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quaternaryammoniumcompounds, etc ; halogens; liquids; solvents; Show all 4 Subjects
Abstract:
... A new deep eutectic solvent (DES) driven by halogen bonding (XB) was exploited. A family of eutectic mixtures in the liquid state was obtained by the combination of quaternary ammonium salts and dihalogens. The formation mechanism was discussed based on experiments and DFT calculations. It not only broadens the potential DES systems but unlocks the possibility of XB complexes as solvents. ...
quaternaryammoniumcompounds, etc ; iodides; organic chemistry; regioselectivity; solvents; Show all 5 Subjects
Abstract:
... We describe the use of phenyl trimethylammonium iodide (PhMe₃NI) as an alternative methylating agent for introducing a CH₃ group in α-position to a carbonyl group. Compared to conventional methylating agents, quaternary ammonium salts have the advantages of being nonvolatile, noncancerogenic, and easy-to-handle solids. This regioselective method is characterized by ease of operational setup, use o ...
quaternaryammoniumcompounds, etc ; hydrogen bonding; organic chemistry; thermodynamics; Show all 4 Subjects
Abstract:
... Many synthetic methods that use fluorinated alcohols as solvents have been reported, and the fluorinated alcohols have been found to be crucial to the success of these methods. In addition, there have been reports indicating that adding a weakly coordinated fluorine-containing anion, such as BF₄–, PF₆–, or SbF₆–, to fluorinated alcohols can improve yields. The boosting effect of fluorinated alcoho ...
quaternaryammoniumcompounds, etc ; analytical chemistry; chromatography; mass spectrometry; pesticides; Show all 5 Subjects
Abstract:
... The monitoring of pesticide residues in water sources is essential because of their increased worldwide demand in agriculture and their subsequent detection in waters. Pesticide residues in water matrices are traditionally determined by multiresidue methodologies based on chromatography coupled to mass spectrometry. However, for quaternary ammonium pesticide residues, as highly polar compounds, th ...
quaternaryammoniumcompounds, etc ; Suberea; alkaloids; cytotoxicity; leukemia; mice; moieties; Show all 7 Subjects
Abstract:
... Two new bromotyrosine alkaloids, ma'edamines E (1) and F (2), were isolated from an Okinawan marine sponge Suberea sp., and their structures were elucidated by the analyses of spectroscopic (UV, IR, and NMR) and spectrometric (MS) data. Ma'edamines E (1) and F (2) are the second and third examples of natural products possessing an N-alkyl-3,5-diethyl-2-propylpyridinium moiety. Ma'edamine F (2) is ...
quaternaryammoniumcompounds, etc ; colitis; cytotoxicity; fluorine; research; transcription (genetics); Show all 6 Subjects
Abstract:
... In order to obtain new dihydrocoptisine-type compounds with stable structure and activating XBP1 transcriptional activity, (±)-8-trifluoromethyldihydrocoptisine derivatives as target compounds were synthesized from quaternary ammonium chlorides of coptisine alkaloids as starting materials by a one-step reaction. The structures of the synthesized compounds were confirmed by ¹H-, ¹³C-, and ¹⁹F-NMR a ...
quaternaryammoniumcompounds, etc ; cholesterol; extrusion; ferrocenes; oxidants; oxidation; sonication; surfactants; Show all 8 Subjects
Abstract:
... Quatsomes are a class of nonphospholipid vesicles in which bilayers are formed from mixtures of quaternary ammonium (QA) amphiphiles and sterols. We describe the formation of oxidation and acid-sensitive quatsome-like vesicles and other bilayer assemblies from mixtures of a ferrocenylated QA amphiphile (FTDMA) and several cholesterol derivatives. The influence of the sterol and the preparation met ...
quaternaryammoniumcompounds, etc ; Escherichia coli; adhesion; cellulose; chemical bonding; zwitterions; Show all 6 Subjects
Abstract:
... At present, some multifunctional and smart materials equipped with both “bacteria-killing” and “bacteria-defending” functions have been created to meet the demands of some particular application areas. However, most of these materials were either biologically incompatible or required intricate crafting. In this paper, a finishing agent containing quaternary ammonium lactone ring and NCO groups was ...
quaternaryammoniumcompounds, etc ; anion exchange; anion-exchange membranes; nanofibers; tensile strength; Show all 5 Subjects
Abstract:
... A bead-on-string electrospinning strategy is proposed to solve the dilemma of unstable conduction channel while improving the OH⁻ conductivity of anion exchange membranes (AEMs). Here, poly (aryl ether ketone)-based AEMs are synthesized via N-spirocyclic quaternary ammonium modification, and then processed by electrospinning and sparingly soluble techniques. N-spirocyclic cations are induced to or ...
quaternaryammoniumcompounds, etc ; Populus; hydrogen bonding; lactic acid; lignin; lignocellulose; solubility; Show all 7 Subjects
Abstract:
... Deep eutectic solvents (DESs) composed by carboxylic acids and quaternary ammonium salts are potential candidate for lignocellulose dissolution and pretreatment. To both explore the most efficient DESs for lignocellulose dissolution and pretreatment as well as unveil the process mechanism, DESs composed by carboxylic acids as the hydrogen bond donors (HBDs) and quaternary ammonium salts as the hyd ...
