglycerol surfactants, and an ethoxylated sorbitan monolaurate) combined with cationic biocides—alkyl quaternary ammonium salts. A simple hard surface cleaning methodology was applied, which was shown to discriminate well between poor and good cleaning formulations. In addition to cleaning efficacy, surface aesthetics such as gloss and haze were evaluated together to assess surface streaking caused by a residual surfactant layer. The haziness determination turned out to be the key feature revealing the complex cleaning performance of multi‐component products. [ABSTRACT FROM AUTHOR]

The double skeleton interpenetrating network fixed the quaternary ammonium salt, and various internal conduction modes cooperated to promote the transport of hydroxide ions. [Display omitted] The alkaline solid-state electrolytes have received widespread attention for their good safety and electrochemical stability. However, they still suffer from low conductivity and poor mechanical properties. Herein, we report the synthesis of double-network featured hydroxide-conductive membranes fabricated by polyvinyl alcohol (PVA) and chitosan (CS) as the double-skeletons. Then, we implanted quaternary ammonium salt guar hydroxypropyltrimonium chloride (GG) as the OH− conductor for high-performance electrochemical devices. By virtue of the unique stripe-like structure shared from the double skeleton with a high degree of compatibility and stronger hydrogen bond interactions, the polyvinyl alcohol/chitosan-guar hydroxypropyltrimonium chloride (PCG) solid-state electrolytes achieved optimal thermal stability (> 300 °C), mechanical property (∼ 34.15 MPa), dimensional stability (at any bending angle), and high ionic conductivity (13 mS cm−1) and ion mobility number (t ion ∼ 0.90) compared with chitosan-guar hydroxypropyltrimonium chloride (CG) and polyvinyl alcohol-guar hydroxypropyltrimonium chloride (PG) electrolyte membrane. As a proof-of-concept application, the "sandwich"-type zinc-air battery (ZAB) assembled using PCG membrane as the electrolyte realized a high open-circuit voltage (1.39 V) and an excellent power density (128 mW cm−2). Notably, in addition to its long-term cycle life (30 h, 2 mA cm−2) and stable discharge plateau (12 h, 5 mA cm−2), it could even enable a flexible ZAB (F-ZAB) to readily power light-emitting diodes (LED) at any bending angle. These merits afford the PCG membrane a promising electrolyte for improving the performance of solid-state batteries. [ABSTRACT FROM AUTHOR]

AbstractIn this paper, the inhibition efficiency and mechanism of a newly synthesized imidazoline-pyridine quaternary amine salt (IPS) as a corrosion inhibitor for carbon steel in 1.00 mol/L HCl at different temperatures were investigated experimentally and theoretically. The inhibitor is confirmed by nuclear magnetic resonance spectroscopy (NMR) and fourier transform infrared spectroscopy (FT-IR). Electrochemical and weight loss indicate that the IPS displays a stable protection performance at different temperatures. Moreover, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS) indicates that the IPS can be stably adsorbed on Q235 steel surface. Molecular dynamics (MD) show that mainly imidazole and pyridine rings of IPS are adsorbed on the surface of Fe. Moreover, radial distribution function (RDF) and the mean-square displacement (MSD) were used to study inhibitor/metal interactions and migration rate of corrosive species, respectively. The results can provide useful guidance for further study on the corrosion inhibition of imidazole-pyridine quaternary amine salts. [ABSTRACT FROM AUTHOR]

Highly complex fused systems are widely present in drug development. The direct electrosynthesis of fused systems through radical domino reactions features higher atom and step economy, using abundantly available starting materials and avoiding exogenous oxidants and reductants, and thus it has been in high demand and recognized as a green, powerful, and versatile synthetic tool but remains challenging because of the instability of the radical species under the electrolysis conditions and the inclusion of a quaternary ammonium salt. Herein, we developed a de novo electrosynthesis of 6-6-5 fused systems with two new rings constructed using a user-friendly undivided cell through decarboxylation and three-step radical addition under exogenous oxidant and quaternary ammonium salt free conditions. Excellent functional group, water and air compatibility was observed with good yields obtained. [ABSTRACT FROM AUTHOR]

The grafting of trialkoxysilanes is the most common method for the surface functionalization of silica gel, and it is usually carried out in the presence of toluene or other solvents such as acetonitrile or acetone. Here, we replaced these solvents with alcohols to afford silica materials containing alkoxy groups linked to the silicon atom. The grafting of N,N-dimethyl-3-amino- or 3-amino-propyltrimethoxysilane was carried out in the presence of several alcohols containing an unsubstituted alkyl chain (C7 and C14), a PEG functionalized chain, or an amino-substituted chain (N,N-dimethylamino, pyridyl). Materials were characterized via solid-state 13C- and 29Si CPMAS NMR and thermogravimetric analysis to prove that alcohols are not "innocent" solvents but take part in the reaction and lead to [RSi(OR1)-(OSi)2] systems where the OR1 group proceeds from the alcohol used in the synthesis. As a proof of concept, we briefly studied the catalytic activity of some of these materials with the aim of showing how different modifications can influence the course of a selected reaction. Finally, a quaternary ammonium salt (QAS)-based silica was prepared containing both an alkyl-QAS and an alkoxy-QAS linked to silicon atoms. This could represent an interesting approach for the development of new antifouling-based materials and, overall, the described strategy could be useful for the preparation of new organosilica materials. [ABSTRACT FROM AUTHOR]

In this study, poly(lactic acid), poly(ethylene glycol), and benzalkonium chloride with different concentrations (3, 5, 7, and 9%wt.) (PLA/PEG/BCL) composite electrospun mats were produced. PLA is a non‐toxic polymer with high biocompatibility and biodegradability. However, it may be fragile due to its structure. Therefore, in this study, PEG was used as a plasticizer to improve the structural properties of PLA and it was aimed at providing antibacterial properties by adding BCL salt. Its use as an antibacterial composite nanomaterial effective against Gram‐positive Staphylococcus aureus (S. aureus) and Gram‐negative Escherichia coli (E. coli) bacterial cultures and as a dermal wound dressing material has been examined in two different areas. The addition of BCL salt reduced the bead formation in PLA/PEG nanofibers and increased the homogeneity of fiber dispersion. 9% BCL‐doped composite nanofiber was obtained as the smoothest and most homogeneous surface. This mat was reported to have the highest ductility. The low Tm of pure BCL salt enabled the Tg temperature of PLA/PEG/BCL composite nanofibers to be observed. It was observed that as the BCL salt ratio increased, the T5 and T10 temperatures of the nanofibers decreased and then increased. BCL‐doped mats exhibited liquid absorption behavior in the range of 497%–708%. PLA/PEG/BCL composite nanofibers showed high toxicity to the L929 fibroblast cell line. So, it has been reported that it cannot be used as a dermal wound dressing. PLA/PEG/BCL composite nanomaterials were reported to have 99.99% antibacterial activity against E. coli and S. aureus. It was suggested that it could be used in antibacterial coating applications by taking into account modern nanocoating technology. Highlights: Poly(lactic acid), poly(ethylene glycol), and benzalkonium chloride (PLA/PEG/BCL) composite electrospun mats were produced.The addition of BCL salt reduced the bead formation in PLA/PEG nanofibers and increased the homogeneity of fiber dispersion.9% BCL‐doped composite nanofiber was obtained as the smoothest and most homogeneous surface.PLA/PEG/BCL composite nanofibers showed high toxicity to the L929 fibroblast cell line.PLA/PEG/BCL composite nanomaterials were reported to have 99.99% antibacterial activity against E. coli and S. aureus. [ABSTRACT FROM AUTHOR]

