Octyl Ammonium Research Articles

Investigation of synthesis of some ionic liquids from nitrogen compounds and fatty acids of waste oils

In order to reduce the environmental pollution and the dependence on fossil fuel resource which is depleting, the utilization of waste vegetable oils for preparation of valuable products are of concern. Four ionic liquids triethyl ammonium carboxylate ([TEA][WO]), octyl ammonium carboxylate ([OcA][WO]), trialkyl methyl ammonium carboxylate ([Aliquat][WO]) and n-octyl methyl imidazolium carboxylate ([OMIM][WO]) were synthesized from four different nitrogen compounds and fatty acids of waste vegetable oils. The influence of some parameters such as solvent, reaction temperature, reaction time and molar ratio of acid and nitrogen compound (NC) on ionic liquid synthesis yields was investigated. The results show that the structure of nitrogen compounds effects on the synthesis performance and governs the parameters of processes. This is due to the nitrogen compounds as starting materials control not only their activity in reaction with fatty acids but also the solubility and the melting points of corresponding ionic liquids. Certain suitable conditions were chosen for each ionic liquid.

Antimicrobial Hydrogels Based on Cationic Curdlan Derivatives for Biomedical Applications.

Hydrogels based on biocompatible polysaccharides with biological activity that can slowly release an active principle at the wound site represent promising alternatives to traditional wound dressing materials. In this respect, new hydrogels based on curdlan derivative with 2-hydroxypropyl dimethyl octyl ammonium groups (QCurd) and native curdlan (Curd) were obtained at room temperature by covalent cross-linking using a diepoxy cross-linking agent. The chemical structure of the QCurd/Curd hydrogels was investigated by Fourier transform infrared spectroscopy (FTIR) spectroscopy. Scanning electron microscopy (SEM) revealed well-defined regulated pores with an average diameter between 50 and 75 μm, and hydrophobic micro-domains of about 5 μm on the pore walls. The high swelling rate (21-24 gwater/ghydrogel) and low elastic modulus values (7-14 kPa) make them ideal for medical applications as wound dressings. To evaluate the possible use of the curdlan-based hydrogels as active dressings, the loading capacity and release kinetics of diclofenac, taken as a model drug, were studied under simulated physiological skin conditions. Several mathematical models have been applied to evaluate drug transport processes and to calculate the diffusion coefficients. The prepared QCurd/Curd hydrogels were found to have good antibacterial properties, showing a bacteriostatic effect after 48 h against S. aureus, MRSA, E. coli, and P. aeruginosa. The retarded drug delivery and antimicrobial properties of the new hydrogels support our hypothesis that they are candidates for the manufacture of wound dressings.

Synergistic Effect of Precursor and Interface Engineering Enables High Efficiencies in FAPbI3 Perovskite Solar Cells.

Formamidinium lead iodide (FAPbI3)-based perovskite solar cells have gained immense popularity over the last few years within the perovskite research community due to their incredible opto-electronic properties and the record power conversion efficiencies (PCEs) achieved by the solar cells. However, FAPbI3 is vulnerable to phase transitions even at room temperature, which cause structural instability and eventual device failure during operation. We performed post-treatment of the FAPbI3 surface with octyl ammonium iodide (OAI) in order to stabilize the active phase and preserve the crystal structure of FAPbI3. The formation of a 2D perovskite at the interface depends on the stoichiometry of the precursor. By optimizing the precursor stoichiometry and the concentration of OAI, we observe a synergistic effect, which results in improved power conversion efficiencies, reaching the best values of 22% on a glass substrate. Using physical and detailed optical analysis, we verify the presence of the 2D layer on the top of the 3D surface of the perovskite film.

