Alkylation Of Anion Research Articles

Sulfonium closo-hydridodecaborate anions as active components of a potentiometric membrane sensor for lidocaine hydrochloride

A method for the preparation of sulfonium derivatives of the closo-hydridodecaborate anion [B10H9SR2]− with exo-polyhedral alkyl groups (R = i-Pr, n-Pr, n-Bu, n-C8H17, n-C12H25, n-C18H37) has been developed. A procedure for the preparation of mono-S-substituted derivatives of the closo-hydridodecaborate anion by the interaction between the [B10H9SH]2− anion and secondary alkyl halides has been developed. This paper presents the results of studies on the use of the sulfonium derivative of the closo-hydridodecaborate anion [B10H9S(C18H37)2]− as the active component of a hybrid polymer membrane designed to create a potentiometric lidocaine-selective sensor. The optimal composition of the proposed membrane composition has been found. The electroanalytical characteristics of the manufactured potentiometric sensor have been determined; the detection limit of lidocaine has been found to be 3.5 • 10−8 M.

Separation and determination of alkyl sulfate surfactants in wastewater by capillary electrophoresis coupled with contactless conductivity detection after preconcentration by simultaneous adsorption using alumina beads

The aim of the present study is to determine four anionic alkyl sulfate (AS) surfactants with different alkyl chains, namely, C8, C10, C12, and C14, in wastewater by CE with capacitively coupled contactless conductivity detection (CE-C4 D). The conditions effective for the separation of the four AS surfactants were systematically optimized and found to be in a Tris-His (50mM/20mM) BGE solution at a pH of 8.95, using a separation voltage of +15kV, hydrodynamic injection by siphoning using a 20cm injection height and an injection time of 20 s. The LODs for C8, C10, C12, and C14 were 2.58, 2.30, 2.08, and 3.16mg/L, respectively. The conditions used to achieve the simultaneous adsorption and preconcentration of the AS surfactants using Al2 O3 beads were pH of 3 and 0.1mM NaCl. The adsorption efficiencies were found to be 45.6, 50.8, 81.7, and 99.9%, while the desorption efficiencies reached 66.1, 70.4, 83.9, and 100.0% for C8, C10, C12, and C14, respectively. The concentrations of the AS surfactants in wastewater samples were quantified by CE-C4 D after preconcentration by simultaneous adsorption using Al2 O3 beads. The results obtained from the proposed method were consistent with those obtained by HPLC-MS/MS, with a deviation of less than 15%. Our results indicate that the CE-C4 D performed after preconcentration by an adsorption technique using Al2 O3 beads is a new, inexpensive, and suitable method for quantifying AS surfactants in wastewater samples.

Study of the toluene absorption capacity and mechanism of ionic liquids using COSMO-RS prediction and experimental verification

As green solvents, ionic liquids (ILs) are quite suitable for the absorption of volatile organic compounds (VOCs) such as benzene and its homologues. However, solvent selection is the key to the VOC absorption process. In the present study, a rapid solvent screening tool, Conductor-like Screening Model for Real Solvents (COSMO-RS), was used to predict the solubility of toluene in 816 ILs. The effects of four structure characters, namely, the type and alkyl chain length of the cations and anions on the solubility of toluene were discussed. The following conclusions were drawn from the results: (1) ILs with pyrrolidinium-based cations showed better solubility than pyridinium- and imidazolium-based ones. (2) The solubility of toluene in PF6-based ILs increased with the increasing alkyl chain length, while its solubility in Ac-based ILs exhibited the opposite trend. (3) Toluene showed greater solubility in Cl-based ILs than those based on other anions. (4) The solubility of toluene increased with the anion alkyl chain length. Ac-based ILs were chosen as the most promising potential solvents, and further studied to determine the relationship between various interaction energy parameters and toluene solubility. The results showed that the misfit energy played a dominant role during the absorption process. Furthermore, several ILs were selected for experimental verification of the predicted solubility behavior using liquid and gaseous toluene. The results demonstrated that COSMO-RS could be used to semi-quantitatively and qualitatively predict the solubility of toluene, and this model had promising prospects in screening ILs for VOCs absorption. In summary, this study provided a fundamental basis and practical data for the control and treatment of VOCs.