Four ester cationic Gemini surfactants (EDQ‐n, n represents the carbon number in the raw fatty acid of 12, 14, 16 and 18) were synthesized from fatty acid, N, N‐dimethylethanolamine and 1, 4‐dibromobutane by two‐step reaction of esterification and quaternization. Their surface activities at air/water interface were investigated. The application performance such as water solubility, antistatic property, fabric softness, fabric whiteness, biodegradability, and antibacterial activities were tested and compared with traditional quaternary ammonium salt. The results showed that the γcmc increases with increasing the hydrophobic chain length and EDQ‐12 presented the highest surface activity. The diffusion coefficients calculated from the Ward‐Tordai equation indicates the adsorption process is a mixed‐diffusion kinetic adsorption mechanism. The water solubility of EDQ‐n is higher than dioctadecyl dimethyl ammonium chloride (D1821) and ester quaternary ammonium salt (Esterquats). The fabric softness and whiteness properties of EDQ‐16 and EDQ‐18 are similar to D1821 and Esterquats, which can significantly reduce the cotton fabric softness and have no significant difference in whiteness retention. EDQ‐n demonstrated more readily biodegradation(>90 %) than D1821(0 %) after seven days. In addition, EDQ‐12 and EDQ‐14 show excellent antibacterial activities against Staphylococcus aureus and Escherichia coli in comparison with conventional bacteriostatic agent didecyl dimethyl ammonium chloride (DDAC). [ABSTRACT FROM AUTHOR]

Liposomes have been extensively applied in gene and drug delivery. It is indicated in many studies that cationic lipids possess a certain degree of cytotoxicity, primarily induced by the lipid head group. In this study, we investigated the cytotoxic mechanisms of peptide headgroup lipid (CDO14) and quaternary ammonium salt headgroup lipid (CDA14) on the NCI-H460 and MRC-5 cell lines. Both lipids were synthesized in our laboratory and with high transfection efficiency. The differences in changes of relevant proteins during the process of inducing cell apoptosis were compared at the cellular level between the two lipids. The results showed that both types of liposomes could lead to an increase in intracellular reactive oxygen species, a decrease in ATP content, a decrease in mitochondrial membrane potential, an increase in cytochrome c content, an increase in the BAX/BCL-2 ratio, and an increase in cleaved caspase-3 content. Among these changes, the variations in CDA14 were more significant than those in CDO14. Additionally, the cellular uptake of CDA14 was significantly higher than that of CDO14. These results suggested that the cytotoxicity of quaternary ammonium salt-based lipids was higher than that of peptide-based lipids. The cytotoxicity of cationic lipids is related to their head group structure, and their cytotoxic effect is mainly achieved by activating caspase-dependent endogenous apoptosis. [ABSTRACT FROM AUTHOR]

Using natural deep eutectic solvents (NADESs) as a green reagent is a step toward producing environmentally friendly and sustainable technology. This study screened three natural DESs developed using quaternary ammonium salt and organic acid to analyse their capability to extract nickel ions from contaminated mangrove soil, which are ChCl: Acetic Acid (ChCl-AceA), ChCl: Levulinic Acid (ChCl-LevA), and ChCl: Ethylene Glycol(ChCl-Eg) at molar ratio 1:2. The impact of various operating parameters such as washing agent concentration, pH solution, and contact time on the NADES performance in the dissolution of Ni ions batch experiments were performed. The optimal soil washing conditions for metal removal were 30% and 15% concentration, a 1:5 soil-liquid ratio, and pH 2 of ChCl-LevA and ChCl-AceA, respectively. A single removal washing may remove 70.8% and 70.0% Ni ions from the contaminated soil. The dissolution kinetic of Ni ions extraction onto NADES was explained using the linear kinetic pseudo and intraparticle mass transfer diffusion models. The kinetic validation demonstrates a good fit between the experimental and pseudo-second-order Lagergren data. The model's maximum Ni dissolution capacity, Qe are 51.56 mg g−1 and 52.00 mg g−1 of ChCl-LevA and ChCl-AceA, respectively. The synthesised natural-based DES has the potential to be a cost-effective, efficient, green alternative extractant to conventional solvent extraction of heavy metals. [ABSTRACT FROM AUTHOR]

Ultrafiltration (UF) membranes with excellent dye removal and antibacterial activity are highly desired in dye wastewater treatment, and more importantly environmental protection puts high demands on polymeric membrane materials. In this work, three methacrylate copolymers containing quaternary ammonium salt were synthesized to cast UF membranes. The physicochemical property, structural evolution, dye separation, and antibacterial activity of as‐prepared membranes were systematically investigated. With increased content of the hydrophilic monomer allyl polypropylene glycol (APPG) in the feed, the wettability and positive charge of the resultant membranes were enhanced. Remarkably, the supporting layer of membranes changed from finger‐like pore structure to sponge‐like pore structure by increasing APPG content, and the sponge‐like membranes showed higher retention rates for dyes (99.78% for victoria blue B, 90.49% for methylene blue, and 97.43% for methyl blue) compared with the finger‐like membranes. Besides, the sponge‐like membranes exhibited high rejection for vctoria blue B (>99%) in dye/salt mixture and simultaneously low rejection for salts (<10%), indicating effective selective separation to dye/salt mixture, and also achieved easy regeneration. It was also found that increased hydrophilicity and positive charge endowed membranes with better antibacterial activity. This work will provide an alternative for dye/salt selective separation in dye effluent treatment. [ABSTRACT FROM AUTHOR]

Antibacterial materials with high hydrophobicity have drawbacks such as protein adsorption, bacterial contamination, and biofilm formation, which are responsible for some serious adverse health events. Therefore, antibacterial materials with high hydrophilicity are highly desired. In this paper, UV‐curable antibacterial materials are prepared from silicone−containing Choline chloride (ChCl) functionalized hyperbranched quaternary ammonium salts (QAS) and tri−hydroxylethyl acrylate phosphate (TAEP). The materials show high hydrophilic performance because their water contact angle is as low as 19.3°. The materials also exhibit quite high antibacterial efficiency against S. aureus over 95.6%, fairly high transmittance over 90%, and good mechanical performance with tensile strength as high as 6.5 MPa. It reveals that it is a feasible strategy to develop antibacterial materials with low hydrophobicity from silicone‐modified ChCl‐functionalized hyperbranched QAS. [ABSTRACT FROM AUTHOR]