Mixing Dion–Jacobson and Ruddlesden–Popper Structures in Quasi‐2D Perovskite Films for Thermal‐ and Photo‐Stable Stimulated Emission

AbstractQuasi‐two–dimensional (2D) perovskite films are promising candidates as a gain medium for stimulated emission owing to their hydrophobicity and efficient energy funneling that facilitates the population inversion. However, the commonly used Ruddlesden–Popper (R–P) perovskites still suffer from instability induced by high‐density pumping as well as the resulting heating effect. Here, quasi‐2D perovskite films with mixed Dion–Jacobson (D–J) and R–P phases are demonstrated with both excellent amplified spontaneous emission (ASE) properties and thermal‐ and photo‐stabilities under ambient conditions. In these films, octyl ammonium bulky organic cations are used to obtain the preferred crystal orientation and highly smooth surface for low‐threshold ASE, while 1,8‐octanedi ammonium cations contribute to the greatly improved stability. The films containing the D–J phase exhibit good structural stability even after 130 °C heat treatment for 48 h. The mixed‐ligands film maintains a low ASE threshold of 11.6 µJ cm−2 and a high optical gain of 413 cm−1 after environmental annealing. It is demonstrated that it is the diammonium that firmly bonds to the perovskite layer,allowing the maintenance of quasi‐2D perovskite structure and good ASE performances.

Organic Chain Length Effect on Trap States of Lead Halide Perovskite Scintillators

Scintillators fabricated from organic–inorganic layered perovskites have attracted wide attention due to their excellent properties, including fast decay times, superior light yield, and high exciton binding energy. In relation to their optoelectronic properties, hybrid organic–inorganic perovskites are known for their tunability, which could be manipulated by modifying the organic cations. In this study, we investigate the optical and scintillation properties of lead halide perovskites A2PbBr4, where A vary from amylammonium (AA), hexylammonium (HA), octylammonium (OA), and benzylammonium (BZA) organic ligands. Photoluminescence (PL) spectra display dual peaks due to surface and bulk trap states contributions, while fast average decay times from time-resolved photoluminescence (TRPL) for all samples are within the range of 0.69 ± 0.11–0.99 ± 0.13 ns. The optical band gap of these hybrid perovskites is within ∼3 eV range, which fulfill the criteria of promising scintillators. Radioluminescence (RL) spectra show negative thermal quenching behavior (NTQ) in all samples, with the AA2PbBr4 peak intensity appearing at relatively lower temperature compared to other samples. Thermoluminescence (TL) measurement reveals trap-free states in AA2PbBr4, while other samples possess shallow traps (<40 meV) as well as low trap density, which is beneficial for fast-decay scintillators, X-ray detection and energy conversion for solar cells. Overall, our results demonstrate that the extension of linear organic chains in lead-based perovskite is a deterministic strategy for a fast response hybrid-based scintillator to date.

Efficient and stable TiO2 nanorod array structured perovskite solar cells in air: Co-passivation and synergistic mechanism

In recent years, single crystal TiO2 nanorod arrays (TNRAs) with fewer grain boundaries for photo-generated electron transport and ordered channel structures for perovskite filling have been employed as electron transport layers for efficient perovskite solar cells (PSCs). However, further improvements in TNRA-based PSC performance are urgently needed because defects in the perovskite layer seriously hinder device efficiency and stability. In this study, with TNRAs as the electron transport layer, CH3NH3PbI3 (MAPbI3) perovskite films were prepared in air by a two-step spin coating method. The grain boundary defects and surface defects of the MAPbI3 layer are co-passivated by octyl ammonium iodide (CH3(CH2)7NH3I, OAI) and choline chloride (HOCH2CH2N(CH3)3Cl, Ch), respectively, and the effects of the two passive materials on the power conversion efficiency (PCE) and stability of TNRA-based PSCs are systematically investigated. The results reveal that the introduction of OAI facilitates the formation of intermolecular valence bonds between crystalline MAPbI3 to enhance its structural stability, while Ch passivates the Pb–I antisite substitution defect and I− vacancy defect on the perovskite film surface. Compared with the pristine device, the optimal PCE of the passivated device increases from 18.86% to 20.08%, and the thermal, humid and long-term stability of the device is also improved.

Precursor Tailoring Enables Alkylammonium Tin Halide Perovskite Phosphors for Solid‐State Lighting

AbstractBroadband emission with a large Stokes shift is of interest for applications in solid‐state lighting. Such emission is often achieved with self‐trapped excitons; however, in reduced‐dimensional perovskites, high‐performance self‐trapped emission has, until now, been widely observed only in lead‐based materials. Here, the synthesis in an air ambient of reduced‐dimensional Sn‐based perovskite phosphors R2 + xSnI4 + x [R = octylammonium (OTA), hexylammonium (HA) or butylammonium (BA)] is reported, an advance achieved by tailoring the synthesis of the Ruddlesden‐Popper 2D perovskites R2SnI4. The lead‐free R2 + xSnI4 + x phosphors have broadband self‐trapped emission with over 80% photoluminescence quantum yield (PLQY) and more than a 150 nm Stokes shift. White‐light‐emitting diodes (WLEDs) based on OTA2 + xSnI4 + x phosphors exhibit warm‐white emission (correlated color temperature = 2654K) suited to home lighting, and a CRI of 92, among the best for Pb‐free perovskite WLEDs reported to date.