Direct Micromolding of Bimetals and Transparent Conducting Oxide Using Metal-TOABr Complexes as Single-Source Precursors.

Patterning of metals, alloys, and conducting oxides is vitally important for many industrial applications pertaining to many technological devices. In this report, we have used the metal anion alkyl ammonium complex (M–TOABr) as a single-source precursor to obtain thin films as well as micro (μ)-patterns of bimetals (Au–Pd, Au–Pt, Au–Cu, and Pt–Pd) and conducting oxides (ITO). This complex can be easily filled inside the soft mold and converted to the desired material in a single step known as direct patterning. The as-obtained μ-pattern comprises a well-connected network of nanocrystals giving rise to metallic conductivity. These periodically aligned bimetals and transparent conducting oxide (TCO) microwires could effectively serve as electrodes as well as an electrocatalyst with the prudence of providing passage for light transmission for many functional photoelectrochemical devices. In addition, the electrochemical stability of the bimetallic film was examined by fabricating a supercapacitor device and by studying its performance.

Evaluation of the Photosonolysis Process Efficacy for the Removal of Anionic Surfactant Linear Alkyl Benzene Sulfonate from Aqueous Solutions

In this study, the experiments on the sulfonate linear alkylbenzene (LAS) solution were performed using the methylene blue active substances (MBAS) method. The effectiveness of the sonochemical and photochemical reactors for LAS degradation was evaluated with an emphasis on the effect of the contact time, pH values, type of process and initial concentrations. The experiments were carried out at the initial concentrations of 0.5 mg/L, 14.00 mg/L and 21.00 mg/L, the contact time of 8, 16, and 24 minutes, pH of 3, 7, and 11, the ultrasonic frequency of 42 kHz, the acoustic power value of 160 W, an ultraviolet lamp with 150W power and the wavelength of 254 nm. This study showed that the LAS degradation was increased along with the contact time. In addition, at alkaline pH, the removal efficiency increased as well. Overall, the results obtained from this research demonstrated that by themselves, both the sonochemical and photochemical reactors may not be useful for completely reducing the complex wastewaters with high surfactant loads, but the succession of the UV/US process has a significant effect on the removal of anionic detergents. These findings demonstrated the removal efficiency under alkaline conditions and the contact time of 24 minutes was equal to 96.97 percent.

Chitin-glucan complex – Based biopolymeric structures using biocompatible ionic liquids

This work explores the novelty of dissolving chitin-glucan complex (CGC), from two fungal strains, Komagataella pastoris (CGCP) and Aspergillus niger (CGCKZ) (KiOnutrime-CG™), using biocompatible ionic liquids (ILs). Three cholinium-based ILs were tested, choline acetate, choline propionate and choline hexanoate. Although all tested ILs resulted in the dissolution of the co-polymer at a concentration of 5 % (w/w), distinct polymeric structures, films or gels, were obtained from CGCP and CGCKZ, respectively. CGCP films were dense, flexible and elastic, with high swelling capacity (> 200 %). The IL anion alkyl chain length influenced the polymeric structures’ properties, namely, the CGCP films elongation at break and swelling degree. CGCKZ resulted in weak gels. For both polymeric structures, exposure to the ILs under the dissolution conditions caused significant changes in the co-polymers’ chemical structure, namely, reduction of their glucan moiety and reduction of the degree of acetylation, thus yielding chitosan-glucan complexes (ChGC) enriched in glucosamine (53.4 ± 0.3–60.8 ± 0.3 %).

