Diquaternary Ammonium Salts Research Articles

Dual-template synthesis of thinner-layered MCM-49 zeolite to boost its alkylation performance

MCM-49 zeolite has MWW toplological structure similar to MCM-22 and it possesses connatural more external acid sites, performing more advantages in solid acid catalysis. Herein, a thinner-layered C18-MCM-49 microsphere by using diquaternary ammonium salts (C18–6–6Br2, denoted as C18, or Cn6n series) in mixture sols was achieved. This C18-MCM-49 microsphere possesses a 1–2 µm particle size, for which the crystal sheets decrease to ∼200 nm in size and 5–20 nm in thickness, which originated from that more C18 molecules located in the half cups and supercages pores to achieve the separation of MWW layer thickness in the c direction. The C18-MCM-49 zeolite provides an ultra-large external surface area (212 m2•g−1) and mesopore volume (0.767 cm3•g−1), and compared with traditional MCM-49 (Sext = 133 m2•g−1, Vmes = 0.414 cm3•g−1), external surface area and mesopore volume were increased by 59.4% and 85.3%, respectively. Due to its thinner-layered structure, this C18-MCM-49 microsphere displays more active acid sites on the external surface, leading to an improved ethylbenzene selectivity (94.7%) and benzene conversion (34%) in alkylation reaction. By using synchrotron radiation Small-angle X-ray scattering, we further studied series of synthetic sols during aging period. The results prove the behavior of aluminosilicate species in the mixture plays critical role in thinner-layered MCM-49, specifically, the precursor fractal between 2 and 2.5 is a key factor in synthesizing MCM-49. Collectively, this result offers a convenient and valid way to synthesize other types of zeolites.

Synthesis of BEC-type germanosilicates with asymmetric diquaternary ammonium salts

This paper deals with the synthesis of germanosilicate zeolites using asymmetric diquaternary ammonium salts as organic structure-directing agents (OSDA). Seven pyrrolidinium and piperidinium derivatives were chosen, with different carbon chain lengths and different terminal groups linked to the nitrogen atoms. For each OSDA, the syntheses were performed with four different gel compositions, i.e. in fluoride or hydroxide media both in concentrated or diluted conditions. The products were identified using powder X-ray diffraction data (PXRD). The integrity of the structure-directing agents were verified using 13C liquid and solid-state NMR spectroscopy and thermogravimetric analyses. For one sample, the Rietveld method allowed us to localize the OSDA inside the pore and the fluoride ions inside the d4r composite building unit but, also inside the main 12-ring channels as proved by 19F solid-state NMR spectroscopy.

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.

Novel Gemini cationic surfactants as anti-corrosion for X-65 steel dissolution in oilfield produced water under sweet conditions: Combined experimental and computational investigations

Two new sequences of Gemini di-quaternary ammonium salts were synthesized characterized by FTIR and 1HNMR spectroscopic techniques and evaluated as corrosion inhibitor for X-65 steel dissolution in deep oil wells formation water saturated with CO2. The anti-corrosion performance of these compounds was studied by different electrochemical techniques i.e. (potentiodynamic polarization and AC impedance methods), Surface morphology (SEM and EDX) analysis and quantum chemical calculations. Results showed that the synthesized compounds were of mixed-type inhibitors and the inhibition capability was influenced by the inhibitor dose and the spacer substitution in their structure as indicated by Tafel plots. Surface active parameters were determined from the surface tension profile. The synthesized compounds adsorbed via Langmuir adsorption model with physiochemical adsorption as inferred from the standard free energy (ΔG°ads) values. Surface morphology (SEM and EDX) data for inhibitor (II) shows the development of adsorbed film on steel specimen. Finally, the experimental results were supported by the quantum chemical calculations using DFT theory.

Synthesis and Antimicrobial Evaluation of Symmetrical Diquaternary Ammonium Salts Bearing Bis-1,3,4-Oxadiazole Rings Moieties

Synthesis and Antimicrobial Evaluation of Symmetrical Diquaternary Ammonium Salts Bearing Bis-1,3,4-Oxadiazole Rings Moieties

Synthesis and Characterization of Piperazinium Polyelectrolytes Carrying Hydrophobic Functionalities: Effect of Counter Ion and Charge Density on Flocculation

Following our recent synthesis and characterization of three new cationic polyelectrolytes with subtle hydrophobic variability, this paper reports their physical and chemical properties in aqueous media in relation to their chemical structure. Aryl substituted cationic polyelectrolytes varying with their charge density are reported for the first time. Viscosity studies show that these polymers display typical polyelectrolytic behavior. The flocculation efficiency of the polyelectrolytes was investigated with different counter ions. The zeta potential of the polyelectrolytes indicates the charge of the mono and diquaternary ammonium salts which is supported by chloride analysis. The morphology of polymer before and after flocculation was investigated. The introduction of methylene group and quaternary nitrogen play an important role in the flocculation process. It was shown that increasing the hydrophobicity and charge density of the aryl substituted polymer affects the flocculation in the industrial tannery effluent and bentonite suspension.