quaternaryammoniumcompounds, etc ; electrolytes; energy; epichlorohydrins; ionization; lithium; polymers; thermal stability; Show all 8 Subjects
Abstract:
... Based on gelling matrices and ionic liquids (ILs), monolithic ionogel electrolyte membranes (MIEMs) have become a research focus. However, further application is limited by lack of functional matrices. Herein, we proposed the introduction of an ionized polymer, i.e., polyether polymer with side-chain ionic groups obtained via the reaction of quaternary ammonium with uncrystallizable poly (epichlor ...
quaternaryammoniumcompounds, etc ; biomass; dispersibility; electrostatic interactions; hydrophilicity; hydrophobicity; lignin; straw; Show all 8 Subjects
Abstract:
... Hydrophobic coatings are widely used in a variety of materials surfaces. However, it remains a great challenge for the non-toxic and environmentally-friendly production of hydrophobic coatings. Herein, two nano-scale spherical lignin/SiO₂ composite particles are synthesized based on the electrostatic interaction and the steric hindrance effect inspired by the self-protection of straw. Introduction ...
quaternaryammoniumcompounds, etc ; ammonium; ammonium salts; lithium; nanofiltration; polyamides; salt lakes; Show all 7 Subjects
Abstract:
... The efficient separation of Li⁺/Mg²⁺ is the key to lithium extraction from salt lake brine. Herein, a multi-amino quaternary ammonium salt (3,5-dimethylhydrazide-benzyl trimethyl ammonium bromide, DHTAB) was designed and synthesized to modify pristine polyamide (PA) nanofiltration membranes. DHTAB was grafted on the surface of the PA nanofiltration membrane to construct a positively selective laye ...
quaternaryammoniumcompounds, etc ; biopolymers; derivatization; esterification; macroalgae; pandemic; polysaccharides; research; toxicity; Show all 9 Subjects
Abstract:
... The global pandemic that started at the end of 2019 highlighted the need to create new biocidal products. Seaweeds are highly available non-toxic macromolecules of great interest in several industries and have remarkable biological properties, but still underexplored. Chemical modification in the structure of these biopolymers significantly improves their properties and confers high efficiency aga ...
quaternaryammoniumcompounds, etc ; films (materials); fluorides; ionic liquids; phase transition; temperature; Show all 6 Subjects
Abstract:
... In this work, a simple and efficient approach has been developed for preparing γ-PVDF films with a wide range of thickness based on the spontaneous diffusion of ionic liquids (ILs) into the α-PVDF matrix. It involves three steps: (i) preparation of α-PVDF films, (ii) surface coating of the resultant α-PVDF films with ionic liquids or quaternary ammonium solution, and (iii) annealing the surface mo ...
quaternaryammoniumcompounds, etc ; chlorides; ethyl ether; ion exchange; molecular dynamics; porosity; Show all 6 Subjects
Abstract:
... Recently there has been considerable interest in the utilization of covalent-organic frameworks (COFs) as ion-exchange membranes. While rapid ion conduction is experimentally observed in COF membranes, the underlying mechanism remains elusive. Herein, we report a molecular simulation study on chloride ion (Cl⁻) conduction in four COF membranes functionalized with quaternary ammonium groups (QA-2, ...
quaternaryammoniumcompounds, etc ; air; ammonium; composite polymers; energy; friction; hydrophilicity; lubrication; Show all 8 Subjects
Abstract:
... Multiple functional coating is urgently needed in complex service surroundings to meet various requirements. In this work, a brush-like amphiphilic copolymer of poly methacryloxyethyl dimethyl butyl ammonium bromide–polydimethylsiloxane (pMDBAB–PDMS) was synthesized to construct an environment-adaptive multifunctional coating based on the copolymer via the UV-curing method. The special molecule ch ...
quaternaryammoniumcompounds, etc ; anion-exchange membranes; batteries; electric potential difference; hydrophilicity; hydrophobicity; Show all 6 Subjects
Abstract:
... Neutral aqueous organic redox flow battery (NAORFB) stands out as one of the most prospective mass energy storage options. The main limitations of large-scale storage regarding the NAORFB lie in the low Na⁺/Cl⁻ conductivity of membrane in pH7 systems, which leads to a lower voltage efficiency. Herein, quaternary ammonium functionalized fluorinated poly (arylene ether) (QAFPAE-x) anion exchange mem ...
quaternaryammoniumcompounds, etc ; X-radiation; chlorides; electric field; hydrogen bonding; polymers; spectroscopy; Show all 7 Subjects
Abstract:
... A polymer electrolyte brush is a reasonable platform to confine water molecules within a nanoscopic area to study their role in the function of interacting media because of their adjustable nanospace and charge by changing the in-plane density and side chains of the brush. Here, we demonstrate how the in-plane spacing of cationic polymer brush chains, poly[2-(methacryloyloxy)ethyltrimethylammonium ...
quaternaryammoniumcompounds, etc ; ammonium; composite polymers; durability; electric potential difference; phosphoric acid; Show all 6 Subjects
Abstract:
... Phosphoric acid (PA)-doped polymer electrolyte membranes are the most promising materials for high-temperature proton exchange membranes (HT-PEMs). However, their development is subject to the compromise between proton conductivity and phosphoric acid (PA) doping level. Here, an ether-free QPAF-4 membrane (a copolymer containing perfluoroalkylene and fluorenyl groups with pendant ammonium groups) ...