Tertiary Alkylations of Aldehydes, Ketones or Imines Using Benzylic Organoboronates and a Base Catalyst

Abstract The KHMDS-catalyzed tertiary alkylation of aldehydes, ketones or imines using tertiary benzylic organoboronates is reported. This protocol permitted the use of tertiary benzylic alkylboronates as the tertiary alkyl anion for construction of highly congested contiguous sp3 carbon centers. The mild and transition-metal-free reaction conditions are attractive features of the protocol.

Designing silica xerogels containing RTIL for CO2 capture and CO2/CH4 separation: Influence of ILs anion, cation and cation side alkyl chain length and ramification

CO2 separation from natural gas is considered to be a crucial strategy to mitigate global warming problems, meet product specification, pipeline specs and other application specific requirements. Silica xerogels (SX) are considered to be potential materials for CO2 capture due to their high specific surface area. Thus, a series of silica xerogels functionalized with imidazolium, phosphonium, ammonium and pyridinium-based room-temperature ionic liquids (RTILs) were synthesized. The synthesized silica xerogels were characterized by NMR, helium pycnometry, DTA-TG, BET, SEM and TEM. CO2 sorption, reusability and CO2/CH4 selectivity were assessed by the pressure-decay technique. Silica xerogels containing IL demonstrated advantages compared to RTILs used as separation solvents in CO2 capture processes including higher CO2 sorption capacity and faster sorption/desorption. Using fluorinated anion for functionalization of silica xerogels leads to a higher affinity for CO2 over CH4. The best performance was obtained by SX- [bmim] [TF2N] (223.4 mg CO2/g mg/g at 298.15 K and 20 bar). Moreover, SX- [bmim] [TF2N] showed higher CO2 sorption capacity as compared to other reported sorbents. CO2 sorption and CO2/CH4 selectivity results were submitted to an analysis of variance and the means compared using Tukey's test (5%).

Scalable Synthesis of Esp and Rhodium(II) Carboxylates from Acetylacetone and RhCl3·xH2O.

Rhodium(II) carboxylates are privileged catalysts for the most challenging carbene-, nitrene-, and oxo-transfer reactions. In this work, we address the strategic challenges of current organic and inorganic synthesis methods to access these rhodium(II) complexes through an oxidative rearrangement strategy and a reductive ligation reaction. These studies illustrate the multiple benefits of oxidative rearrangement in the process-scale synthesis of congested carboxylates over nitrile anion alkylation reactions, and the impressive effect of inorganic additives in the reductive ligation of rhodium(III) salts.

Ultra-low interfacial tension biobased and catanionic surfactants for low permeability reservoirs

Abstract Alkyl polyglucoside, an eco-friendly, stable and low-cost available biobased surfactant, was chemically modified to develop ultra-low interfacial tension (IFT) surfactants for crude oil recovery from low permeability reservoirs. The modified anionic surfactant alkyl polyglucoside sodium hydroxypropyl sulfonate (APGSHS) was structurally characterized by FT-IR, 1H NMR and TGA methods. Following that, the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) was combined with APGSHS to formulate the ultra-low oil/water IFT catanionic surfactants, which exhibits higher water-solubility than DTAB/APGSHS mixtures at various concentrations and combined ratios. Furthermore, the surface properties, thermodynamic parameters of the sole and combined surfactants show that the combined APGSHS/CTAB catanionic surfactants have lower surface tension (22.90 mN/m) at cmc, smaller area occupied per molecule and stronger micellization capacity, which indicates that the surfactant molecules are tightly absorbed onto the two-phase interface for catanionic surfactants. The mechanism underlying the strong electrostatic attraction between the ion head groups in APGSHS and CTAB could be proven by the high absolute value of interaction parameters (12.23) in binary systems. Besides, the salinity resistance effect tests indicate that the ultra-low IFT formula exhibits excellent performance in both monovalent and divalent ions conditions. Notably, the APGSHS/CTAB surfactants with total concentration of 3000 mg/L and molar ratio of 6:4 can effectively enhance oil recovery and decrease the injected pressure for low permeability reservoirs. Hence, the newly formulated green catanionic surfactants exhibit remarkable abilities for maintaining the ultra-low IFTs and can be used for EOR in low permeability and high salinity reservoirs.