Corrosion Inhibition of N80 Steel Using Novel Diquaternary Ammonium Salts in 15% Hydrochloric Acid

Three novel diquaternary ammonium salts with alkanediyl spacers of varying chain length were synthesized, and their corrosion inhibition effects on N80 steel in 15 wt % HCl solution were studied by weight loss measurement, electrochemical polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX). The results indicated that the inhibition efficiency increased with the inhibitor concentration and the length of hydrophobic spacer of the inhibitor. At 90 °C, the inhibition efficiency of diquaternary ammonium salt N,N′-octane-1,8-diyl-bisquinolinium dibromide reached about 91% at the inhibitor concentration of 0.01 mol/L. Potentiodynamic polarization curves indicated that all synthesized compounds acted as mixed-type inhibitors. The inhibition mechanism involved the formation of an inhibitor protective layer on the N80 steel surface by a Langmuir-type adsorption process. The presence of Br and N in chemical composition detected by EDX confirmed the adsorption of inhibitors on the N80 steel surface.

Three novel di-quaternary ammonium salts as corrosion inhibitors for API X65 steel pipeline in acidic solution. Part I: Experimental results

Three novel di-quaternary ammonium salts were synthesized, characterized, and tested as corrosion inhibitors for API X65 steel pipeline in 1M HCl. The inhibition effect of the prepared compounds was studied by EIS, Tafel polarization and weight loss measurements. Polarization curves revealed that the prepared compounds act as mixed type inhibitors. It was found that the inhibition efficiency increased with increasing the compound concentration and decreasing the temperature and also is dependent on the molecular structures. Adsorption of the prepared compounds on API X65 steel pipeline surface is a physical adsorption and obeys the Langmuir’s isotherm.

The Synergetic Interplay of Weak Interactions in the Ion‐Pair Recognition of Quaternary and Diquaternary Ammonium Salts by Halogenated Resorcinarenes

AbstractThe influence of halogens on the noncovalent interactions of different upper‐rim‐substituted hexylresorcinarenes with quaternary and diquaternary ammonium iodide salts was investigated in the gas phase by electrospray ionization Fourier‐transform ion‐cyclotron‐resonance (ESI‐FTICR) mass spectrometry and in solution by 1H NMR titration studies. The electronic nature of the substituents on the upper rim of the resorcinarene was directly reflected in the order of binding strengths of the hosts towards quaternary and diquaternary ammonium cations in the gas phase. In solution, the opposite trend was observed, with generally higher binding constants for the diquaternary over the quaternary salts. This phenomenon is explained by the synergetic effect originating from the interaction of the halogenated resorcinarenes with the counteranions through enhanced hydrogen bonding, leading to ion‐pair binding in solution. The electronegativity of the halogens renders the hydrogen of the hydroxy group more acidic, and hence enforces hydrogen bonding in solution. The collective effect of several weak interactions is manifested in solution, thereby emphasizing the benefits of comparing solution and gas‐phase studies in recognition processes.

Bis(Diquaternary Ammonium)Salts: Synthesis, Effect of Spacer on Surface Activities and Aggregation Properties of Reactive Red 198 in Aqueous – Surfactants Solutions

Abstract A series of bis-diquaternary ammonium salts (cationic Gemini surfactants) with different length in spacer were prepared and characterized. The surface properties such as the critical micelle concentration CMC, minimum surface tension γCMC, effectiveness of the surface tension reduction πCMC, maximum surface excess Γmax and surface area per molecule Amin have been determined by means of surface tension measurements. As expected, these surfactants have good surface activities than those conventional monomeric ones (dodecyl trimethyl ammonium chloride (DTAC)) and the spacer plays an important role in the surface properties. Under experimental conditions, surface parameters decreases with the increase of carbon number of the spacer the except analogue with a benzene ring due to its inflexibility. The aggregation ability of some practically used reactive azodyes (C.I. Reactive Red 198) in aqueous solutions and the prepared surfactants was investigated using UV-visible spectroscopic methods. The spectroscopic studies were extended in order to determine the effect of molecular structure of the surfactants on the aggregative properties of C.I. Reactive Red 198 (RR 198). The aggregation behaviour of the RR 198 in solutions and in the presence of additives is related to their apparent deviations from Beer's law and aggregation number (N). The aggregation constant (Kn) of the monomer/dimer equilibrium was calculated. The aggregate structures and the nature of the interacting pairs in this dye were discussed using Kasha exciton theory.

