Quarternary Ammonium Salts Research Articles

WITHDRAWN: Study on cold-mix cement asphalt emulsion concrete by using lignin quaternary ammonium salt cation asphalt emulsion

Abstract The paper analyzed and compared the structure formation process of cement asphalt emulsion mixture made from anion asphalt emulsion, that has been in use before, with that of cement asphalt emulsion mixture made from cation asphalt emulsion, and based on the results of such analysis and comparison, was produced lignin quarternary ammonium salt cation asphalt emulsion and was determined the mixing ratio of the cold-mix cement asphalt emulsion concrete which is made from this.

Chloride Salts of Triethyl- and Benzyl-Triethyl-Ammonium: A New Antifungal for Giant Bamboo <i>(Dendrocalamus asper) </i>Preservation

In this study, quarternary ammonium salts based on triethylammonium and benzyltriethylammonium cations with the anion of chloride are successfully used for giant bamboo (Dendrocalamus Asper) preservation. These salts are new biocides as well as new salts which penetrate bamboo well. The prepared salts with hydrogen and benzyl substituent at the cation and consisted of chloride anion, exhibited fungicidal activity against Aspergillus Flavus. The effective and lethal doses were measured by the agar-plate method. In their activity against bamboo degrading fungi, salt of benzyl-triethyl-ammonium chloride was comparable with commercially available benzalkonium chloride and didecyldimethylammonium. Keywords: Triethylammonium, Benzyltriethylammonium, chloride, antifungal, and giant bamboo (Dendrocalamus Asper) and Aspergillus Flavus

Study on the Δ3 - Δ2 Isomerization During Preparation of Cefuroxime Double Ester Prodrugs

Δ3->Δ2 Isomerization during preparation of cephalosporin ester prodrugs has been frequently reported. Methods to eliminate the isomerization must be established. In the course of preparing cefuroxime double ester prodrugs, quarternary ammonium salts with different counter ions were used as catalysts for alkylations and their effects on the isomerization were compared. The structures ofΔ3 andΔ2 isomeric esters 1a and 1b were identified with 1H-1H COSY 2D NMR and DEPT 135 NMR.The degree of isomerization during alkylation was monitored with HPLC. It was demonstrated that tetrabutyl ammonium hydrogen sulfate (TBA+HS04-) was a better catalyst than TBA+I-in regard to preventing any isomerization. The desired cefuroxime double ester 1a was obtained as a sole product in this reaction when the molar ratio of TBA+ HSO4- to cefuroxime sodium was beyond 0.35. We have successfully eliminated theΔ3->Δ2 isomerization commonly reported for preparation of cephalosporin esters.

Synthesis and characterization of aliphatic polysulfides by interfacial polycondensation of sodium tetrasulfide with dichloroalkanes in the presence of quaternary onium salts

Poly(alkylenetetrasulfide) [poly(R-S4-R)] polymers with R = Me, Et, or Bu are prepared from alkylene dichloride and sodium tetrasulfide by an interfacial polycondensation technique using two quarternary ammonium salts as phase transfer catalysts. FT-IR, X-ray, and elemental analysis have characterized the synthesized polymers. Thermal properties were measured by thermogravimetric analysis and calorimetric differential scanning. Swelling procedure was used to investigate the solvent resistance of the polymers.

Rh-Catalyzed tandem C-C/C-N bond formation of quinoxalines with alkynes leading to heterocyclic ammonium salts.

An efficient Rh-catalyzed oxidative C-H activation/annulation of 2-arylquinoxalines with internal alkynes is described using Cu(OAc)2·H2O and AgBF4 to afford a diverse variety of substituted quarternary ammonium salts at room temperature. The mechanism of the protocol is established on the basis of isolation of the 5-membered rhodacycle intermediate and kinetic isotope studies. The mild reaction conditions, substrate scope and functional group diversity are the salient practical features.

Fluorescent Conjugated Polymer/Quarternary Ammonium Salt Co-assembly Nanoparticles: Applications in Highly Effective Antibacteria and Bioimaging.