VCD spectroscopy reveals conformational changes of chiral crown ethers upon complexation of potassium and ammonium cations.

Two chiral derivatives of 18-crown-6, namely the host molecules 2,3-diphenyl- and 2-phenyl-18c6, serve as model systems to investigate whether VCD spectroscopy can be used to monitor conformational changes occurring upon complexation of guests. Host-guest complexes of both crown ethers were prepared by addition of KNO3. The more bulky 2,3-diphenyl-18c6 is found to undergo major conformational changes upon encapsulation of K+, which are revealed as characteristic changes of the VCD spectral signatures. In contrast, while 2-phenyl-18c6 also incorporates K+ into the macrocycle, strong conformational changes are not occurring and thus spectral changes are negligible. With an octyl ammonium cation as guest molecule, 2,3-diphenyl-18c6 shows the same conformational and spectral changes that were observed for K+-complexes. In addition, the asymmetric NH3-deformation modes are found to gain VCD intensity through an induced VCD process. An analysis of the vibrational spectra enables a differentiation of VCD active and inactive guest modes: There appears to be a correlation between the symmetry of the vibrational mode and the induced VCD intensity. While this finding makes the host-guest complexes interesting systems for future theoretical studies on the origin of induced VCD signatures, the observations described in this study demonstrate that VCD spectroscopy is indeed a suitable technique for the characterization of supramolecular host-guest complexes.

Separation of vanadium and chromium in solution after vanadium precipitation by co-extraction with N263 and selective stripping with NaOH solution

The conventional process of extracting vanadium from vanadium slag produces a large amount of V-Cr-bearing residue (VCBR) and wastewater containing sulfate and ammonium salt. Through the research of the co-extraction and selective stripping of vanadium and chromium, this work proposes a novel process for extracting vanadium and chromium from vanadium slag to avoid the issues mentioned above. Methyl tri octyl ammonium carbonate (N263) can co-extract vanadium and chromium from solution after vanadium precipitation. Vanadium can be selectively stripped by NaOH solution from the loaded organic solution containing V and Cr. Under the most suitable conditions, including NaOH concentration of 3 mol/L, stripping temperature of 25 °C, O/A ratio of 3:1, the stripping of vanadium and chromium reached more than 99% and less than 8%, respectively, after five-stage counter current stripping. Chromium in the loaded organic solution can be stripped in the form of PbCrO4·PbO precipitate using the stripping system of PbCO3 + NaOH solution. Under the most suitable conditions, including PbCO3 addition with a Pb/Cr molar ratio of 5, NaOH concentration of 0.5 mol/L, O/A ratio of 1:1, stripping temperature of 25 °C, stripping time of 50 min, the stripping of chromium reached 99.1%.

Highly dispersed RuO2-biomass carbon composite made by immobilization of ruthenium and dissolution of coconut meat with octyl ammonium salicylate ionic liquid for high performance flexible supercapacitor

Poor dispersion of metal oxide-biomass carbon composite limits its further improvement in electrochemical properties. The study reports synthesis of highly dispersed RuO2-biomass carbon nanocomposite (HD–RuO2–BC). Octyl ammonium salicylate ionic liquid was combined with Ru3+ ion to form Ru-based ionic liquid. Followed by addition of coconut meat, microwave treatment to form homogeneous solution, thermal reduction in N2 and oxidation in air in sequence. The resulting HD–RuO2–BC shows three-dimensional architecture and high Ru loading of 9.2%. RuO2 nanoparticles of 6.2 nm were uniformly dispersed in biomass carbon sheets. Excellent dispersion and small size of RuO2 nanoparticles achieve to a significant synergy between RuO2 and biomass carbon. HD–RuO2–BC electrode gives high capacitance of 907.7 F g−1 at 1 A g−1. The value is more than that of BC (150.6 F g−1) and RuO2 electrodes (584.7 F g−1), verifying that introduction of RuO2 achieves to an obviously enhanced capacitance. The symmetrical flexible supercapacitor exhibits excellent supercapacitor performances, including high capacitance (403.8 F g−1 at 1.0 A g−1), rate-capacity (223.1 F g−1 at 50 A g−1), cycling stability (98.2% capacity retention after 10,000 cycles at 50 A g−1) and energy density (378.7 Wh Kg−1at power density of 5199.2 W kg−1).