Synthesis and Structure‐Activity Relationship of Di‐(3, 8‐diazabicyclo[3.2.1]octane) Diquaternary Ammonium Salts as Unique Analgesics

Based on the structure characteristics of the lead compounds, 1, 1' octanedioyl-4, 4'-dimethyl-4, 4'-dibenzyl dipiperazinium dibromide (2) and 3, 8-disubstituted-3, 8-diazabicyclo [3.2.1]octanes (DBO), di-(3, 8-diazabicyclo [3.2.1]octane) diquaternary ammonium salts 3 a-c were designed and synthesized through a highly practical procedure. Target compounds 3 a-c and the hydrochloride salts of their precursors 10 a-c were evaluated for their in vivo analgesic and sedative activities. Interestingly, the introduction of an endoethylenic bridge in the piperazine of lead compound 2 causes loss of the analgesic activity and increases the toxicity dramatically. This result shows that the flexible conformation of piperazine in compound 2 is favorable for interaction with the receptor, and the quaternization of compounds 10 a-c is the main reason for the toxicity increase.

Diquaternary ammonium compounds as transfection agents.

Diquaternary ammonium salts constitute a new class of reagent for mediating transfection of DNA in mammalian cell lines. N,N'-dioleyl-N,N,N',N'-tetramethyl-1,2-ethanediamine (TmedEce), N,N'-dioleyl-N,N,N',N'-tetramethyl-1,3-propanediamine (PropEce), N,N'-dioleyl-N,N,N',N'-tetramethyl-1,6-hexanediamine (HexEce), and their corresponding N,N'-dicetyl saturated analogues (TmedAce, PropAce and HexAce) have all been synthesized and characterized. They were prepared via a bis-Menshutkin reaction of the corresponding tetramethyldiamine with 2.2 M equiv of a long-chain alkyl halide (saturated or unsaturated). The reaction was run in anhydrous acetonitrile for ca. 3 days at 60 degrees C, which produced the diquaternary ammonium halides in good to nearly quantitative yields for most derivatives. DNA transfection comparable to commercially available reagents such as Lipofectin, Lipofectace, Lipofectamine, and O-ethyldioleoylphosphatidylcholinium triflate has been achieved in vitro with these new reagents. There was no need to use a colipid for effective transfection, but serum did significantly inhibit transfection. The saturated and the unsaturated derivatives differed with respect to hydration behavior. The saturated derivatives appeared to retain a lamellar-type crystalline array structure upon hydration, whereas the unsaturated versions formed micelles and/or liposomes, depending on the ionic strength: HexEce was micellar in both water and saline; PropEce was micellar in water but lamellar in saline; and TmedEce was lamellar in both. Despite these different hydration patterns, all of these unsaturated derivatives formed productive transfection complexes with DNA. Varying the distance between the quaternary sites affected transfection efficacy in the order HexAce > TmedAce = PropAce for the saturated derivatives and in the order PropEce = HexEce > TmedEce, with a smaller spread, for the unsaturated derivatives.

ChemInform Abstract: Synthesis and Biological Activities of Dibenzyl Dipiperazine Diquaternary Ammonium Salts.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis and Biological Activities of Dibenzyl Dipiperazine Diquaternary Ammonium Salts

Twenty new 4,4′-dibenzoyl-1,1′-dibenzyl-1,1′-(decane-1,5-diyl)-piperazinium dihalides 5a-l and 1,1prime;-dibenzyl-1,1′-(decane-1,5-diyl) piperazinium dihydrochloride dihalides 6a-l were prepared and evaluated for their analgesic, sedative and anti-inflammatory activities. Structure-activity relationship studies indicated that the compounds 6c (Ar = 4-NO2C6H5) and 6k (Ar = 3-Me-C6H5) exhibited higher activities than others. Compared with the corresponding compounds 6k and 6l, the presence of benzoyl in the compound 5k and 5l exerted a contrary influence on the activities. 5h and 6h show the highest anti-inflammatory activity (59%, dose 20 mg/kg and 48%, dose 1 mg/kg) in the series 5 and 6, respectively.

Synthesis and biological activities of dibenzyl dipiperazine diquaternary ammonium salts.

Twenty new 4,4'-dibenzoyl-1,1'-dibenzyl-1,1'-(decane-1,5-diyl)-piperazi nium dihalides 5a-l and 1,1'-dibenzyl-1,1'-(decane-1,5-diyl)piperazinium dihydrochloride dihalides 6a-l were prepared and evaluated for their analgesic, sedative and anti-inflammatory activities. Structure-activity relationship studies indicated that the compounds 6c (Ar = 4-NO2C6H5) and 6k (Ar = 3-Me-C6H5) exhibited higher activities than others. Compared with the corresponding compounds 6k and 6l, the presence of benzoyl in the compound 5k and 5l exerted a contrary influence on the activities. 5h and 6h show the highest anti-inflammatory activity (59%, dose 20 mg/kg and 48%, dose 1 mg/kg) in the series 5 and 6, respectively.