The application properties such as foam property, electrolyte tolerance, antibacterial activity and antistatic performance of the mixed systems of a novel Gemini quaternary ammonium salt with quadra‐cationic sites (TC‐GS) and sodium fatty alcohol polyoxyethylene ether carboxylate (AE9CNa) at various molar fraction of TC‐GS (αTC‐GS), were investigated systematically. Results show that TC‐GS/AE9CNa mixed systems with different ratios form a homogeneous and transparent solution, which exhibits excellent foam stability and antibacterial activity. The foam volume of the mixed system remains nearly constant from 400 s to 1000 s, and even when TC‐GS is 10 mg/L in the mixed systems, the antibacterial rates against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) for 2 min. are all exceeded 99 %. The mixed systems of TC‐GS/AE9CNa at various αTC‐GS also demonstrate the superior electrolyte tolerance, their maximum tolerance of NaCl, CaCl2 and MgCl2 is severally beyond 270 g/L, 180 g/L and 180 g/L. In addition, both TC‐GS solution and the mixed systems have good antistatic properties, which can reduce the surface resistance of polyester fabric to ≤1010 Ω. [ABSTRACT FROM AUTHOR]

The article presents the results of the study of the oil collecting and oil dispersing properties of the quaternary ammonium salts formed by undecanoic and tetradecanoic acids, which are monobasic carboxylic acids, with triethanolamine (TEA) in distilled, drinking, and sea waters contaminated with Balakhani Oil. The surface activity property of the products of different concentrations of these complexes was calculated using a tensiometer, and the elemental composition was calculated using the calculation method. A comparative study of the element composition of the salts of both acids formed with TEA shows that the mass fraction of carbon in the complex formed by tetradecanoic acid with TEA is higher than in the other complex. Comparison of the surface activity property of the complexes formed by undecane and tetradecanoic acid with TEA shows that the complex compound formed by tetradecanoic acid with TEA shows more surface activity property. Therefore, as the mass fraction of carbon element increases in the complexes formed by undecane and tetradecanoic acid with TEA, the complex compound shows more surface activity properties. [ABSTRACT FROM AUTHOR]

This study focused on developing an advanced bitterness sensor designed to minimize interference from common anions such as nitrate (NO3−) and iodide (I−) by incorporating partially dissociated amine compounds into the sensor membrane. The conventional bitter sensor (C00) uses fully dissociated quaternary ammonium salt tetradecyl ammonium bromide (TDAB), which typically exhibits high responses to these anions, leading to inaccurate bitterness assessments. To address this issue, we explored the use of three partially dissociated amines—oleylamine (OAm), dioctadecylamine (DODA), and tridodecylamine (TDA)—as lipids in the membrane components. We fabricated sensor membranes and tested their ion selectivity, interference resistance to anion, and sensitivity to iso-alpha acids (IAAs), representative bitter compounds in beer. The results showed that the membranes with partially dissociated amines significantly reduced anion interference. Notably, the sensitivity of the TDA membrane to IAAs was 80.4 mV/dec in concentration, exceeding the 68.5 mV/dec of the TDAB membrane. This enhanced sensitivity, coupled with reduced anion interference, reveals a novel property of partially dissociated lipids in taste sensors, distinguishing them from fully dissociated lipids. These findings pave the way for the development of sensors that can accurately assess a bitter taste and have potential applications in the food and beverage industry. [ABSTRACT FROM AUTHOR]

pH-responsive hydrogel antibacterial microspheres were prepared by complex coacervation method and used as drug carriers to load the antibiotic substitute potassium diformate (KDF). The results showed that the three-dimensional network structure of the composite hydrogel was formed among the polysaccharide components, and Zeolite A loaded with KDF was uniformly dispersed in it. The results of drug release behavior and kinetics in vitro showed that the drug release rate was higher and the release mechanism followed the Ritger-Peppas model, which indicated that the antibacterial microspheres had a good pH response. In vitro, the carrier showed broad-spectrum antibacterial activity, good biocompatibility, and degradability. Sodium carboxymethylcellulose and pectin synergistic by hydrogen bonding, potassium dicarboxylate-loaded Zeolite A is filled in a three-dimensional hydrogel network, and chitosan quaternary ammonium salts coat the outer layer. [ABSTRACT FROM AUTHOR]

Quaternary ammonium salts (QASs) have been used as antimicrobial agents, surfactants, and ionic liquids in electrical double-layer capacitors, rechargeable lithium-ion batteries, and dye-sensitized solar cells. It is well known that solvents and reactants strongly affect the Menshutkin reaction. However, QASs are potentially harmful to humans and the environment. To address these issues, we report the effects of solvent polarity on the thermochemistry of two selected Menshutkin reactions, (1) trimethylamine and 1-iodopropane yielded propyltrimethylammonium, and (2) methylacetamide and 1-iodopropane yielded acetylpropylmethylammonium. We systematically constructed possible QAS unique conformers within the first-principles framework in solvents that have three various polarities: toluene, acetonitrile, and water. The polar solvent shifted both reactions toward exergonic and decreased the Gibbs free activation energy. In addition, the polar solvent changed the favorable reaction for the acetylpropylmethylammonium formation only due to an intramolecular hydrogen bond. Therefore, we suggest that selecting high solvent polarity should be considered to address the potential health and environmental effect. [ABSTRACT FROM AUTHOR]

The current study investigates the production of organoclay suitable for use in the base section of a passenger tire with a cap/base tread construction. The process involved the purification and modification of two types of sodium bentonite clay with different mineral characteristics and ion exchange capacities using a single-step process. The modification process of purified bentonite suspensions was performed using a two-tailed long-chain alkyl quaternary ammonium salt surfactant, namely di (hydrogenated tallow alkyl) dimethyl ammonium chloride (AD2HT), and two one-tailed long-chain alkyl quaternary ammonium salt surfactants, namely cetyl-trimethylammonium chloride (CTAC) and octadecylamine chloride (ODA), in relatively low amounts of surfactant (0.95 CEC), along with polyethylene glycol (4% clay) as an auxiliary modifier. X-ray diffraction (XRD) showed that the interlayer spacing of organoclays significantly increases. In addition, the XRD pattern depends on the kind of surfactant and is independent of the type of bentonite clay. The resulting organoclays were added to the tread base section of a passenger tire using the melt masterbatch technique along with a silane coupling agent. An increase in curing maximum torque (8–15%), curing delta torque (6–14%), hardness (2–10%), static modulus 300 (2–18%), and dynamic storage modulus (11–30%) of the rubber composites was observed without significant change of resilience and loss factor of the composite at 2 Phr of organoclay loadings. The organoclays based on the AD2HT modifier exhibited better mechanical properties than those based on the ODA and CTAC surfactants. The dynamic storage modulus of composites increased by about 30% with only 2 Phr of AD2HT-modified bentonites. Furthermore, the performance of the organoclay was found to be independent of the primary particle size, iron content, and ion exchange capacity of the bentonite clay within the studied range. [ABSTRACT FROM AUTHOR]