Bacterial resistance is one of the very severe factors that threaten human health. It is of great significance to construct a simple, highly effective, biocompatible, and cost-efficient therapeutic route. In this paper, a new method was constructed to prepare cationic nanoparticles, and fluorescent conjugated polymer coassembly nanoparticles CA-CPNs were designed and synthesized on the basis of the model conjugated polymers, PFVBT, and the model quarternary ammonium salts, cationic surfactant cetyltrimethylammonium bromide CTAB. PFVBTs were designed and synthesized in only three steps. CTAB is commercially available. By the reprecipitation method, the PFVBTs form the core and CTAB forms a shell on the surface of CA-CPNs by hydrophobic interaction. Importantly, when incubated with bacteria, the positively charged CA-CPNs can combine with bacteria, physically destroy the bacterial membrane, and kill bacteria without the requirement of light or chemical energy. When 0.80 μg/mL CA-CPNs were incubated for 30 min with Escherichia coli, more than 91% bacteria were killed. Also, more than 96% Staphylococcus aureus were dead when incubated with 1.0 μg/mL CA-CPNs. In virtue of the bright red fluorescence, CA-CPNs were also successfully applied to image MCF-7 cell with good biocompatibility. Overall, a simple, cost-effective, and universal method was provided to prepare cationic fluorescent nanoparticles that are a promising nanomaterial for biomedical applications.

Investigation of Antimicrobial Properties of QASs+ (Novel Synthesis)

Quaternary ammonium salts (QASs) are bioactive materials known for their antimicrobial effects. However, it is difficult to provide desirable quaternary ammonium salts. Thus, firstly new quarternary ammonium salts which are not in the literature were synthesized and organoclays were prepared with different quarternary ammonium salts content. The organoclays included quaternary ammonium salts such as N,N-di (3-methyl butyl)-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-1), N,N-dipentil-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-2), and N,N-dihexcyl-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-3) which were newly synthesized for modification of Na+-montmorillonite (Na+-Mt) and were characterized by nuclear magnetic resonance spectroscopy (NMR). Synthesized organoclays were characterized by using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Characterization results proved that the modification is performed with high performance and as seen in the XRD results, the interstratum distances increased considerably and the diffraction angles decreased. The antimicrobial activity of the organoclays against Staphylococcus aureus and Escherichia coli were studied in detail and were obtained much larger inhibition zones than similar studies. QAS-3-Mt organoclay showed the maximum of antimicrobial activity against S. aureus and E. coli. As is known, organoclay comes among the fillers that play the most effective role in the synthesis of composite materials. In this context, the product we have synthesized is unique and can be used for many purposes.

STUDY OF EFFICIENCY OF ENDOWING ANTIMICROBIC PROPERTIES TO ELEMENTARIZED LINEN FIBERS

The authors have carried out the comparison of antimicrobic activity of flax fibers obtained by different methods and doped with preparations of silver or quarternary ammonium salts. The elementarized flax fibers obtained by the method of recurring cyclic deforming loads, differ essentially from the known analogs (cottonized fibers) because of the almost full absence of mechanical impurities. An important feature of elementarized flax fiber is the developed capillary-porous surface, which is confirmed by its high sorption capacity. The average mass length linear density, content of fibers of the fluff group, content of flax shive and also the hygroscopicity indexes were determined by the standard methods of material science. The level of whiteness was measured with "JENA" leukometer by “Carl Zeiss”. The quantitative output of antiseptic preparations ("Poviargole" and "Chlorhexidine") on fibers was controlled by the spectrophotometry method with the use of the spectrophotometer "Agilent 8453". The antimicrobic activity of the studied flax fibers was determined by estimating the change in coefficients of light-transmission of the solutions (containing nutrient medium for microbic cultures) before and after putting the studied samples into them. It is ascertained that elementarized flax fibers suppress the growth of microflora of the test cultures E. coli, Staphylococcus aureus and yeast-like fungus Candida albicans more effectively, than the mechanically cleaned ones.

Electrochemical methods for the determination of heparin

A review of studies on the determination of heparin in various samples (pharmaceuticals, biological fluids) by electrochemical methods of analysis in 1976–2014 is presented. Heparin is most often determined in pharmaceuticals by polarography using cationic dyes, and in biological samples, by differential pulse methods on non-stationary mercury electrodes. Works on the creation of heparin-selective electrodes coated with a polyvinylchloride membrane with quarternary ammonium salts are most promising; they can, probably, be used for the creation of portable devices for the determination of heparin.