Two fatty acid anion-based ionic liquids - part I: Physicochemical properties and tribological behavior as neat lubricants

Two new ionic liquids ([N 6,6,6,6 ][C 8:0 ] and [N 6,6,6,6 ][C 16:0 ]) synthetized from fatty acids through a salt metathesis reaction were both characterized from a physicochemical and tribological point of view. Density, viscosity, corrosion activity and thermal stability tests were performed before making tribological tests under ball-on-disc both unidirectional (with fixed and variable slide-to-roll ratio) and reciprocating configuration. The main results of this work were the following: the longer the length of the alkyl chain of the anion the lower both viscosity and density and higher both viscosity index and thermal stability; these ionic liquids (ILs) are not corrosive; the [N 6,6,6,6 ][C 16:0 ] behaved better changing from elastohydrodynamic to mixed lubrication regime at lower speeds; their antiwear behavior at high load seems depend on their viscosity (for tests made at room temperature) and thermal stability and IL-surface interaction (for tests made at high temperature). • Two fatty acids anion-based ionic liquids were obtained and tribologically studied. • These fatty acids anion-based ionic liquids are not corrosive. • The anion alkyl chain length determines viscosity, thermal and tribological behavior.

Genome-wide identification for genes involved in sodium dodecyl sulfate toxicity in Saccharomyces cerevisiae

BackgroundSodium dodecyl sulfate (SDS) is one of the most widely used anionic alkyl sulfate surfactants. Toxicological information on SDS is accumulating, however, mechanisms of SDS toxicity regulation remain poorly understood. In this study, the relationship between the SDS-sensitive mutants and their intracellular ROS levels has been investigated.ResultsThrough a genome-scale screen, we have identified 108 yeast single-gene deletion mutants that are sensitive to 0.03% SDS. These genes were predominantly related to the cellular processes of metabolism, cell cycle and DNA processing, cellular transport, transport facilities and transport routes, transcription and the protein with binding function or cofactor requirement (structural or catalytic). Measurement of the intracellular ROS (reactive oxygen species) levels of these SDS-sensitive mutants showed that about 79% of SDS-sensitive mutants accumulated significantly higher intracellular ROS levels than the wild-type cells under SDS stress. Moreover, SDS could generate oxidative damage and up-regulate several antioxidant defenses genes, and some of the SDS-sensitive genes were involved in this process.ConclusionThis study provides insight on yeast genes involved in SDS tolerance and the elevated intracellular ROS caused by SDS stress, which is a potential way to understand the detoxification mechanisms of SDS by yeast cells.

Enhancing the Biocatalytic Activity of l-Asparaginase Using Aqueous Solutions of Cholinium-Based Ionic Liquids

L-asparaginase (ASNase) is a high value enzyme for the pharmaceutical and food industries. Although ionic liquids (ILs) have been recognized as promising solvents or additives for biocatalysis, there are very few studies on the effect of ILs on the activation of ASNase. To address this, the enzymatic activity of a commercial ASNase in aqueous ILs was evaluated. ASNase was exposed for up to 24 h to aqueous solutions (0.001-0.050 mol.mol-1) of cholinium ([Ch])-based ILs, at three temperatures (25, 37 and 50 °C). At 25 oC, [Ch]-based ILs aqueous solutions enhanced the biocatalytic activity of ASNase, with a maximum increase of the relative ASNase activity (in ca. 250%) achieved by adding cholinium chloride ([Ch]Cl). Spectroscopic and calorimetric analysis were performed to understand the effect of [Ch]Cl on the ASNase structure, but no significant changes were observed. Although all [Ch]-based ILs enhanced the relative ASNase activity, the positive effects were diminished with increasing the anion alkyl chai...

