Structure Of Quaternary Ammonium Salts Research Articles

Preparation, and antibacterial activity of chitosan derivative containing double quaternary ammonium salt and hydantoin structures

Chitosan quaternary ammonium salt antibacterial agents with a single structure have the drawbacks of slow bactericidal speed and poor bactericidal effect, which cannot meet the practical usage requirements. To address the problem, in this study, we designed and synthesized a novel chitosan derivative containing double quaternary ammonium salt and chloride hydantoin structures (QCS-CA-DEADH-Cl) by using chitosan, 5,5-dimethyl hydantoin, methyl iodide, and 2-Dimethylaminoethyl chloride hydrochloride as the main raw materials, and then used as antibacterial agent. The structure of QCS-CA-DEADH-Cl was characterized by Fourier transform infrared spectra, X-ray photoelectron spectroscopy, Thermogravimetric, and Scanning electron microscopy. The antibacterial activity of QCS-CA-DEADH-Cl, and the renewability and stability of N-Cl structure in QCS-CA-DEADH-Cl were explored. The results indicated that the N-Cl structure of QCS-CA-DEADH-Cl has strong renewability and storage stability. Moreover, the synergistic effect of quaternary ammonium salt structure and N-Cl structure endowed QCS-CA-DEADH-Cl with excellent antibacterial activity. This work does not only provide a new perspective for the preparation of novel chitosan antibacterial agents but also contributes to expanding the comprehensive utilization of biomass resources.

Regulating the hydroxyl groups reactivity of cellulose by grafting the quaternary ammonium group to achieve a salt-free and low alkali dyeing process for reactive dye

In this work, a salt-free and low alkali dyeing process was developed through cationic modification of cotton fabric with a series of quaternary ammonium salts (QAS). The dyeing performance indicated that the cationic cotton fabric treated with 3-chloro-2-hydroxypropyldimethyloctane ammonium chloride (CT-8) achieved better K/S value (8.87) and dye fixation (90.47 %) compared to the conventional dyeing process. Notably, the CT-8 treated fabric performed exceptionally under salt-free conditions and with a Na2CO3 concentration of 5 g/L. The rationale behind the adoption of a salt-free and low-alkali dyeing process was attributed to the positive charge of quaternary ammonium groups, which had an augmenting impact on the hydroxyl reaction activity of cotton fabrics. The condensed Fukui function, atomic charge, and HOMO orbital calculations showed that the QAS structure could regulate the hydroxyl reactivity of cationic cotton fabric. Our salt-free and low alkali dyeing process not only achieved the aim of reducing chemical consumption and emissions, but also contributed to better understand the effect of hydroxyl reactivity of cationic cotton on the fixation reaction with reactive dye, and provided a new direction to achieve the require of sustainable development and clean production for a variety of industrial crops and products.

Quaternized hollow TiO2-enhanced the dye adsorption capacity and photogenerated carrier separation for efficient reactive dye removal

Currently, titanium dioxide (TiO2) has been demonstrated as a significant photocatalyst for the efficient removal of reactive dyes in dyeing effluents. However, due to the easy recombination of photogenerated carriers and electrostatic repulsion with reactive dye, single TiO2 cannot achieve satisfactory removal efficiency to reactive dye which is commonly used in cellulose fibers dyeing. Therefore, we prepared hollow titanium dioxide (H-TiO2) by alkaline treatment etching method and introduced quaternary ammonium groups on the surface of H-TiO2 photocatalyst (QAS-H-TiO2) by nucleophilic addition reaction. Improving the adsorption capabilities of C. I. reactive red 2 (RR2) and simultaneously separating the photogenerated carriers via the nitrogen cation of the quaternary ammonium groups facilitated the enhancement of its RR2 removal. The experimental results indicated that the utilization of QAS-H-TiO2 substantially bolstered the removal efficiency of RR2. The impact of molecular structure of quaternary ammonium salts on the adsorption ability of RR2, and the mechanism of regulation for photogenerated carriers, were investigated. It was found that the grafting of the quaternary ammonium group enabled mass and electron transfer channels, resulting in faster adsorption of dyes and separation of photogenerated carriers. This study presents a novel approach for preparing efficient QAS-H-TiO2 for high-performance organic dye removal.