Tuneable coumarin-NDI dyads as G-quadruplex specific light-up probes

Red fluorescence light up probes for G-quadruplex nucleic acids made by coumarin-naphthalene diimide dyads exhibit selectivity and sensitivity affected by the nature and length of the tethering spacers. Medium length alkyl spacers (≤7 C atoms) proved to be optimal when exciting the emitting naphthalene diimide by energy transfer from the coumarin chromophore, while longer spacers enhance the sensing efficiency by direct excitation of the naphthalene diimide. Moreover, hydrophilic tertiary amines improve the probe efficiency compared to their quarternary ammonium salt analogues and polyethylglycol spacers almost completely erase it.

New levulinic acid-based deep eutectic solvents: Synthesis and physicochemical property determination

Recently, deep eutectic solvents (DESs) have emerged as new and inexpensive ionic liquids (ILs) analogues. They possess attractive and similar solvent properties with traditional ILs. In present work a serials of DESs were prepared by pairing renewable levulinic acid (LA) as hydrogen donor with seven quarternary ammonium salts as hydrogen acceptor. The samples were further characterized in the temperature ranging from 293.15 to 333.15K at atmospheric pressure with the results of density (0.99891–1.17735gcm−3), dynamic viscosity (12.70–376.50mPas), electrical conductivity (0.35–8.27mScm−1), and refractive index data (1.44384–1.47273). The temperature dependence of these properties was explored and correlated with simple linear or Vogel-Fulcher-Tamman (VFT) models. The volume expansivities (β), molar volumes (Vm), molar refractions (Rm), and free volumes (fm) values have been calculated on the basis of density and refractive index data. The active energy of viscosity (Eη), molar electric conductivity (Λ), and ionicity were also determined. Partial structure-property relationship for DESs was also investigated. The tunable properties make DESs as a potential reaction medium, electrochemical process medium, solvent and absorbent. Therefore, the determination and correlation can provide relevant information for the engineering and industrial applications of DESs.

Aggregation induced emission amphiphile with an ultra low critical micelle concentration: fabrication, self assembling, and cell imaging.

A novel aggregation induced emission amphiphile is constructed, containing a tetraphenylethene hydrophobic moiety connected to a hydrophilic quarternary ammonium salt. Owing to an ultra low critical micelle concentration in water, the amphiphile tends to self assemble into well-defined organic nanoaggregates that exhibit intense fluorescence, stable dispersibility in dilute solutions, and excellent biocompatibility for cell imaging.

Synthesis of 3,5-dimethyl-1-prop-2-enylpyrazole under solid–liquid phase transfer catalytic conditions assisted by ultrasonic irradiation—A kinetic study

The synthesis of 3,5-dimethyl-1-prop-2-enylpyrazole was successfully carried out by reacting the 3,5-di-methyl pyrazole with 3-bromoprop-1-ene in small amount of KOH and organic solvent solid–liquid phase medium under phase transfer catalysis (PTC) and almost anhydrous conditions assisted by the ultrasonic irradiation in the 5h at 50°C. The main target of this carried work was to provide evidence that the reaction conditions by investigation of the kinetic behaviour, activation energy, reaction mechanism and the related parameters in the solid–liquid PTC reaction besides on to reduce time and temperature of reaction. A rational mechanism for the reaction has been derived base on the experimental result. This kinetic reaction follows pseudo first order rate law. A rate expression had developed to explain the kinetic behaviours from which the apparent rate constant (kapp) of the organic-phase reaction was obtained via investigated data. Kinetics of the reaction, including the effects of agitation speed, quantity of potassium hydroxide, quantity of water, temperature, quantity of tetraoctylammonium bromide (TOAB), volume of cyclohexanone, quarternary ammonium salts and organic solvents on the conversion of RBr and the apparent rate constant (kapp) were investigated in full length. Rational explanations for the resulting phenomena are also provided.