Effects of solvent and counterion on ion pairing and observed charge states of diquaternary ammonium salts in electrospray ionization mass spectrometry

Two diquaternary ammonium chloride salts have been used to examine the roles of solvent and counterion in determination of the degree of ion pairing in solution and the resultant charge state distributions in electrospray ionization mass spectrometry (ESI-MS). Three series of solvents, that is, alcohol, polar aprotic, and chlorinated solvents, have been employed to test the influence of solvent polarity and other parameters on the desorption behavior of diquaternary ammonium ions observed in ESI-MS. Solvents of higher polarity were found to yield gas-phase ions of higher charge states, in accordance with their reduced tendency toward ion pairing in solution. Counterion effects were investigated via the following approaches: (1) increase the diquaternary ammonium salt concentration; (2) increase the concentration of an external electrolyte that contained the common counterion Cl(-); (3) replace Cl(-) with trifluoroacetate (TFAc (-)); (4) increase the concentration of an external electrolyte that contained TFAc(-). These experiments indicate that variation of the specific counterion employed alters the degree of influence that the counterion exerts (via ion pairing) on electrospray ionization mass spectra. Increasing amounts of trifluoroacetate ions in a variety of solvent systems invariably led to a progressive shift of the observed ESI-MS charge states of diquaternary ammonium ions toward lower values.

Diamine and Diammonium Extractants

The application of di-tertiary amines and di-quaternary ammonium salts as extractants for metal ion separation is discussed. The versatility of the di-tertiary amines is illustrated. In these cases, two extraction mechanisms are postulated to coincide with the low and high pH conditions employed in the aqueous phases. The advantages in applying these two mechanisms for the selective extraction of metals from, and stripping to aqueous media are outlined. The potential advantages of these reagents over monoamines are discussed. Other features unique to diamine/diammonium extractants, e.g., differences in “acid effects” associated with these extractants, their differing tendencies towards third phase formation, etc., will be illustrated with extraction isotherms.

Polymeric membrane anion-selective electrodes based on diquaternary ammonium salts

Polymeric membrane anion-selective electrodes based on diquaternary ammonium salts

Micellization and surface activity of long-chain monoquaternary and diquaternary ammonium salts

Six monoquaternary ammonium bromide amphiphiles (CH/N⊕, − 20 1 and nine diquaternary ammonium species (bola amphiphiles) (CH/N⊕, 11 1 and 16 1 ) have been synthesized. The critical micelle concentration of each has been determined using equilibrium surface tension and equivalent conductivity data. Water-air interface parameters have also been derived from the surface tension data using the Gibbs adsorption isotherm. The monoquaternary ammonium salts behave more or less like conventional surfactants. However, each contains an ester group in its long chain and this appears to be located via a “loop-like” conformation at both the micelle and the water—air interfaces. The diquaternary ammonium salts also display aggregation phenomena, with apparent CMC values below that expected for their CH/N ratio, but consistent with the overall large hydrocarbon structure of each. The terminal positions of the cationic groups seem likely to make packing into spherical micelles problematical, and the aggregates formed in this case might be lamellar in nature. The dye solubilization behavior is also consistent with such a structure. Both N⊕ centers in each bola species are located at each interface, again via a “loop-like” structure. Each also shows evidence for discrete ion-pair formation ⊝Br ⊕N fx245-1N ⊕ in the bulk solution below the CMC, and a second discontinuity in the surface tension data at concentrations far below the CMC. The latter appears to be due to the binding of ester groups in the hydrocarbon skeleton at the interface, via “multiple loops.” Salts bearing a methacryloxyethyl substituent directly on N ⊕ show evidence for this being intramolecularly associated with N ⊕ in the micellar interface.

Studies with a laboratory-constructed thermospray liquid chromatograph-mass spectrometer interface

The influence of a series of “thermospray electrolytes” (ammonium acetate, chloride, bromide and iodide and potassium acetate) on the characteristic mass spectra of saccharides diquaternary ammonium salts was investigated with a laboratory-constructed thermospray (TSP) liquid chromatograph-mass spectrometer interface. The observed dependence of mass spectral fragmentation and total ion current on the concentration and thermal stability, or temperature of volatilization, of TSP electrolytes indicates a significant role for solid particles in TSP ionization. The observed fragmentation is suggested to be related to the formation and decomposition of solid particles and to ion chemistry in the desolvation of molecules rather than to a “purely” thermal effect. A strong influence of the thermospray operating temperature on the relative fragment ion intensities could only be observed for diazo dyes.