In order to improve the electrical conductivity of nylon 6 (PA6) and avoid misfires and explosions caused by static charge accumulation, a quaternary ammonium salt polyionic liquid (PIL) antistatic agent was synthesized in this paper. The surface resistance of PA6 was reduced to 108Ω with the addition of 2 wt% antistatic agent, and the mechanical properties and aging resistance of the substrate were improved. Meanwhile, the morphology and crystallinity of PIL/PA6 composites were further characterized by scanning electron microscope (SEM), energy dispersion spectrometer (EDS) and X-ray diffraction (XRD). It is worth noting that the quaternary ammonium salt polyionic liquid antistatic agent synthesized in this paper has the advantages of excellent antistatic effect, durability, low cost, and simple reaction condition, so it has a broad application prospect in the antistatic aspect of PA6. [ABSTRACT FROM AUTHOR]

The increasing emergence of multidrug-resistant (MDR) pathogens due to antibiotic misuse translates into obstinate infections with high morbidity and high-cost hospitalizations. To oppose these MDR superbugs, new antimicrobial options are necessary. Although both quaternary ammonium salts (QASs) and phosphonium salts (QPSs) possess antimicrobial effects, QPSs have been studied to a lesser extent. Recently, we successfully reported the bacteriostatic and cytotoxic effects of a triphenyl phosphonium salt against MDR isolates of the Enterococcus and Staphylococcus genera. Here, aiming at finding new antibacterial devices possibly active toward a broader spectrum of clinically relevant bacteria responsible for severe human infections, we synthesized a water-soluble, sterically hindered quaternary phosphonium salt (BPPB). It encompasses two triphenyl phosphonium groups linked by a C12 alkyl chain, thus embodying the characteristics of molecules known as bola-amphiphiles. BPPB was characterized by ATR-FTIR, NMR, and UV spectroscopy, FIA-MS (ESI), elemental analysis, and potentiometric titrations. Optical and DLS analyses evidenced BPPB tendency to self-forming spherical vesicles of 45 nm (DLS) in dilute solution, tending to form larger aggregates in concentrate solution (DLS and optical microscope), having a positive zeta potential (+18 mV). The antibacterial effects of BPPB were, for the first time, assessed against fifty clinical isolates of both Gram-positive and Gram-negative species. Excellent antibacterial effects were observed for all strains tested, involving all the most concerning species included in ESKAPE bacteria. The lowest MICs were 0.250 µg/mL, while the highest ones (32 µg/mL) were observed for MDR Gram-negative metallo-β-lactamase-producing bacteria and/or species resistant also to colistin, carbapenems, cefiderocol, and therefore intractable with currently available antibiotics. Moreover, when administered to HepG2 human hepatic and Cos-7 monkey kidney cell lines, BPPB showed selectivity indices > 10 for all Gram-positive isolates and for clinically relevant Gram-negative superbugs such as those of E. coli species, thus being very promising for clinical development. [ABSTRACT FROM AUTHOR]

In the paper, five quaternary ammonium salts derived from rosin were synthesized, characterized and their antifungal activities against different molds were studied. Choline quaternary ammonium salt and tetramethylammonium hydroxide were synthesized from dehydroabietic acid and the rosin ethanolamine ester quaternary ammonium salts which are new compounds were synthesized from propylene pimaric acid. Their structures were confirmed by FTIR, 1HNMR, 13CNMR, and high resolution mass spectrometry. The antifungal activities of the synthesized quaternary ammonium salts from rosin acid were tested by Oxford cup method, and their minimum inhibitory concentration was determined. The results show that quaternary ammonium salts derived from rosin acid have inhibitory effects on bamboo slices to some extent. Among them, propylene pimaric acid ethanolamine ester quaternary ammonium salts (A1 and A2) showed obvious antifungal activity in the Oxford cup test. The Oxford cup activity test and anti-mildew effect of quaternary ammonium salts (B1 and B2) synthesized from rosin acid are significant, and there are almost no mould growth on bamboo slices. It can be inferred that A1, A2, B1 and B2 are expected to be used as bamboo mildew inhibitors. Five quaternary ammonium salts derived from rosin were synthesized and characterized; and their antifungal activities against different molds were studied. [ABSTRACT FROM AUTHOR]

The adherence of pathogenic microorganisms to surfaces and their association to form antibiotic-resistant biofilms threatens public health and affects several industrial sectors with significant economic losses. For this reason, the medical, pharmaceutical and materials science communities are exploring more effective anti-fouling approaches. This review focuses on the anti-fouling properties, structure–activity relationships and environmental toxicity of quaternary ammonium salts (QAS) and, as a subclass, ionic liquid compounds. Greener alternatives such as QAS-based antimicrobial polymers with biocide release, non-fouling (i.e., PEG, zwitterions), fouling release (i.e., poly(dimethylsiloxanes), fluorocarbon) and contact killing properties are highlighted. We also report on dual-functional polymers and stimuli-responsive materials. Given the economic and environmental impacts of biofilms in submerged surfaces, we emphasize the importance of less explored QAS-based anti-fouling approaches in the marine industry and in developing efficient membranes for water treatment systems. [ABSTRACT FROM AUTHOR]

Due to their excellent properties, antimicrobial fiber membranes are widely applied in bioprotective materials. This work addresses the preparation of thermoplastic polyurethane (TPU)-based fiber membranes with active antimicrobial properties. 2-hydroxypropyl trimethyl ammonium chloride-terminated hyperbranched polymer (HBP-HTC) was synthesized and used as an antimicrobial agent. The fiber membranes were obtained by electrospinning a mixed solution of HBP-HTC and TPU. Different electrospinning conditions were investigated, such as the spinning voltage and drum rotation speed. The fiber membrane prepared under a 22 kV anode voltage and 100 rpm rotation speed had an average fiber diameter of 1.66 μm with a concentrated diameter distribution. Antibacterial tests showed that when the fiber membrane was loaded with 1500 mg/kg of HBP-HTC, the antibacterial rates of E. coli as well as S. aureus both reached 99.99%, exhibiting excellent proactive antimicrobial performance. Moreover, the protective performance of the fiber membrane was outstanding, with a filtration efficiency of 99.9%, a hydrostatic pressure resistance greater than 16,758 Pa, and a moisture permeability of 2711.0 g⋅(m2⋅d)−1. [ABSTRACT FROM AUTHOR]

A new type of UV-curable pressure-sensitive adhesive containing Si atoms (Si-PSAs) was prepared by a solution-free UV-initiated telomerization process of n-butyl acrylate, acrylic acid, methyl methacrylate, and 4-acrylooxybenzophenone using triethylsilane (TES) as a telogen and an acylphosphine oxide (APO) as a radical photoinitiator. Selected commercial adhesion promoters were tested as additives in the formulation of adhesive compositions, i.e., (i) an organic copolymer with polar groups (carboxyl and hydroxyl); (ii) a hydroxymetal-organic compound; and (iii) a quaternary ammonium salt and (iv) a chlorinated polyolefin. No fillers, crosslinking agents, or photoinitiators were used in the adhesive compositions. NMR techniques confirmed the incorporation of silicon atoms into the polyacrylate structure. The influence of adhesion promoters on the kinetics of the UV-crosslinking process of Si-PSAs was investigated by a photo-DSC technique. The obtained Si-PSAs were characterized by adhesion (to steel, glass, PMMA, and PE), tack, and cohesion at 20 °C. Finally, the wetting angle of Si-PSAs with water was checked and their thermal stability was proved (TGA). Unexpectedly, the quaternary ammonium salt had the most favorable effect on improving the thermal stability of Si-PSAs (302 °C) and adhesion to glass and PMMA. In contrast, Si-PSAs containing the hydroxymetal-organic compound showed excellent adhesion to steel. [ABSTRACT FROM AUTHOR]