Evaluation of flame retardancy and shear resistivity characteristics of organoclay within acrylate polymer

The present work focuses on the effect of organically modified nanoclays on the fire resistance and processability characteristics of poly(methyl methacrylate) (PMMA). PMMA nanocomposite of cloisite 30B (methyl tallow bis-2 hydroxyethyl quarternary ammonium salt modifier) (C30B) was prepared by melt blending technique. A comparative study of flame retardant characteristics of virgin and filled matrix was carried out using cone calorimeter at a heat flux of 50 kW m−2, and the service temperature range was analyzed from thermogravimetric analysis. Parallel plate rheometry revealed the variation in processability as a function of C30B reinforcement and corresponding melt strength of the samples was evaluated through complex viscosity, storage, and loss modulus. Similarly, application-level modulus values were evaluated through viscoelastic properties by dynamic mechanical analysis. Supportive information for the observations from the above characterization was conducted using morphological studies by X-ray diffraction and transmission electron microscopy.

Development of Fullerene Based Molecules as an Acceptor Partner with P3HT for Opv Devices in a Thin Layer Organic Solar Cell

A fullerene and its derivatives have attracted much attention due to their attractive physical and chemical properties.1 The most notable features of fullerenes are their optical and electrochemical properties, which have recently been applied to an n-type material in organic photovoltaic (OPV) devices composed with p-type materials typified by p-conjugated polymers such as poly(3-hexylthiophene) (P3HT).2 Among fullerene derivatives, methyl [6,6]-phenyl-C61-butylate ([C60]-PCBM)3 has been widely used as the n-type material.4 We have reported that some OPV devices using fulleropyrrolidines as acceptor materials with P3HT, in particular, 1-(2-(2-methoxyethoxy)ethyl)-2-(2-methoxyphenyl)fulleropyrrolidine (1)5 and 1-([2,2'-bithiophen]-5-yl)-1-(2-(2-methoxyethoxy)ethyl) fulleropyrrolidine (2)6 showed higher power conversion efficiency (PCE) compared to those using [C60]-PCBM. Fulleropyrrolidines have a certain advantage over [C60]-PCBM from the standpoint of their stable nature under atmospheric conditions and the ease of producing various types of analogues. However, it was essential to use a special electrode which lacked the poly(3,4-ethylenedioxythiophene) :poly(styrenesulfonate) (PEDOT: PSS)7 layer to obtain high PCE. The role of HTL is believed to be to prevent the leak current from the active layer to the ITO electrode, thereby strongly contributing to the enhancement of the OPV performance, especially FF and Voc.8 Therefore, we investigated the interaction between the sulfonic acid group of PEDOT:PSS and nitrogen moiety of the fulleropyrrolidine to determine the reason why PEDOT:PSS caused the drop in PCE of fulleropyrrollidine based OPV devices. The study indicated that quaternary ammonium salt was formed on the interface of the active layer with PEDOT:PSS and this prevented the smooth hole transportation.6Inspired by the results, we hypothesized that a good OPV device might be produced using fulleropyrolidine derivatives if we could prevent the formation of such quarternary ammonium salt by PEDOT:PSS. We hypothesized that 2,5-diaryl-substiuted fulleropyrrolidine might become a good acceptor material because it might be difficult for the sulfonic acid group of PSS to access the nitrogen atom on the pyrrolidine ring due to enhanced steric hindrance of the N atom, and formation of quarternary ammonium salt would thus be avoided.Here, we report that the performance of the OPV devices using 2,5-diarylfulleropyrrolidines with P3HT and an ITO electrode with the PEDOT:PSS layer significantly depend on the stereochemistry of two substituents of the pyrrolidine ring.Three types of 2,5-diarylfulleropyrrolidine derivatives, i. e. 2,5-diphenylfulleropyrrolidine (3), 2,5-di(thiophen-2-yl) fulleropyrrolidine (4), and 2,5-di(thiophen-3-yl)fulleropyrrolidine (5) were synthesized and used as acceptor molecules with P3HT of OPV devices using two types of ITO electrodes. We discovered that PCE values of OPV devices prepared by 2,5-diarylfulleropyrrolidines as an acceptor partner with P3HT depended on both the stereochemistry and nature of the substituent: PCE of the devices using trans-2,5-diphenylfulleropyrrolidine (trans-3), cis-2,5-di(thiophen-3-yl)fulleropyrrolidines (cis- 5) and trans-2,5-di(thiophen-3-yl)fulleropyrrolidines (trans-5) were significantly lowered by PEDOT:PSS. On the other hand, cis-3, thiophen-2-yl-substituted compounds cis-4 and trans-4 worked in a different mode: these are independent of the presence of PEDOT:PSS and good PCE values were obtained for both isomers of 2,5-di(thiophen-2-yl) fulleropyrrolidine. Among tested compounds, trans-3 showed the best PCE which was superior to that of [C60]-PCBM. These results clearly indicate a rich possibility of fulleropyrrolidine type OPV devices with high PCE values with further investigation.9 References(1) C. A. Reed, R. D. Bolskar, Chem. Rev. 2000, 100, 1075.(2) S. Günes, H. Neugebauer, N. S. Sariciftci, Chem. Rev., 2007, 107, 1324. (3) J. C. Hummelen, B. W. Knight, F. LePeq, F. Wudl, J. Yao, C. L. Wilkins, J. Org. Chem., 1995, 60, 532. (4) F. Padinger, R. S. Rittberger, N. S. Saricifti, Adv. Funct. Mater., 2003, 13, 85.(5) K. Matsumoto, K. Hashimoto, M. Kamo, Y. Uetani, S. Hayase, M. Kawatsura, T. Itoh, J. Materials Chem., 2010, 20, 9226. (6) K. Yoshimura, K. Matsumoto, Y. Uetani, S. Sakumichi, S. Hayase, M. Kawatsura, T. Itoh, Tetrahedron, 2012, 68, 3605.(7) L. Groenendaal, F. Jonas, D. Freitag, H. Pielartzik, J. R. Reynolds, Adv. Mater., 2000, 12, 481.(8) M. C. Scharber, D. Mühlbacher, M. Koppe, P. Denk, C. Waldauf, A. J. Heeger, C. J. Brabec, Adv. Mater., 2006, 18, 789. (9) K. Yoshimura, K. Sigawara, S. Sakumichi, K. Matsumoto, Y. Uetani, S. Hayase, T. Nokami, T. Itoh, Chem. Lett., 2013, 42, 2009.