Design and characterization of high performance fluorescent probe for neutral red based on fluorescein monoaldol-3-acetyl coumarin

Based on the fluorescence resonance energy transfer (FRET) principle, a yellow-green light fluorescent probe was designed and synthesized for the detection of neutral red using fluorescein monoaldehyde-3-acetylcoumarin as the fluorophore. The fluorescein moiety in the probe structure is readily interchangeable and heterogeneous in the form of an anion, and the neutral red is a quaternary ammonium salt structure with N. Therefore, the two are bound together in the form of ionic bonds through the mutual attraction of anions and cations. At the same time, FRET occurs, resulting in the absorption of the fluorescence emitted by the probe by the neutral red molecule, leading to a significant quenching of its fluorescence. The probe has a high selectivity for neutral red with a linear range of 0–30 μM and a detection limit of 8. 68 μM. Furthermore, the fluorescent probe has been successfully applied to the detection of neutral red content in real water samples with a recovery of 101 %-115 %. The probe has promising potential in the quantitative detection of neutral red.

A Salt-Resistant Sodium Carboxymethyl Cellulose Modified by the Heterogeneous Process of Oleate Amide Quaternary Ammonium Salt.

In this study, hydrophobic quaternary ammonium intermediate was synthesized by epichlorohydrin (ECH) and oleamide propyl dimethyl tertiary amine (PKO). Sodium carboxymethylcellulose (CMC) was chemically modified by introducing a large number of hydrophobic quaternary ammonium branched chains to improve CMC's salt resistance, thickening ability, and solubility. The quaternary ammonium salt structure can partially offset the compression double-layer effect of linear polymers in a low-price salt ion solution, which makes CMC more stretchable and helps it obtain a higher viscosity and greater drag-reduction performance. The experiment was mainly divided into three parts: Firstly, we performed an epichlorohydrin and oleic acid PKO reaction, generating an oleic acid chain quaternary ammonium chlorine atom intermediate. Secondly, the etherification reaction between intermediate -Cl and -OH groups of CMC was completed. Finally, the modified CMC was characterized by IR, SEM, and XPS, and the viscosity and the drag-reduction rate were evaluated. After CMC and the intermediate were reacted at a mass ratio of 9:1.8 at 80 °C for 5 h, the new CMC with enhanced thickening ability, salt resistance, and drag-reduction performance was obtained. We found that the apparent viscosity increased by 11%, the drag reduction rate increased by 3% on average, and the dissolution rate was also significantly accelerated, which was ascribed to the introduction of quaternary ammonium cation. Moreover, the oleic acid amide chain increased the repulsive force of the CMC chain to low-priced metal cations in solution and intermolecular repulsive force, which is beneficial to increase the viscosity, salt resistance, and drag-reduction performance.

The rapid SERS detection of succinylcholine chloride in human plasma is based on the high affinity between quaternary ammonium salt structures

Succinylcholine chloride (SCC) is a common poison that threatens human life. At present, there is a lack of research on its on-site rapid detection methods. In this work, the use of gold nanorods as an enhanced substrate based on the high affinity between the quaternary ammonium salt structure can achieve rapid SERS detection of SCC in plasma. The long alkane chain structure of cetyltrimethylammonium bromide (CTAB) and the quaternary ammonium salt structure of SCC have a high molecular affinity, so that the target molecule can show a strong and obvious characteristic signal of SERS. Combined with a simple pretreatment method, acetonitrile is used as a protein precipitation agent to effectively remove matrix interference. The constructed SERS substrate can achieve the sensitive detection of 2 × 10-8 M level of SCC in plasma samples and has high detection reproducibility. The entire pre-processing and testing process can be completed within 7 min, which can be used as an important technical basis for the preliminary identification of on-site SCC-related drug cases. The research results provide an effective solution for the establishment of SCC analysis strategies in complex matrices, and can provide new ideas for solving the problems of difficult identification of common poisons in the field and the lack of rapid detection methods on site.

Preparation and Properties of a Kind of Hydrophilic Polyimide Film with Quaternary Ammonium Salt Structure

We synthesized a polyamide acid by copolycondensation reaction using diphenyl ether tetraacid dianhydride (ODPA) as the dianhydride monomer, diaminodiphenyl ether (ODA) and N-methyl-2,2-diaminodiethylamine (diethylamine) as the diamine monomer. Then the polymer with side-linked branch sulfonate structure was synthesized, and the structure of quaternary ammonium salt was added to the polyamide acid. A hydrophilic PI film was prepared by coating and thermal imidization process. The main influence factors in the formation process of hydrophilic PI film were discussed, then its hydrophilic properties and thermal properties were tested. The results show that diethylamine can react with lactone in the PI molecular chain in the DMAc system. The introduction of quaternary ammonium salt significantly improves the hydrophilic properties of the polyimide film surface,the water contact angle of the film dried at 130°C is 58.065°. Above 140°C, breakage and decomposition of the -N+SO3 − structure bond will occur, and the hydrophilic property will decrease.