Liquid–Liquid Equilibrium and Extraction Performance of Aqueous Biphasic Systems Composed of Water, Cholinium Carboxylate Ionic Liquids and K2CO3

Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have been broadly investigated for the separation of high-value compounds. Nevertheless, the large-scale application of IL-based ABS is still hampered by the high cost and hazardous features of most ILs used. Aiming at characterizing novel ABS composed of ILs with a more acceptable environmental footprint and enhanced biocompatibility, in this work, ABS formed by water, cholinium carboxylate ILs ([Ch][CnCO2], with n = 2 to 6), and K2CO3 were investigated. The respective ternary phase diagrams, including binodal curves, tie-lines, and critical points, were determined at (298 ± 1) K and atmospheric pressure. The capability to form ABS (or of the IL to be salted-out) increased with the increase of the alkyl chain length of the IL anion up to cholinium pentanoate; however, for longer anion alkyl chain lengths the ILs self-aggregation led to a decrease of the ILs ability to form ABS. Furthermore, the liquid–liquid equilibrium data experimentally determ...

Synthesis of the ABCD fragment of gymnocin-B

A convergent synthesis of the ABCD fragment of gymnocin-B was accomplished. The tetracyclic ether ring system was synthesized by the construction of the BC ring system via the oxiranyl anion alkylation and ring expansion reaction, followed by the formation of the five-membered A-ring via a stereoselective radical cyclization reaction of a neopentyl-type iodide.

Remote-controlled nucleophilicity III: A valuable model to explain and predict the observed regioselectivity of the electrophilic attack on substituted 4-methylpyridine anions

In a comparative study, the stability of lithiated methylpyridine and the reactivity of side chain functionalized 4-methylypridines were investigated. In contrast to gas phase calculations, the observed N-coordination of the lithium to 4-methylpyridine anions is shown to be a solvent effect. Furthermore, lithiated methylpyridines are predicted to be dimeric in THF.The regioselectivity of the picoline anion alkylation was subject to an in-depth study. The activation barriers for the methylation of methylpyridine in Cα, C(3), and N position were determined and compared with partial NPA charges in an attempt to explain the observed selectivity. While there is no correlation of the charges with the selectivity, the calculated activation energies not only fit well with experimental conditions but also parallel the predominantly observed regioselectivity of alkylation at the exocyclic carbon atom. In agreement with the experiment no attack at the C(3) is observed. In case of a Cα and N methylation mixture (for the 4-(phenyl(tosyl)methylpyridine), the activation barrier difference between the two pathways diminishes to almost 0 kcal/mol.

Design of Ionic Liquid Crystals Forming Normal-Type Bicontinuous Cubic Phases with a 3D Continuous Ion Conductive Pathway

We have prepared a series of pyridinium-based gemini amphiphiles. They exhibit thermotropic liquid–crystalline behavior depending on their alkyl chain lengths and anion species. By adjusting the alkyl chain lengths and selecting suitable anions, we have obtained an ionic amphiphile that exhibits a normal-type bicontinuous cubic phase from 38 °C to 12 °C on cooling from an isotropic phase. In the bicontinuous cubic liquid–crystalline assembly, the pyridinium-based ionic parts align along a gyroid minimal surface forming a 3D continuous ionic domain while their ionophobic alkyl chains form 3D branched nanochannel networks. This ionic compound can form homogeneous mixtures with a lithium salt and the resultant mixtures keep the ability to form normal-type bicontinuous cubic phases. Ion conduction measurements have been performed for the mixtures on cooling. It has been revealed that the formation of the 3D branched ionophobic nanochannels does not disturb the ion conduction behavior in the ionic domain while it results in the conversion of the state of the mixtures from fluidic liquids to quasi-solids, namely highly viscous liquid crystals. Although the ionic conductivity of the mixtures is in the order of 10–7 S cm–1 at 40 °C, which is far lower than the values for practical use, the present material design has a potential to pave the way for developing advanced solid electrolytes consisting of two task-specific nanosegregated domains: One is an ionic liquid nano-domain with a 3D continuity for high ionic conductivity and the other is ionophobic nanochannel network domains for high mechanical strength.