Secondary caries is one of the main reasons for dental filling replacement. There is a need to obtain dental restorative material that is able to act against caries-inducing microorganisms. This study explores the antimicrobial properties of cetyltrimethylammonium bromide (CTAB) or dimethyldioctadecylammonium bromide (DODAB)-modified photo-cured experimental dental composites against Escherichia coli, Streptococcus mutans, and Candida albicans. The antimicrobial activity against Escherichia coli, Streptococcus mutans, and Candida albicans was assessed by using an Accuri C6 flow cytofluorimeter, and then analyzed using BD CSampler software (1.0.264). Bacterial/yeast surface colonization was carried out by using an GX71 inverted-optics fluorescence microscope equipped with a DP 73 digital camera. For bactericidal surface analysis of each sample type, simultaneous standardization was performed using a positive control (live cells) and a negative control (dead cells). A positive correlation between the increasing concentration of CTAB or DODAB and the dead cell ratio of Escherichia coli, Streptococcus mutans, and Candida albicans was revealed. In particular, CTAB at a 2.0 wt% concentration exhibits superior efficiency against pathogens (65.0% dead cells of Escherichia coli, 73.9% dead cells of Streptococcus mutans, and 23.9% dead cells of Candida albicans after 60 min). However, Candida albicans is more resistant to used salts than bacteria. A CTAB- or DODAB-modified experimental dental composite exhibits antimicrobial potential against Escherichia coli, Streptococcus mutans, and Candida albicans after 10 and 60 min of incubation, and the antimicrobial efficiency increases with the wt% of QAS in the tested material. [ABSTRACT FROM AUTHOR]

Methane (CH4) dissolved in water is readily consumed by CH4‐oxidizing bacteria, so the possibility of the dissolved CH4 concentration (dCH4) in sampled water changing before analysis is a concern. To determine the accurate in situ dCH4 level, mercury chloride (HgCl2) or sodium azide (NaN3) is traditionally used for sample preservation. However, these preservatives are very toxic and great care must be taken when adding them to samples. Benzalkonium chloride (BAC), a quaternary ammonium salt cationic surfactant, is a readily available disinfectant that is less harmful to the human body than HgCl2, NaN3, and other preservatives. In this study, we investigated the usefulness of BAC in preserving dCH4 in swamp water, which is a critical terrestrial source of CH4. The dCH4 in samples without BAC decreased immediately after sample collection, whereas the dCH4 in the samples with added BAC did not change significantly for at least 15 d. In addition, when BAC was added to 18 water samples with different water chemistries, the dCH4 did not change significantly from immediately after sampling to 1 week after sampling (average difference: 3%). Thus, in the water samples used in this study, BAC effectively preserved dCH4 in the samples for at least 1 week. Further testing of the effect of BAC on the preservation of dCH4 in different types of water samples worldwide will help to establish a more complete, simple, and safe method. [ABSTRACT FROM AUTHOR]

Chitosan was used as the raw material. A quaternization reaction was carried out between 2,3-epoxypropyltrimethylammonium chloride and water-soluble chitosan to prepare quaternary ammonium salt water-soluble chitosan (QWSC), and its corrosion inhibition performance against the corrosion of carbon steel in stone processing wastewater was evaluated. The corrosion inhibition efficiencies of QWSC on carbon steel in stone processing wastewater were investigated through weight loss, as well as electrochemical and surface morphology characterization techniques. The results show that QWSC has superior corrosion inhibition performance for A3 carbon steel. When an amount of 60 mL·L−1 is added, the corrosion inhibition efficiency can reach 59.51%. Electrochemical research has shown that a QWSC inhibitor is a mixed-type corrosion inhibitor. The inhibition mechanisms of the QWSC inhibitor revealed that the positive charge on the surface of carbon steel in stone wastewater was conducive to the adsorption of Cl− in the medium, which produced an excessive negative charge on the metal's surface. At the same time, the quaternary ammonium cation and amino cation formed in QWSC in stone processing wastewater can be physically absorbed on the surface of A3 carbon steel, forming a thin-film inhibitor to prevent metal corrosion. [ABSTRACT FROM AUTHOR]

In this paper, a novel polymeric antistatic agent, TMQ, with excellent antistatic properties, low cost, and good compatibility with polypropylene (PP), was prepared from isopentenyl polyoxyethylene ether (TPEG), maleic anhydride (MAH) and homemade quaternary ammonium salt (QAS). The structure is characterized using FTIR and 1H NMR. How the addition of TMQ and the molar ratio of TPEG, QAS, and MAH affect the antistatic, mechanical, and crystalline properties of PP are investigated. The results show that as the feed ratio of TPEG, MAH and QAS is TPEG:MAH:QAS = 1:8:8, the modified PP displays the best overall performances. Further exploring finds out when TMQ is added at 15 wt%, the surface resistivity of PP reduces to 6.78 × 109 Ω/sq and the volume resistivity of PP reduces to 7.9 × 109 Ω cm−1, the notched impact strength and melt index improve by 357% and 991%, respectively, while the tensile strength decreases by 38.6% compared with that of pure PP. Besides, the crystal study shows after TMQ is added, the crystallinity of PP reduces, the melt peak temperature remains essentially unchanged, and the crystallization peak temperature increases slightly. The material has excellent antistatic resistance to washing and durability, and the changes in relative humidity have little effect on its antistatic properties. [ABSTRACT FROM AUTHOR]

Aliphatic quaternary ammonium salts (QASs) with intrinsic photoluminescence (PL) have drawn increasing attention due to the importance of exploring the mechanism of ionic emissive clusters, whereas it remains challenging to clarify structure–property relationships. Here, the effective modulation of photophysical properties of gemini aliphatic QASs (n‐BTADB) is managed by altering the alkyl chain length. Boosted quantum yields (up to 24.6%), prolonged phosphorescence lifetimes (up to 515.2 ms), and varied PL colors are achieved by manipulating the aggregation states of the compounds. Interlaced herringbone packing patterns and strong ionic interactions facilitate the intersystem crossing process and stabilize the triplets. The confluence of varied hydrophobic interactions and chain flexibility results in the fluctuation of phosphorescence lifetimes as the alkyl chain lengthens. Furthermore, the single‐component white‐light emission is obtained in 12‐HBTADB crystals by introducing electron‐rich hydroxyls. These results shed new light on the structure–property relationships of ionic emissive clusters and the rational design of nonconventional ionic luminophores. [ABSTRACT FROM AUTHOR]