Влияние активации поверхности волластонита четвертичными аммониевыми солями на релаксационные свойства модифицированных им ПВХ-композиций

It is promising to use wollastonite as a modifier of plasticized polyvinyl chloride compositions. The main advantages of wollastonite are white colour and needle-shaped particles. To improve the compatibility of this filler with a polymer matrix, it is effective to activate the surface of this mineral by quaternary ammonium salts (QAS). Valuable information on molecular motion in modified compositions can be obtained by studying the relaxation processes using dynamic mechanical analysis. In the temperature dependences of the mechanical loss tangent of the PVC compositions in the region of transition from the glassy to highly elastic state, two maxima were observed. It has been established that for compositions modified with both natural and surface treated wollastonite, regardless of the chemical structure of QAS used to activate the polymer. This is probably due to the formation of a boundary layer in which molecular mobility is inhibited because of the interaction of the polymer with the filler. Thawing of segmental mobility in this boundary layer occurs at the higher temperatures than in the PVC matrix. The surface treatment of wollastonite by QAS somewhat shifts the described relaxation transitions to higher temperatures due to an increase in the efficiency of interaction of the components at the interface. The magnitude of the change in the temperature of the segmental mobility, both in the polymer matrix and in the boundary layer, increases with an increase in the degree of activity of the filler surface.

Evaluation of clay-ionene nanocomposite carriers for controlled drug delivery: Synthesis, in vitro drug release, and kinetics

Abstract To evaluate the impact of the different structure of quaternary ammonium salts (ionenes) as drug carrier of their corresponding organoclays, new nanocomposite clay-ionene (CI) drug carriers were prepared from montmorillonite (Mt) and polyquaternary ammonium salts (polyionene) and a simple bisquaternary ammonium salt. The CI drug systems were obtained by ion exchange of the sodium Mt (Na + Mt) with at least two-fold excess polyquaternary and bisquaternary ammonium salt compounds by ion exchange between sodium cations of the Na + Mt and the ammonium ions in the polyionene to produce CI systems with free quaternary ammonium halide side chains. Simple di-quaternary ammonium salts were also used to modify Mt. The structures of the prepared CI systems were characterized using Fourier transform-infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). As a model drug, sodium diclofenac (DS) was immobilized onto the CI through the remaining halide ions to provide the CI-diclofenac system (DFS). The release behavior of diclofenac from the different nanocomposites was studied at different pH values. The release behavior of the DFS showed that polyionene systems were slower than the simple bi-quaternary ammonium salts systems were. The kinetics of the release process were described using different models to explain the drug release mechanism.

Effect of organic modifier type of montmorillonite on the poly (butyl acrylate-co-methyl methacrylate)/montmorillonite nanocomposite

Nanocomposites based on poly(BA-co-MMA) and organo-montmorillonite (OMt) were synthesized by semi batch emulsion polymerization. OMt was used directly after the organic modification of sodium montmorillonite (Mt). By this way, dispersion of OMt in emulsion polymerization was improved. OMts were prepared by organic modification of Resadiye Mt (bentonite) with five different quaternary ammonium salts (QAS) to observe the effect of structural difference on the poly(butyl acrylate-co-methyl methacrylate) nanocomposites. The affinity of OMts towards organic liquids was observed via swelling test in toluene and butyl acrylate (BA)-methyl methacrylate (MMA) mixture. OMt content in the nanocomposite as well as the effect of QAS structure and dosage was investigated. Good dispersion of OMt in copolymer films was obtained as demonstrated by X-ray diffraction and partially exfoliated OMt structure was determined through transmission electron microscope. Final nanocomposites had 47 wt% solids contents. Nanocomposite containing 2.3 wt% OMt modified with two 18 carbons alkyl chain at excess QAS amount resulted in higher increments of thermal, mechanical, barrier properties and glossiness for coating applications.

Synthesis and antimicrobial activities of acrylamide polymers containing quaternary ammonium salts on bacteria and phytopathogenic fungi

Three series of acrylamide monomers/polymers containing quaternary ammonium salts (QASs), i.e., acrylamide QAS monomers (QDs), homopolymers of QDs (PQDs) and copolymers of QDs with acrylate monomer (PQDCs), were synthesized and employed in antimicrobial tests against both bacteria (Escherichia coli (E. coli) and Staphylococcus albus (S. albus)) and phytopathogenic fungi (Rhizoctonia solani (R. solani) and Fusarium oxysporum f. sp. cubense race 4 (Foc4)). The antibacterial activity of the QASs was evaluated by determining the minimum inhibitory concentration (MIC) against E. coli and S. albus by the TTC coloration method, and the antifungal activity was measured by mycelia growth inhibition as well as MIC and the minimum fungicidal concentration (MFC) values. The results indicated that PQD homopolymers and PQDC copolymers showed far better antimicrobial activities than QD monomers. PQDC copolymers by incorporating hydrophobic acrylate units into the main chain of polyacrylamide backbone displayed even better antimicrobial activities, depending on QAS structure and hydrophobic content. Moreover, polymers with benzyl group attached to nitrogen atom showed better inhibitory effect on bacteria and phytopathogenic fungi. The results could assist understanding and development of future design of antimicrobial polymers as potential fungicide agents to control plant disease.

