Alkyl Quaternary Ammonium Salts Research Articles

Risk assessment related to the presence of benzalkonium chloride (BAC), didecyldimethyl ammonium chloride (DDAC) and chlorates in fish and fish products.

In compliance with Article 31 of Regulation (EC) No 178/2002, EFSA received a mandate from the European Commission to prepare a statement on the risk assessment related to the presence of benzalkonium chloride (mixture of alkylbenzyldimethylammonium chlorides with alkyl chain lengths of C8, C10, C12, C14, C16 and C18) (BAC), didecyldimethylammonium chloride (mixture of alkyl-quaternary ammonium salts with alkyl chain lengths of C8, C10 and C12) (DDAC) and chlorates in fish and fish products. Within EFSA's annual chemical data collection, EFSA collected monitoring data for the residues of BAC, DDAC and chlorates from EU Member States, Iceland and Norway performed a statistical evaluation, providing estimated residue values for each substance in/on fish and fish products, at the percentile appropriate for the number of the available samples. Based on the information collected, EFSA performed an acute and chronic exposure assessment for EU consumers for BAC, DDAC and chlorates at the lower-bound, medium-bound and upper-bound scenarios resulting from the consumption of fish and fish products. EFSA did not identify potential consumer health risks associated to residues of the substances found in fish and fish products.

Self-Healing Hydrogels Fabricated by Introducing Antibacterial Long-Chain Alkyl Quaternary Ammonium Salt into Marine-Derived Polysaccharides for Wound Healing

The development of hydrogels as wound dressings has gained considerable attention due to their promising ability to promote wound healing. However, in many cases of clinical relevance, repeated bacterial infection, which might obstruct wound healing, usually occurs due to the lack of antibacterial properties of these hydrogels. In this study, we fabricated a new class of self-healing hydrogel with enhanced antibacterial properties based on dodecyl quaternary ammonium salt (Q12)-modified carboxymethyl chitosan (Q12-CMC), aldehyde group- modified sodium alginate (ASA), Fe3+ via Schiff bases and coordination bonds (QAF hydrogels). The dynamic Schiff bases and coordination interactions conferred excellent self-healing abilities to the hydrogels, while the incorporation of dodecyl quaternary ammonium salt gave the hydrogels superior antibacterial properties. Additionally, the hydrogels displayed ideal hemocompatibility and cytocompatibility, crucial for wound healing. Our full-thickness skin wound studies demonstrated that QAF hydrogels could result in rapid wound healing with reduced inflammatory response, increased collagen disposition and improved vascularization. We anticipate that the proposed hydrogels, possessing both antibacterial and self-healing properties, will emerge as a highly desirable material for skin wound repair.

Erratum to: Successive Modification of Montmorillonite with Quaternary Alkylammonium Salts of Various Structures as a Method of Preparing Nanofillers for in situ Synthesis of Polymer Nanocomposites (SILAR)-Deposited CuO Thin Films of Nitrobenzene

Erratum to: Successive Modification of Montmorillonite with Quaternary Alkylammonium Salts of Various Structures as a Method of Preparing Nanofillers for in situ Synthesis of Polymer Nanocomposites (SILAR)-Deposited CuO Thin Films of Nitrobenzene

Hybridization of Oligonucleotide Probes in Aqueous Solutions: Washing in Buffers Containing Quaternary Ammonium Salts.

In this protocol, hybridization is first performed in conventional aqueous solvents at a temperature well below the melting temperature, and the hybrids are then washed at higher stringency in buffers containing quaternary alkylammonium salts. TMACl is used with probes that are 14-50 nt in length, whereas TEACl is used with oligonucleotides that are 50-200 nt in length.

Successive Modification of Montmorillonite with Quaternary Alkylammonium Salts of Various Structures as a Method of Preparing Nanofillers for in situ Synthesis of Polymer Nanocomposites

Successive Modification of Montmorillonite with Quaternary Alkylammonium Salts of Various Structures as a Method of Preparing Nanofillers for in situ Synthesis of Polymer Nanocomposites

Selective flocculation performance of amphiphilic quaternary ammonium salt in kaolin and bentonite suspensions