Synthesis of quarternary ammonium salts with dithiocarbamate moiety and their antifungal activities against Helminthosporium oryzae

Quaternary ammonium salts containing dithiocarbamate moiety were synthesized and evaluated for their antifungal activities against Helminthosporium oryzae. All the synthesized compounds showed moderate to promising fungitoxicity against the test. Some of the synthesized compounds inflicted antifungal activity greater than the standard fungicide. QUATS containing dithiocarbamate moiety were synthesized and evaluated for their antifungal activities against Helminthosporium oryzae. The synthesized compounds showed promising antifungal potential against the phytopathogenic test fungi. Hexyl-1-(2-hydroxy-3-(piperidine-1-carbonothioylthio)propyl)piperidinium bromide (5b) has shown ED50 value of 302\(\upmu\)g/ml, which was greater than the standard fungicide, Indofil M45(ED50 35\(\upmu\)g/ml) having only thiocarbamate moiety.

SYNTHESIS OF UNSATURATED ESTERS VIA HIGHLY EFFICIENT ESTERIFICATION CATALYZED BY POLYMER GRAFTED QUARTERNARY AMMONIUM SALTS AS TRIPHASE CATALYSTS

ABSTRACT A series of unsaturated esters were prepared via condensation of sodium carboxylates and alkenyl halide under the condition of macroporous polystyrene grafted quarternary ammonium salt as recyclable phase transfer catalyst, NaI as co-catalyst, Cu powder as inhibitor and H 2 O as solvent. Under optimal conditions, products yields are 78.2~ 96.0%. The catalyst can be convenient recycled and reutilized for about five times without losing its activity obviously. Keywords: green chemistry, triphase catalysis, polymer grafted quarternary ammonium salt, unsaturated ester INTRODUCTION Unsaturated esters are a kind of reactive plasticizer, which are important monomers in the manufacture of resin. At present, they continue to be in great demand in fields of aerospace, electronics and telecommunication. 1-2 Therefore, the development of new synthesis technology still holds great significance.In recent years, many efforts have been carried out on the synthesis of unsaturated ester. Among various approaches, the most preferred is condensation of alkali metal carboxylate with alkenyl halide. The original condensation were generally performed under high temperature and pressure, which was uneconomical and unsafe.