Intensive application of chlorine-based disinfectants driven by the COVID-19 pandemic was suspected to be detrimental to receiving water ecosystems, but with little field evidence. We characterized the occurrences of typical disinfectants and microeukaryotic communities in surface waters associated with three wastewater treatment plants (WWTP)-river systems one year after the lockdown in Wuhan, China. Trihalomethanes (THMs) declined from summer 2020 (0.01-1.82 µg/L) to summer 2021 (0.01-0.95 µg/L), whereas quaternary ammonium salts (QAs) increased from summer 2020 (0.53-6.35 ng/L) to summer 2021 (8.49-191 ng/L). Biodiversity monitoring with environmental DNA (eDNA) revealed significant temporal variation in microeukaryotic community composition. The monitored disinfectants were correlated with some eukaryotic communities as demonstrated by redundancy analysis. For example, QAs were positively related to Cryptophyta relative abundance, but negatively related to Rotifera relative abundance. A microeukaryote-based multimetric index indicated ecological impairment near the Han River WWTP outlet in 2020. Our findings indicate the influence of heavily used disinfectants on river microeukaryotic communities, and the usefulness of assessing mid-term ecological risks from disinfectants in the post COVID-19 era. [ABSTRACT FROM AUTHOR]

In view of the problem of poor flowability in the production and transportation of high-wax crude oil and high-viscosity crude oil, crude oil flow improvers are commonly used to reduce their viscosity and pour point. Although polymer-based crude oil flow improvers are highly effective in improving crude oil flowability, there are still problems such as high cost and the need for a large amount of solvent dilution when used. In this work, highly dispersed organic modified nano-montmorillonite was prepared by using Na-based montmorillonite and quaternary ammonium salts, and the influencing factors on the viscosity of the crude oil were investigated. The most effective modified nano-montmorillonite (B@MMT) can reduce the viscosity by 96.7% (21 °C) and depress the pour point by 15 °C. Furthermore, it has shown a high improvement in flowability in the other four different sources of crude oil, with viscosity reduction rates of 52.2, 93.4, 79.1 and 67.4%, respectively. B@MMT was characterized by FTIR, SEM, zeta potential and contact angle. Based on DSC and wax crystal structure analysis, the mechanism of the influence of B@MMT on crude oil viscosity and pour point was explored. Finally, the cost of B@MMT was estimated, and the result shows that, compared with the crude oil flow improver in use, B@MMT has considerable commercial competitive advantages. [ABSTRACT FROM AUTHOR]

For addressing the issue of limited durable antibacterial cotton fabric, this study developed and synthesized quaternary ammonium salt antimicrobial agents. The chemical structure was analyzed by FTIR and 1H NMR. The cotton fabric was subjected to surface modification techniques, such as pad-dry-cure, following the careful selection of appropriate quaternary ammonium salt. The chemical state and surface morphology were evaluated through XPS and SEM. Furthermore, the cotton fabric underwent comprehensive assessments, which included antibacterial testing, laundering cycle testing, evaluation of mechanical properties, and analysis of comfort performance. The results demonstrated that the treated cotton fabric achieved a high bacteriostatic and fungistatic rate of 99.99%, 87.5%, and 99.99% against S. aureus, E. coli, and C. albicans respectively even after 50 laundering cycles, while maintaining exceptional antibacterial effectiveness and laundering durability due to the formation of covalent bonds with the cotton fabric. The treated cotton fabric met AAA grade standards for antibacterial rate without causing any significant decline in mechanical properties. Furthermore, enhancements in hydrophilicity, softness, and wrinkle resistance were observed. [ABSTRACT FROM AUTHOR]

Traditional magnesite desilication flotation collectors struggle to efficiently remove quartz from low-grade magnesite, prompting the exploration of new, highly selective flotation collectors. Addressing this need has become a focal point in mineral processing research. This study introduced heptadecylamine ethylimidazoline quaternary ammonium salt (ODD) as a quartz flotation collector for separating quartz from magnesite. Flotation experiments involving single minerals and artificially mixed minerals demonstrated that magnesite and quartz could be effectively separated under specific conditions: an ODD concentration of 40mg/L and pH=7.0. Zeta potential assessments revealed that the adsorption of ODD increased the potential of quartz by 4.4 times compared to magnesite. Furthermore, contact angle measurements illustrated that ODD selectively increased the hydrophobicity of the quartz surface while not affecting the contact angle of magnesite. X-ray photoelectron spectroscopy (XPS) analysis indicated that ODD's selective adsorption at the quartz surface through interaction with the O sites on quartz rather than magnesite. Drawing from these findings, a flotation separation model from magnesite and quartz under the influence of ODD was formulated. [ABSTRACT FROM AUTHOR]

Newly synthesized gemini quaternary ammonium salts (QAS) with different counterions (bromide, hydrogen chloride, methylcarbonate, acetate, lactate), chain lengths (C12, C14, C16) and methylene linker (3xCH2) were tested. Dihydrochlorides and dibromides with 12 carbon atoms in hydrophobic chains were characterized by the highest biological activity against planktonic forms of yeast and yeast-like fungi. The tested gemini surfactants also inhibited the production of filaments by C. albicans. Moreover, they reduced the adhesion of C. albicans cells to the surfaces of stainless steel, silicone and glass, and slightly to polystyrene. In particular, the gemini compounds with 16-carbon alkyl chains were most effective against biofilms. It was also found that the tested surfactants were not cytotoxic to yeast cells. Moreover, dimethylcarbonate (2xC12MeCO3G3) did not cause hemolysis of sheep erythrocytes. Dihydrochlorides, dilactate and diacetate showed no mutagenic potential. [ABSTRACT FROM AUTHOR]

Aluminum‐air battery (AAB) with alkaline‐based aqueous electrolyte have attracted intensive research interests due to high‐capacity density, low cost, and high safety. However, severe hydrogen evolution reaction (HER) of Al anode in alkaline electrolyte extremely restricts its large‐scale application. In this work, ZnO with a group of quaternary ammonium salts (QAS, denoted as C1, C2, C4, C6, and C8 depending on the length of non‐polar group) are introduced into electrolytes to inhibit HER. It is revealing that capacity density initially increases with C1, C2, or C4, up to 2564 mAh gAl−1 with anodic utilization rate of 86.0%, and then follows by a decline (C6 and C8). The addition of QAS creates "physical‐hydrophobic interface" by non‐polar group owing to its electrophilic property and constructs "chemical‐hydrophobic interface" with polar group by reducing water activity. QAS also promotes the uniform growth of Zn‐based film, as a barrier against H2O. Thus, HER is effectively inhibited to improve the capacity density. With further increasing non‐polar group length (C6 or C8), the bonding status of the film deteriorates with enhanced H2O activity, leading to the recurrence of HER. This work explores the effect of non‐polar groups on inhibiting HER and opens the door to stable anodes for alkaline‐based batteries. [ABSTRACT FROM AUTHOR]