In the present work, a type of amphiphilic alkyl quaternary ammonium salt, dimethyl distearylammonium chloride (DAC), was introduced and used as a selective flocculant in kaolin and bentonite suspensions. The selective flocculation property was evaluated by turbidity tests, floc size measurements, zeta potential variation, contact angle measurements and scanning electron microscopy (SEM) observation. The results indicated that an appropriate amount of DAC could achieve selective flocculation at alkaline condition. Based on the experimental facts from size, zeta potential and contact angle measurements, the different flocculation mechanisms of kaolin and bentonite were also investigated. For kaolin suspension, charge neutralization was quite predominant. At different pH level, a low dosage (45 mg/L) of DAC always caused excellent flocculation while high dosage (> 45 mg/L) gradually leaded to restabilization owing to the electrostatic exclusion. For bentonite suspension, bridging effect played the key role. Under acidic condition, bentonite particle always performed good flocculation phenomena at different DAC dosages. But it would gradually lead to enhanced flocculation efficiency from poor to good with increasing the dosage of DAC under alkaline condition. As a result, DAC showed the selective flocculation performance by controlling the dosage of DAC and pH, which provided us the guidance on designing more effective selective flocculant in complex clay mixture system.

A simple method of simultaneously endowing paper or fluff pulp with both high softness or appropriate fluffing properties and antimicrobial properties

As the living standard improves, disposable sanitary and household paper requires not only softness or easy to fluff in a dry state, but also good antibacterial property. In this study, a series of alkyl quaternary ammonium salts (AQAS), a kinds of antibacterial-debonding agents, were synthesized by using a two-step process. The SN2 nucleophilic substitution reaction was designed between triethanolamine and sulfoxide chloride, and followed subsequent quaternization by tertiaryamines with different long alkyl chains. The obtained products can be used as an antibacterial and softening/debonding agent for improving the performance of paper or fluff pulp. The results showed that these new compounds can endow antibacterial function and high softness to paper or control appropriate burst strength to fluff pulp. These AQAS products can be not only used in daily disposable sanitary products, but also have potential applications in other products such as glass spacer paper, advanced household paper, or antibacterial tissue products to prevent microbial contamination.

Vermiculite modified with alkylammonium salts: characterization and sorption of ibuprofen and paracetamol

In this work, the clay mineral vermiculite (VT) was treated using the bromide form of quaternary alkylammonium salts—ethylhexadecyldimethylammonium (EHDDMAB), hexadecyltrimethylammonium (HDTMAB), tetradecyltrimethylammonium (TDTMAB) and tetrabutylammonium (TBAB), in order to obtain the organo-vermiculites (OVT) named as VT-EHDDMA, VT-HDTMA, VT-TDTMA and VT-TBA, respectively. These sorbents and the precursor VT were characterized using several techniques which allowed to infer the intercalation of the alkylammonium salts in the interlayer space of VT, except VT-TBA, and these materials were evaluated as sorbents for ibuprofen and paracetamol. VT and OVT presented no significant interactions with paracetamol and sorbed less than 10% of the initial concentration. On the other hand, two OVT sorbents demonstrated high efficiency in the sorption of ibuprofen, and the maximum percent removal was higher than 92% for VT-EHDDMA and VT-HDTMA, with a maximum sorption capacity of 52 ± 2 mg g−1 (VT-EHDDMA) and 54 ± 2 mg g−1 (VT-HDTMA), whereas 16 ± 2 mg g−1 was observed for VT. These results suggest that the low-cost OVT could be considered as appropriate sorbent for ibuprofen removal from aqueous medium, and probably as a promising sorbent for drugs of a wide polarity range, with neutral, acid and basic characteristics.

Surface Crystal Growth of Perovskite Nanocrystals via Postsynthetic Lead(II) Bromide Treatment to Increase the Colloidal Stability and Efficiency of Light-Emitting Devices.

The surface modification of metal halide perovskite nanocrystals (NCs) significantly impacts their optical properties and colloidal stability. This subsequently affects the performance of light-emitting devices (LEDs). Therefore, numerous surface passivation techniques like ligand exchange and metal halide doping have been explored to passivate the surface defects of perovskite NCs and obtain highly efficient LEDs. In this study, we demonstrated the postsynthetic metal halide doping treatment using lead(II) bromide (PbBr2) to passivate the surface defects of the CsPbBr3 NCs at a moderate reaction temperature of 80 °C. The alkyl quaternary ammonium salt, didodecyldimethylammonium bromide (DC12AB), enabled the complete dissolution of PbBr2 in a nonpolar solvent, toluene. Because of surface crystal growth, the particle sizes of the PbBr2-doped CsPbBr3 NCs were higher than those of the as-synthesized CsPbBr3 NCs. The photoluminescence quantum yield of the CsPbBr3 NCs drastically increased from 26.8 to 83.9% after the PbBr2 doping treatment. Moreover, the PbBr2-doped CsPbBr3 NCs possessed long-term colloidal stability of more than 2 months that indicates the strong bonding between the NCs and ligands. We observed that the alkyl chain length of the quaternary alkyl ammonium salts affected the luminance and device stability during operations. In this study, a promising strategy was devised to achieve highly luminescent perovskite NCs with excellent colloidal stability that can enhance the performance of LEDs.