Synthesis of cyclic carbonate from carbon dioxide and epoxides with polystyrene-supported quaternized ammonium salt catalysts

Polystyrene-supported quaternized ammonium salt catalysts (PS-alkyl-AX) were synthesized and characterized by various physicochemical analytic methods such as EA, FT-IR, XPS, and SEM. The reactivity of the catalysts was investigated for the synthesis of allyl glycidyl carbonate from CO2 and allyl glycidyl ether under mild reaction conditions. The PS-alkyl-AX catalysts showed good catalytic activity without using any solvent due to the synergistic effect of NH functional group and quaternary ammonium salt structure. Theoretical studies using density functional theory (DFT) was applied to investigate the reaction mechanism. The PS-hexyl-MeI catalyst was readily recoverable and reusable in subsequent reaction cycles without a significant loss in its activity.

Effect of the Phosphorus–Nitrogen-Containing Quaternary Ammonium Salt Structure on the Flammability Properties of Poly(methyl methacrylate)/Montmorillonite Nanocomposites

A series of phosphorus–nitrogen-containing quaternary ammonium salts (PNQASs) were designed and synthesized for use as clay modification reagents to investigate the impact of their chemical structu...

Surface Structures of PDMS Incorporated with Quaternary Ammonium Salts Designed for Antibiofouling and Fouling Release Applications

Poly(dimethylsiloxane) (PDMS) materials have been extensively shown to function as excellent fouling-release (FR) coatings in the marine environment. The incorporation of biocide moieties, such as quaternary ammonium salts (QAS), can impart additional antibiofouling properties to PDMS-based FR coating systems. In this study, the molecular surface structures of two different types of QAS-incorporated PDMS systems were investigated in different chemical environments using sum frequency generation vibrational spectroscopy (SFG). Specifically, a series of PDMS coatings containing either a QAS with a single ammonium salt group per molecule or a quaternary ammonium-functionalized polyhedral oligomeric silsesquioxane (Q-POSS) were measured with SFG in air, water, and artificial seawater (ASW) to investigate the relationships between the interfacial surface structures of these materials and their antifouling properties. Although previous studies have shown that the above-mentioned materials are promising contact-active antifouling coatings, slight variations of the QAS structure can lead to substantial differences in the antifouling performance. Indeed, the SFG results presented here indicated that the surface structures of these materials depend on several factors, such as the extent of quaternization, the molecular weight of the PDMS component, and the functional groups of the QAS used for incorporation into the PDMS matrix. It was concluded that in aqueous environments a lower extent of Q-POSS quaternization and the use of ethoxy (instead of methoxy) functional groups for QAS incorporation facilitated the extension of the alkyl chains away from the nitrogen atom of the QAS on the surface. The SFG results correlated well with the antifouling activity studies that indicated that the coatings exhibiting a lower concentration of longer alkyl chains protruding out of the surface can neutralize microorganisms more effectively, ultimately leading to better antifouling performance. Furthermore, the results of this study provide additional evidence that incorporated QAS exert their antimicrobial activity through a two-step interaction. The first step is the adsorption of the bacteria on the surface as a result of the electrostatic attraction between the negatively charged microorganisms and the positively charged QAS nitrogen atoms on the surface. The second step is the disruption of the cell membranes by the penetration of the QAS long, extended alkyl chains.

Synthesis and Hydroxyl Radicals Scavenging Activity of 2-Pyridine-acetyl-N-trimethyl Chitosan Chloride

A novel chitosan derivative with double quaternary ammonium salt-2-pyridine-acetyl-N-trimethyl chitosan chloride (PATMCS) was synthesized and the antioxidant activity of PATMCS against hydroxyl radicals was assessed. The results indicated that PATMCS had potent hydroxyl scavenging activity. The <TEX>$IC_{50}$</TEX> of PATMCS was 0.13 mg/mL. PATMCS showed 100% scavenging effect at a dose of 0.8 mg/mL which markedly better than that of N-trimethyl chitosan chloride (TMCS). It was confirmed that quaternary chitosan derivatives showed potent antioxidant activity. PATMCS has double quaternary ammonium salt structure in the molecules. Therefore, the antioxidant activity of PATMCS was better than TMCS. The above results are theoretically fundamental for further development and making use of chitosan resources to prepare new antioxidants.