Effects of cholinium-based ionic liquids on Aspergillus niger lipase: Stabilizers or inhibitors.

Lipases are well-known biocatalysts used in several industrial processes/applications. Thus, as with other enzymes, changes in their surrounding environment and/or their thermodynamic parameters can induce structural changes that can increase, decrease, or even inhibit their catalytic activity. The use of ionic compounds as solvents or additives is a common approach for adjusting reaction conditions and, consequently, for controlling the biocatalytic activity of enzymes. Herein, to elucidate the effects of ionic compounds on the structure of lipase, the stability and enzymatic activity of lipase from Aspergillus niger in aqueous solutions (at 0.05, 0.10, 0.50, and 1.00 M) of six cholinium-based ionic liquids (cholinium chloride [Ch]Cl; cholinium acetate ([Ch][Ac]); cholinium propanoate ([Ch][Prop]); cholinium butanoate ([Ch][But]); cholinium pentanoate ([Ch][Pent]); and cholinium hexanoate ([Ch][Hex])) were evaluated over 24 hr. The enzymatic activity of lipase was maintained or enhanced in the lower concentrations of all the [Ch]+ -ILs (below 0.1 M). [Ch][Ac] maintained the biocatalytic behavior of lipase, independent of the IL concentration and incubation time. However, above 0.1 M, [Ch][Pent] and [Ch][Hex] caused complete inhibition of the catalytic activity of the enzyme, demonstrating that the increase in the anionic alkyl chain length strongly affected the conformation of the lipase. The hydrophobicity and concentration of the [Ch]+ -ILs play an important role in the enzyme activity, and these parameters can be controlled by adjusting the anionic alkyl chain length. The inhibitory effects of [Ch][Pent] and [Ch][Hex] may be of great interest to the pharmaceutical industry to induce pharmacological inhibition of gastric and pancreatic lipases.

Application of the Hydrophilic–Lipophilic Deviation Concept to Surfactant Characterization and Surfactant Selection for Enhanced Oil Recovery

AbstractThe hydrophilic–lipophilic deviation (HLD) concept has been demonstrated to be useful in determining characteristic curvature (Cc) of a surfactant. Cc is a surfactant parameter that reflects the hydrophobicity/hydrophilicity or the tendency of the surfactant to form microemulsions in an oil–water system. In order for the Cc value to be calculated, the formation of the optimum Winsor III microemulsion of oil and water systems under specific salinity and temperature conditions is required. Surfactant Cc values have been widely used to quantitatively screen and select a suitable surfactant in formulations for different application areas, especially enhanced oil recovery (EOR). The HLD concept is an effective tool for designing new surfactant molecules to meet the target Cc value for a specific formulation condition. The HLD equation indicates the dependence of a microemulsion system on the changes of various system parameters. This article demonstrates how the HLD equation can be derived in different ways depending on the characteristics of the surfactant to identify the proper experimental approach so that the Cc values of different types of surfactants can be determined. Three types of surfactants were studied, including nonionic alcohol ethoxylates, anionic alkyl propoxy ethoxy sulfates, and carboxylates. The application of the HLD concept to surfactant selection for EOR application was also demonstrated.

Origins and applications of stereoselective sulfenate anion alkylation reactions

Selected sulfenate anions can be alkylated with diastereoselectivities near 9:1 when there is appropriately positioned carbon chirality in the sulfenate structure or in the alkylation electrophile. Both protocols represent a conceptually different approach to β-amino sulfoxides. When vinylic β-amino sulfoxides are cyclized, thiomorpholine S-oxides result, and substrate control over the stereochemistry of alkyl substituents was found. This finding facilitates the synthesis of cis and trans dialkylpyrrolidines, known ant venom alkaloids. A computational model is demonstrated to account for some of the diastereoselection results. The importance of intramolecular interactions of sulfenate constituent atoms with pendent substituents is established.