Methyl transfer in quaternary alkylammonium salts, derivatives of 1,4:3,6-dianhydrohexitols

An unexpected side-reaction took place during the synthesis of quaternary ammonium salts with O-triflyl derivatives of 1,4:3,6-dianhydrohexitols and tertiary alkylamines. The products were identified as tertiary amine derivatives of 1,4:3,6-dianhydrohexitol and tetraalkylammonium triflate. It was found that formation of the products was the consequence of the methyl group migration from QAS formed to the amine present in excess in the reaction mixture. Such reaction is a case of transquaternization, in which the exchange of the methyl group between two amines occurs.

Epoxide as precatalyst for metal-free catalytic transesterification

Transesterification of methyl esters was accelerated by an in situ-generated metal-free catalyst comprising a quaternary alkylammonium salt and an epoxide. The combination of a quaternary alkylammonium acetate and glycidol is optimal, and various esters were synthesized from methyl esters with alcohols in good to excellent yield. Analysis of the catalyst solution revealed that basic species are generated by the ring-opening reaction of epoxide.

Microwave/ultrasound-assisted modification of montmorillonite by conventional and gemini alkyl quaternary ammonium salts for adsorption of chromate and phenol: Structure-function relationship

Butane-1,4-bis(dodecyl dimethyl ammonium bromide) (gBDDA) and dodecyl trimethyl ammonium bromide (DTMA) in same stoichiometric amounts were applied to modify montmorillonite (Mt) under microwave and ultrasound conditions. The composition and structure of products were obtained through multiple characterizations including XRD, FTIR, TG/DTG, SEM, TEM, and N2 adsorption/desorption measurements, and the adsorption performance of chromate and phenol on these products were also investigated. Intercalations of gBDDA and DTMA into interlayer space of Mt were observed, but the amount of anchored modifier on the external surface was larger for gBDDA compared with DTMA when the stoichiometric amount of modifier larger than 1.0 times cation exchange capacity of Mt was added. Although there was no significant difference in morphology among products, the interlayer space distance, specific surface area, and pore size distribution were closely associated with the species and amount of applied modifier. Adsorption of phenol on products through partition mechanism relied on not only organic content, but also the configuration of modifier. Meanwhile, adsorption of chromate mainly depended on the presence of counter ion (bromide), which accounted for the high adsorption capacity and initial adsorption rate on gOMt-0.75. The fitting parameters of adsorption results using pseudo-second order model and Freundlich model suggested that gBDDA-modified Mt could sequester phenol or chromate in the faster manner with higher affinity. Compared with the conventional surfactant such as DTMA, the study revealed that, using gemini surfactant such as gBDDA to modify Mt would significantly reduce or even has the potential to eradicate the secondary pollution by modifier release during adsorption process. This study provides a new direction for Mt modification intended to be used as adsorbents to treat polluted water with high standards such as drinking water.

Quaternary Alkylammonium Salts as Cleaning and Disinfectant Agents

AbstractMonomeric and dimeric quaternary alkylammonium salts are a wide group of cationic surfactants with prominent surface, biocidal and anticorrosion properties. The methods of synthesis, structure and behavior in solution of these compounds is presented in the article. Antimicrobial activity, biodegradability, toxicity, aquatoxicity and hemolytic activity of quaternary alkylammonium salts is discussed. The preparation, application and antimicrobial activity of cleaning and disinfectant products containing alkylammonium salts are described in details. A special attention has been devoted to EU regulations concerning biocidal products. The alkylammonium salts that can be used in biocidal products, placed on the list in Article 95 of the Biocidal Products Regulation (BPR) are given. Maximum residue limits (MRL) for didecyldimethylammonium chloride and benzalkonium chloride are given and commented.