Gemini-type imidazoline quaternary ammonium salt is a new type of environmentally friendly corrosion inhibitor has been widely used in engineering materials. However, most of them are hazardous/toxic compounds derived from petroleum-based products, which did harm to environment. In this work, an environmentally friendly Gemini-shaped imidazoline quaternary ammonium salt corrosion inhibitor (G211) was synthesized using cheap fatty acid recycled from dimer acid industry as feedstock. The corrosion inhibition effects of G211 on Q235 steel in 1 M HCl solution were investigated through weight loss experiments, potential polarization curves, and alternating current impedance spectroscopy experiments. The results show that the inhibition rate of G211 as a mixed-type inhibitor is up to 94.4% and the concentration drop as low as 500 ppm at 25 ℃. The adsorption of G211 on Q235 surface follows Langmuir adsorption isothermal curve. The chemical composition of the Q235 steel surface was analyzed through scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Furthermore, the possible corrosion inhibition mechanism of G211 on the surface of Q235 steel is proposed. This article not only presents an outstanding solution for safeguarding Q235 steel against corrosion but also introduces a feasible method for high-value utilization of monomer acid (MA). [ABSTRACT FROM AUTHOR]

Amidation of lactobionic acid with N,N-dimethylaminopropyltriamine was conducted to obtain N-(3′-dimethylaminopropyl)-lactamido-3-aminopropane (DDLPD), which was quaternized with bromoalkanes of different carbon chain lengths to synthesize double-stranded lactosylamide quaternary ammonium salt N-[N′[3-(lactosylamide)]propyl-N′-alkyl] propyl-N,N-dimethyl-N-alkylammonium bromide (CnDDLPB, n = 8, 10, 12, 14, 16). The surface activity and the adsorption and aggregation behaviors of the surfactants were investigated via equilibrium surface tension, dynamic light scattering, and cryo-electron microscopy measurements in an aqueous solution. The application properties of the products in terms of wettability, emulsification, foam properties, antistatic, salt resistance, and bacteriostatic properties were tested. CnDDLPB exhibited a low equilibrium surface tension of 27.82 mN/m. With an increase in the carbon chain length, the critical micellar concentration of CnDDLPBD decreased. Cryo-electron microscopy revealed that all products except C8DDLPB formed stable monolayer, multi-layer, and multi-compartmental vesicle structures in an aqueous solution. C14DDLPB has the best emulsification performance on soybean oil, with a time of 16.6 min; C14DDLPB has good wetting and spreading properties on polytetrafluoroethylene (PTFE) when the length of carbon chain is from 8 to 14, and the contact angle can be lowered to 33°~40°; CnDDLPB has low foam, which is typical of low-foaming products; C8DDLPB and C10DDLPB both show good antistatic properties. C8DDLPB and C14DDLPB have good salt resistance, and C12DDLPB has the best antimicrobial property, with the inhibition rate of 99.29% and 95.28% for E. coli and Gluconococcus aureus, respectively, at a concentration of 350 ppm. [ABSTRACT FROM AUTHOR]

Alkylation reactions are pivotal in organic chemistry, with wide‐ranging utilization across various fields of applied synthetic chemistry. However, conventional reagents employed in alkylations often pose substantial health and exposure risks. Quaternary ammonium salts (QAS) present a promising alternative for these transformations offering significantly reduced hazards as they are non‐cancerogenic, non‐mutagenic, non‐flammable, and non‐corrosive. Despite their potential, their use in direct organic transformations remains relatively unexplored. This review outlines strategies for utilizing QAS as alternative reagents in alkylation reactions, providing researchers with safer approaches to chemical synthesis. [ABSTRACT FROM AUTHOR]

Luminescent materials with multiple emission centers are attracting more and more attentions due to their potential applications in multicolor displays, polychromatic imaging, information encryption, and ratiometric chemical sensing. Organic molecules with phosphorescence behavior at room temperature (RTP) provide idea candidate for constructing luminescent materials with multiple emission centers, which show great potentials for application in ratiometric chemical sensing owing to its long‐lived emission and high signal‐to‐noise ratio. However, developing RTP materials with multiple emission centers and their application in aqueous solutions remains a huge challenge. Herein, two chromophore isomers (p‐N‐DPC·(PF6)2 and m‐N‐DPC·(PF6)2) based on carbazole and naphthalene units are prepared by using pyridine quaternary ammonium salt as link to improve their solubility in water and form electron deficient centers to facilitate charge transfer (CT). p‐N‐DPC·(PF6)2 displayed multiple emissions behavior, including monomer fluorescence, dimer fluorescence, monomer phosphorescence, dimer phosphorescence, and CT phosphorescence. Especially, p‐N‐DPC·(PF6)2 exhibits monomer fluorescence, dimer fluorescence, and CT phosphorescence in an aqueous solution, which is successfully applied as self‐calibrated dual ratio luminescent sensor for phosphate detection. This study not only provides a strategy to construct luminophore with multiple emissions but also develops a fluorescence/ phosphorescence dual ratio luminescent sensor in an aqueous solution. [ABSTRACT FROM AUTHOR]

Myristyl-γ-picolinium chloride (MGPC) is an alkyl pyridine quaternary ammonium salt and a popular preservative in injectables such as Depo-Medrol (Methylprednisolone acetate). Herein we describe a successful high-p,T,c chemical intensification of MGPC synthesis from neat myristyl chloride and γ-picoline in continuous flow. The process is atom economical, scalable with low reactor footprint and under optimized conditions, consistently affords MGPC in 45 min (instead of 8–12 h reported in literature for a conventional batch process) with excellent yield (> 90%) and purity (> 99%). [ABSTRACT FROM AUTHOR]

The review considers the mechanism of intramolecular cyclization (intramolecular Diels–Alder reaction) of quaternary ammonium salts simultaneously containing β,γ-unsaturated and various enyne fragments. [ABSTRACT FROM AUTHOR]

Under-deposit corrosion is widely present in the pipelines of oil and gas production, causing significant corrosion damage. In this paper, a novel electrochemical cathodic-polarization method was carried out to accelerate the formation of CaCO3 scale on a X65 steel surface in a simulated solution containing scaling ions. Subsequently, pre-scaled X65 steel was placed in a high temperature and pressure autoclave to conduct corrosion weight-loss experiments and in situ electrochemical measurements. The study mainly compared the corrosion inhibition behavior of four quaternary ammonium salt corrosion inhibitors, pyridinium quaternary salt (BPC), quinolinium quaternary salt (BQC), 8-hydroxyquinolinium quaternary salt (BHQ) and pyridinium (1-chloromethyl naphthalene) quaternary salt (1-CPN), in a simulated oilfield scale under corrosive conditions. The results of the weight-loss experiments demonstrated that the inhibition efficiencies of the corrosion inhibitors from high to low were as follows: 1-CPN < BHQ < BQC < BPC. The in situ electrochemical measurements showed that the immersion time and type of corrosion inhibitor had a pronounced influence on the corrosion and corrosion inhibition behavior of X65 steel with CaCO3 coating. It was also proved using both EIS and PC that 1-CPN shows the best inhibition performance in all. Lastly, the inhibition mechanism of corrosion inhibitors at under-deposit conditions was analyzed via a surface morphology observation of SEM. [ABSTRACT FROM AUTHOR]