Nanoclay, intumescent flame retardants, and their combination with chemical modification for the improvement of the flame retardant properties of polymer nanocomposites

The flame retardancy of nanoclay, intumescent flame retardants (IFRs), and their combination with chemical modification is investigated in poly(methyl methacrylate) (PMMA) nanocomposites. 2,4,8,10-Tetraoxa-3,9-diphosphaspiro[5.5]-undecane-3,9-dioxide-disubstitutio-acetamide-N,N,N-triethyl-ammonium bromide (PDEABMMT) and 2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]-undecane-3,9-dioxide-disubstitutio-acetamide-N,N-dimethyl-N-hexadecyl-ammonium bromide (PDHAB-MMT) are prepared by ion exchange of sodium montmorillonite with phosphorus-nitrogen containing quarternary ammonium salts including PDEAB and PDHAB. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that PDHAB-MMT achieves tood dispersion in the PMMA matrix and the corresponding nanocomposites PMMA/PDHAB-MMT are formed. The incorporation of PDHAB-MMT into the PMMA matrix obviously improves the nanocomposite thermal properties. Cone calorimeter experiments indicate that the flame retardancy of nanoclay, IFRs, and their combination with chemical modification showed a 5%, 5%, and 9% reduction in the peak heat release rates of PMMA, respectively. The scanning electron microscopy and TEM images confirm that a compact and dense char is formed for PMMA/PDHAB-MMT nanocomposites after combustion. Open image in new window

Corrosion Inhibition of Aluminium using 3-Hydroxy flavone in the Presence of Quarternary Ammonium Salts in NaOH Medium

The anticorrosive effect of 3-Hydroxyflavone (3HF) in combination with quarternary ammonium bromide and iodide salts (QAB and QAI) for aluminium corrosion in NaOH medium was studied at the temperature range of 303K-323K using weight loss study, potentiodynamic polarization study and impedance spectroscopic measurements. The results revealed that the inhibition efficiency increases with the inhibitor concentration and it further increases on the addition of quarternary ammonium bromide and iodide salts. The enhanced inhibition efficiency of the inhibitor in the presence of quarternary ammonium salts may be due to synergistic effect. The adsorption process of 3HF on the aluminium surface obeys Langmuir's adsorption isotherm. The mechanism of adsorption is further supported by Scanning Electron Microscopic study (SEM).

Synthesis of soluble copolymers bearing ionic graft for alkaline anion exchange membrane

In this study, we report firstly the synthesis of a soluble quarternary ammonium salt and the corresponding graft copolymer P(VDF-g-QVBC) (poly(vinylidene fluoride-graft-quaternary ammonium-functionalized 4-vinylbenzyl chloride)), via atom transfer radical polymerization (ATRP) of QVBC from a PVDF macroinitiator. 1H NMR spectra indicate the successful synthesis of a series of copolymers with different graft ratios by varying the amount of monomers. The soluble quarternary ammonium-containing copolymers are composed of hydrophobic backbones and hydrophilic graft chains, which allow for favorable nano-scale phase separation during the solvent casting process. As a consequence, the resultant membrane exhibits excellent ionic conductivity as high as 45 mS cm−1, which suggests its potential application in alkaline anion exchange membrane fuel cells. In addition, semi-crystalline nature of PVDF macromolecules imparts the graft membrane excellent thermal and mechanical stability which are required for fuel cell application. Different from available studies of AEMs based on insoluble quarternary ammonium-containing copolymers, this study served as a model system for improving hydroxide conductivity from the viewpoint of self-generated nano-phase separation, and gives pioneering understanding of the morphology–property relationship in novel graft copolymer AEMs.