Latest progress on the typical mesoporous Si-based solid acid catalysts

Serious environment and safety issues by the wide application of inorganic mineral acids have attracted worldwide attention from fundamental science and application point of view. Under such circumstances, the development of the solid acid catalysts is a very hot topic currently. The ideal solid acid catalysts possess appropriate Bronsted and Lewis acidic nature, good porosity, high stability and unique morphology. Among them, the morphological nanostructure of catalysts is one of the important factors that can have a profound influence on their catalytic performance. Compared with a number of other supports of the solid acid catalysts, the silica-based materials are considered as promising candidates because of their diverse composition, physicochemical property and morphology as well as excellent porosity property. Among them, mesoporous silica-based materials possess lager pore compared with the microporous silica materials (e.g., ZSM-5, H-beta, etc.). They enable to catalyze reactions efficiently involving bulky substrates and/or products, and facilitate mass transfer. Meanwhile, the larger pore favors the dispersion of the active sites and hinders the accumulation of coke on the surface to avoid pore blocking. As a result, one of the important strategies to prepare novel solid acid catalysts is to immobilize the active sites on mesoporous silica materials. The as-prepared mesoporous silica-based solid acid catalysts have shown great potential for application in the field of environment, energy and industrial catalysis. In this paper, the latest progress on the morphology-controlled preparation of mesoporous silica−based materials and their applications in catalysis are summarized. In the case of the silica-based materials, it can be dated back to the early 1990s, and Mobil Company synthesized various M41S materials firstly (MCM-41, MCM-48 and MCM-50) by using the alkyl quaternary ammonium salt cationic surfactant as the template agent. Compared with the amorphous silica materials, M41S possess ordered mesoporous structure, uniform pore size (2‒5 nm), large pore volume and BET surface area (1000 m2 g-1). Subsequently, various SBA materials (such as SBA-15 and SBA-16) with large pore size were prepared successfully. It has attracted wide attention to functionalize the silica materials by incorporating the active sites and maintaining the morphological structure. With the development of silica-based materials, periodic mesoporous organosilicas (PMO) were synthesized by surfactant-directed sol-gel method, which opened a new pathway to prepare functional mesoporous silica materials. Up to now, a number of functionalized organosilica materials have been reported and exhibited great potential in the fields of catalysis, sensing, chromatography analysis, metal adsorption and bio-pharmacy etc. Herein, the mesoporous silica-based solid acid catalysts by the morphology-controlled preparation of functionalized organosilicas showed highly ordered, tubular or hollow spherical nanostructure by P123-directed sol-gel co-condensation. The as-prepared mesoporous silica-based solid acid catalysts possessed hydrophobic surface, excellent porosity property and strong Bronsted acidic nature. Moreover, the catalysts with well-defined morphology exhibited high catalytic performance for synthesis of the biomass-derived platform molecules or high value-added chemicals. Owing to the accelerated diffusion, transmission and improved accessibility of substrates to active sites, the mesoporous silica-based solid acid catalysts with hollow nanosphere morphology showed the highest activity compared with the tubular or ordered analogues. On the other hand, the covalent bond between active sites and silica framework can avoid the leaching issue of the solid acid catalysts. In addition, the hydrophobic character of alkyl-containing organosilica can reduce acid sites deactivation associated with adsorption of polar byproducts, which can improve the stability of as-prepared catalysts. To summarize, this review aims to provide important reference value for development of novel solid acid catalysts.

Organoclay applications and limits in the environment

Abstract This article gives an overview of the preparation, applications, and limits of organoclay materials in the environment field. Organoclays are obtained by the combination of clay minerals and surfactants (quaternary alkyl ammonium salts and others) and are appropriate candidates for the adsorption of organic contaminants such as pesticides, herbicides, and pharmaceuticals that are more and more found in the water resource despite wastewater treatments. This review article focuses on novel organoclay preparation methods based on the use of nonconventional nonionic surfactants and the interest and limits of these hybrid materials for the adsorption of organic compounds at both batch equilibrium and dynamical percolation experimental conditions.

Synthesis and characterization of quaternary ammonium based ionic liquids and its antistatic applications for diesel

To improve the diesel conductivity and avoid the electrostatic spark explosion/fire accidents, a series of room temperature ionic liquids (ILs) were synthetized by four kinds of long-chain alkyl quaternary ammonium salt (DTAC, TTAC, HTAC and STAC) and n-butyl naphthenate sulfonic acid using ultrasound method, which were added into the diesel as antistatic agents. Nuclear magnetic resonance spectrum (NMR), Fourier transform infrared spectrometer (FT-IR), thermogravimetric analysis (TGA) and element analysis (EA) were employed to characterize the structures and properties of the ILs, confirming the successful synthesis of the ILs. Experimental results indicated that the prepared ILs can significantly improve the diesel antistatic ability even at ppm level, while the ILs showed an acceptable effect on the diesel combustion performance. The mechanisms of action were also clarified and discussed based on the reverse micelles (RM) microstructures and physicochemical properties of the synthesized ILs. It should be noted that the new diesel antistatic agents have a few features such as high efficiency, lasting effects, mild reaction conditions and low cost, which is bound to have broad application prospect for diesel antistatic accordingly.