The fibers from four wheat varieties (FT, XW 26, XW 45, and KW 1701) were selected and chemically modified with NaOH, epichlorohydrin, and dimethylamine to improve the adsorption capacity for anionic dye. The structure of the fibers with or without modification was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectrometry. The modified products were studied from the aspects of adsorption capacities, adsorption kinetics, and thermodynamics to provide a reference for the utilization of wheat bran. By SEM, more porous and irregular structures were found on the modified fibers. The XRD results showed that the crystals from the original fibers were destroyed in the modification process. The changes in fibers' infrared spectra before and after modification suggested that quaternary ammonium salts were probably formed in the modification process. The maximum adsorption capacity of wheat bran fibers for Congo red within 120 min was 20 mg/g for the unmodified fiber (XW 26) and 93.46 mg/g for the modified one (XW 45). The adsorption kinetics of Congo red by modified wheat bran fiber was in accord with the pseudo-second-order kinetic model at 40 °C, 50 °C, and 60 °C, indicating that the adsorption process might be mainly dominated by chemisorption. The adsorption was more consistent with the Langmuir isothermal adsorption model, implying that this process was monolayer adsorption. The thermodynamic parameters suggested that the adsorption occurred spontaneously, and the temperature increase was favorable to the adsorption. As mentioned above, this study proved that the wheat bran fiber could possess good adsorption capacities for anion dye after chemical modification. [ABSTRACT FROM AUTHOR]

Double epoxy group double quaternary ammonium salts (DEpDQAS) were synthesized by epichlorohydrin (ECH) reacting with N,N,N'N'-tetramethylethylenediamine (TMEDA) and N,N,N'N'-tetramethyl-1,6-hexanediamine (TMHDA), respectively. The results of orthogonal experiments showed that temperature and time were the key factors influencing on epoxy value and quaternarization ratio respectively. The optimal condition for higher epoxy value was the reaction temperature at 15 °C and methanol as solvent. The reaction kinetic process was determined by conductivity, which showed that the reaction had a short induction period and appeared discontinuity in progress that the reaction rate of the first stage was almost constant, while the reaction rate of the second stage decreased gradually. The product was characterized by infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). The results of surface tension testing showed that DEpDQAS-6 with longer spacer chain had better surface activity and lowered the solution surface tension to 26 mN·m−1 at 25 °C and CMC 0.27 mol·L−1. The thermodynamic parameters of micellization were obtained basing on charged pseudo-phase model. The studies of cytotoxicity in vitro and antibacterial activity showed that DEpDQAS was biocompatible and its antibacterial activity was more effective against Escherichia coli than against Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Esterquats constitute a unique group of quaternary ammonium salts (QASs) that contain an ester bond in the structure of the cation. Despite the numerous advantages of this class of compounds, only two mini-reviews discuss the subject of esterquats: the first one (2007) briefly summarizes their types, synthesis, and structural elements required for a beneficial environmental profile and only briefly covers their applications whereas the second one only reviews the stability of selected betaine-type esterquats in aqueous solutions. The rationale for writing this review is to critically reevaluate the relevant literature and provide others with a "state-of-the-art" snapshot of choline-type esterquats and betaine-type esterquats. Hence, the first part of this survey thoroughly summarizes the most important scientific reports demonstrating effective synthesis routes leading to the formation of both types of esterquats. In the second section, the susceptibility of esterquats to hydrolysis is explained, and the influence of various factors, such as the pH, the degree of salinity, or the temperature of the solution, was subjected to thorough analysis that includes quantitative components. The next two sections refer to various aspects associated with the ecotoxicity of esterquats. Consequently, their biodegradation and toxic effects on microorganisms are extensively analyzed as crucial factors that can affect their commercialization. Then, the reported applications of esterquats are briefly discussed, including the functionalization of macromolecules, such as cotton fabric as well as their successful utilization on a commercial scale. The last section demonstrates the most essential conclusions and reported drawbacks that allow us to elucidate future recommendations regarding the development of these promising chemicals. [ABSTRACT FROM AUTHOR]

Two allyldimethylalkyl quaternary ammonium salt (AQAS) monomers, N,N-dimethylallylphenylpropylammonium bromide (AQAS1) and N,N-dimethylallylnonylammonium bromide (AQAS2), were synthesized and used to prepare modified polyacrylamide materials. Two new drag reducers were synthesized from acrylamide (AM), sodium acrylate (NaAA) and a cationic modified monomer (AQAS1 or AQAS2) via aqueous solution polymerization, and the copolymers were named P(AM/NaAA/AQAS1) and P(AM/NaAA/AQAS2), respectively. The structures of the drag reduction agents were confirmed by IR and 1H NMR spectroscopies. The molecular weight (Mw) of P(AM/NaAA/AQAS1) was 1.79 × 106 g/mol. When the copolymer concentration was 1000 mg/L and the flow rate was 45 L/min, in fresh water the highest drag reduction rate was 75.8%, in 10,000 mg/L NaCl solution the drag reduction rate decreased to 72.9%. The molecular weight of P(AM/NaAA/AQAS2) was 3.17 × 106 g/mol. When the copolymer concentration was 500 mg/L and the flow rate was 45 L/min, the drag reduction rate reached 75.2%, and in 10,000 mg/L NaCl solution the drag reduction rate was 73.3%, decreased by approximately 1.9%. The drag reduction rate for partially hydrolyzed polyacrylamide (HPAM) was also investigated, and the results showed that the drag reduction rates for 500 and 1000 mg/L HPAM solutions were merely 43.2% and 49.0% in brine, respectively. Compared with HPAM, both of the above copolymers presented better drag reduction capacities. © 2024 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. [ABSTRACT FROM AUTHOR]

The Lycoris radiata (L' Herit.) Herb. is a perennial bulbous plant characterized by its high ornamental and medicinal value, exhibiting a unique growth rhythm where the flower and leaf do not coexist and a period of summer dormancy. However, its metabolic response to various developmental stages remains unclear. To address this gap, we conducted a non-targeted metabolomic analysis spanning six developmental stages of L. radiata. The results showed that most differentially accumulated metabolites (DAMs) demonstrated enrichment predominantly in carbohydrate and amino acid metabolism pathways, with the former being more active during vegetative growth and the latter during reproductive stages. The proportion of DAMs categorized under "quaternary ammonium salts", "tricarboxylic acids and derivatives", "fatty acids and conjugates", and "pyrimidine nucleotide sugars" was notably higher in comparisons between the flowering and dormancy stages than in other comparative groups. Furthermore, DAMs involved in the KEGG pathways of C5-branched dibasic acid metabolism and lysine biosynthesis were uniquely identified during the transition from Dormancy to Flowering. The proportion of DAMs associated with "linoleic acids and derivatives" and "pyridines and pyridine derivatives" was notably higher in the leafing out versus flowering comparison than in other comparative groups. Furthermore, the glycolysis/gluconeogenesis pathway was uniquely enriched by DAMs during this phase. This study provided an in-depth view of metabolite changes in L. radiata over its annual growth cycle, enriching our understanding of the regulatory mechanisms governing its development, dormancy, and flowering. [ABSTRACT FROM AUTHOR]