Stereoisomerism in the series of isoindole-based quaternary salts

Steric structure of quaternary ammonium salts of the 3-[alkyl(aryl)amino]-1-[alkyl(aryl)iminio]-1H-isoindole series was studied by 1H NMR spectroscopy and X-ray analysis. The examined salts are characterized by E,E configuration of substituents with respect to the exocyclic C-N bonds, and the presence of ortho- and meta-substituents in the benzene rings on the nitrogen atoms gives rise to atropisomers. Sterically hindered N-(2,4,6-trimethylphenyl) derivative was found to exist as Z,Z isomer which undergoes irreversible thermal isomerization into the more stable E,E isomer through intermediate Z,E structure. The reactions of 1,1,3-trichloro-1H-isoindole with secondary aromatic amines having an electron-withdrawing substituent in the ortho position in the presence of organic bases (triethylamine, N,N-dimethylbenzylamine) are accompanied by decomposition of the latter and formation of unsymmetrically substituted salts of the 3-[alkyl(aryl)amino]-1-(dialkyliminio)-1H-isoindole series, which contain both arylamine residue and dialkylamino group and are also characterized by atropisomerism.

Phase transfer of Au nanoparticles using one chemical inducer: DDAB

Au nanoparticles in aqueous medium were transferred to organic solution via a remarkably simple one-step route under the effect of phase transfer inducer dimethyldioctadecylammonium bromide (DDAB). The feature of our method is that only one reagent (DDAB) was added purposely for the phase transfer. This is different from the literatures, where two reagents were used for the phase transfer of Au nanoparticles. One is an Au nanoparticle stabilizer; the other is a phase transfer agent. The effect of the inducer DDAB concentration was checked, and it was found that the optimum concentration of DDAB was 1 × 10−5 mol dm−3 for phase transfer of Au nanoparticles. The organosol, Au nanoparticle, and phase transfer were characterized by UV–vis spectra, TEM, EDS, ED, and FT-IR. Molecular structure of quaternary ammonium salt was used to explain the unique effect of DDAB for the phase transfer of nanoparticles.

Effect of the structure of quaternary ammonium salt radicals on the nitrite-chloride exchange

It has been shown that the NO3− and Cl− ions in methylpyperidine, cetylmorpholine, quinuclidine, and triethyl quaternary ammonium salts (QAS) are characterized by approximately equal exchange constants KCl−NO3− despite a significant difference in the structure of QAS. For methylpyperidine, cetylmorpholine, and triethyl salts, KCl−NO3− are almost equal, which can be attributed to the special features of ethyl radicals fixed into the cycles, which occupy a smaller volume and thus reduce the effect of the length of the third substituent, so that the parameters of the closest approach become nearer.

Designing Chiral Quaternary Ammonium Polymers: Novel Type of Polymeric Catalyst for Asymmetric Alkylation Reaction

Abstract Optically active polymers containing chiral quaternary ammonium salt structure in their main chain have been prepared by simple polycondensation reaction. These polymers were used as catalyst for asymmetric alkylation of N-diphenylmethylidene glycine tert-butyl ester.

Synthesis of Ion Conductive Networked Polymers Based on an Ionic Liquid Epoxide Having a Quaternary Ammonium Salt Structure

Various epoxy-based networked polymers having trimethylammonium bis(trifluoromethanesulfonyl)imide groups on the network were synthesized by heating a mixture of diepoxide, glycidyl trimethylammonium bis(trifluoromethanesulfonyl)imide (GTMATFSI), and diamine curing reagent. Ethylene glycol diglycidyl ether (EGGE), poly(ethylene glycol) diglycidyl ether (PEGGE), and poly(propylene glycol) diglycidy ether (PPOGE) were used as diepoxides, and ethylene glycol bis(3-aminopropy) ether (EGBA), poly(ethylene glycol) diglycidyl ether bis(3-aminopropyl ether) (PEGBA), and polypropylene glycol bis(2-aminopropyl ether) (PPOBA) were used as diamine curing reagents. The obtained networked polymers having quaternary ammonium structure showed high thermal stability, low crystallinity, low glass transition temperature, and good ionic conductivity. In particular, the networked polymers consisting of poly(ethylene glycol) segments showed high ionic conductivity (>1.0 × 10−3 S/m) at room temperature.