Quaternary alkylammonium salt incorporated 2D/3D mixed halide perovskite with highly enhanced photoluminescence and arrested iodide/bromide phase segregation

A mixed-halide (I/Br) 2D/3D perovskite is formed by incorporating bromide via quaternary alkylammonium salt and iodide via methylammonium iodide. The X-ray diffraction analysis reveals the 2D/3D mixed constitution, with both components having mixed halide stoichiometry. Importantly, this tetrabutylammonium incorporated material not only exhibits almost two orders of magnitude enhancement of photoluminescence intensity but concurrently a higher photo-stability (at the desirable bandgap of 1.77 eV) than the pure 3D mixed halide case. Moreover, a significant increase (from 8.8 ns to 63 ns) is observed in the lifetime of the photo-generated carriers in the mixed halide 2D/3D material.

Characterization of polymer/nanoclay composites via direct pyrolysis mass spectrometry

In this work, direct probe mass spectrometry, DP-MS, method was applied to investigate the characteristics of polymer/organoclay composites. For this purpose organically modified montmorillonites involving four different alkyl quaternary ammonium salts were incorporated into polylactide, poly(methyl methacrylate) and polyethylene matrices. The morphology of the composites were first analyzed by x-ray diffraction, XRD, and transmission electron microscopy, TEM, measurements. The temperature regions at which the organic modifier was lost during the pyrolysis of the organoclays and the polymer/organoclay composites were correlated with inter-layer spacing of the clay layers. It has been determined that the loss of organic modifier shifted to lower temperatures as the interlayer-spacing increased. As a consequence of broader inter-layer spacing, the extent of intercalation was improved leading to an increase in thermal stability of the matrix polymer. The results clearly showed that the DP-MS technique supplies strong evidences for the extent and type of dispersion of clay layers in the polymer matrices. In addition the technique allows identification of possible interactions between the polymer and the organic modifier.

Synthesis of Hierarchically Porous Zeolite Composites with Enhanced Catalytic Activity: Effect of Different Long-Chain Structure Directing Agents

A two-section temperature strategy was employed to achieve micromesoporous composites with five kinds of long-chain alkyl quaternary ammonium salts as single template. Zeolites with an ordered two-dimensional hexagonal mesopore and crystallized MFI domain were successfully obtained. Gemini quaternary ammonium salt surfactants C18N2 and C22N2 are effective in directing the structure of MCM-41 than CTAB at 100 °C and will transform to lamellar MFI structures at 150 °C gradually. While single quaternary ammonium salts C18N and C22N direct lamellar M41s at 100 °C and transform to mesoporous structure at a higher temperature of 150 °C, it is possible to get a composite of microporous and mesoporous material with a surface area as high as 1046 m2 g–1. Catalytic performance of typical hierarchical zeolites was evaluated by Claisen-Schmidt condensation of bulky reactants. The excellent conversion suggested the synergy effects of improved large molecule diffusion in mesopores and highly separated MFI domains as ca...

Quaternary Alkyl Ammonium Salt-Catalyzed Transformation of Glycidol to Glycidyl Esters by Transesterification of Methyl Esters

Catalytic transformation of glycidol while maintaining its epoxide moiety intact is challenging because the terminal epoxide that interacts with the hydroxyl group via a hydrogen bond is labile for the ring-opening reaction. We found that a quaternary alkyl ammonium salt catalyzes the selective transformation of glycidol to glycidyl esters by transesterification of methyl esters. The developed method can be applied to the synthesis of multiglycidyl esters, which are valuable epoxy resin monomers. Mechanistic studies revealed the formation of a binding complex of glycidol and quaternary alkyl ammonium salt in a nonpolar solvent and the generation of the alkoxide anion as a catalyst through the ring-opening reaction of the epoxide. Computational studies of the reaction mechanism indicated that the alkoxide anion derived from glycidol tends to abstract the proton of another glycidol rather than work as a nucleophile, initiating the catalytic transesterification. Payne rearrangement of the deprotonated glycid...