Carbon Capture from Biogas by Deep Eutectic Solvents: A COSMO Study to Evaluate the Effect of Impurities on Solubility and Selectivity

Deep eutectic solvents (DES) are compounds of a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA) that contain a depressed melting point compared to their individual constituents. DES have been studied for their use as carbon capture media and biogas upgrading. However, contaminants’ presence in biogas might affect the carbon capture by DES. In this study, conductor-like screening model for real solvents (COSMO-RS) was used to determine the effect of temperature, pressure, and selective contaminants on five DES’ namely, choline chloride-urea, choline chloride-ethylene glycol, tetra butyl ammonium chloride-ethylene glycol, tetra butyl ammonium bromide-decanoic acid, and tetra octyl ammonium chloride-decanoic acid. Impurities studied in this paper are hydrogen sulfide, ammonia, water, nitrogen, octamethyltrisiloxane, and decamethylcyclopentasiloxane. At infinite dilution, CO2 solubility dependence upon temperature in each DES was examined by means of Henry’s Law constants. Next, the systems were modeled from infinite dilution to equilibrium using the modified Raoults’ Law, where CO2 solubility dependence upon pressure was examined. Finally, solubility of CO2 and CH4 in the various DES were explored with the presence of varying mole percent of selective contaminants. Among the parameters studied, it was found that the HBD of the solvent is the most determinant factor for the effectiveness of CO2 solubility. Other factors affecting the solubility are alkyl chain length of the HBA, the associated halogen, and the resulting polarity of the DES. It was also found that choline chloride-urea is the most selective to CO2, but has the lowest CO2 solubility, and is the most polar among other solvents. On the other hand, tetraoctylammonium chloride-decanoic acid is the least selective, has the highest maximum CO2 solubility, is the least polar, and is the least affected by its environment.

Amplified spontaneous emission properties of solution processed CsPbBr3 perovskite thin films doped with large-group ammonium cations

Inorganic solution processed CsPbBr3 perovskite thin films are highly promising optoelectronic materials and have been applied in solar cells, light emitting diodes, and photodetectors. They show good electroluminescence properties combined with high thermal stability. In this work, CsPbBr3 perovskite thin films doped with a series of organic cations of various chain lengths, namely, methylammonium (MA), ethylammonium (EA), butylammonium (BA) and octylammonium (OA) at optimized molar ratios of (organic cations: Cs+), were fabricated with a two-step solution process. The crystalline structure, surface morphology and photophysical properties of the films were characterized in detail. The surface morphology of the films was improved with reduced surface roughness, accompanying by doping with the organic cations. The amplified spontaneous emissions (ASE) were observed from all of the different CsPbBr3 films at room temperature. The gain coefficients for the doped CsPbBr3 films were higher than the pristine films, due to much reduced bulk defects, reduced non-radiative recombination in the films, as well as improved surface quality of the films. This work provides a simple method of preparing organic cations modified CsPbBr3 laser gain media of high performance.

Chemical and Structural Diversity of Hybrid Layered Double Perovskite Halides.

Hybrid halide double perovskites are a class of compounds attracting growing interest because of their richness of structure and property. Two-dimensional (2D) derivatives of hybrid double perovskites are formed by the incorporation of organic spacer cations into three-dimensional (3D) double perovskites. Here, we report a series of seven new layered double perovskite halides with propylammonium (PA), octylammonium (OCA), and 1,4-butyldiammonium (BDA) cations. The general formulas of the compounds are AmMIMIIIX8 (single-layered Ruddlesden-Popper type with m = 4 and A = PA or OCA, and single-layered Dion-Jacobson type with m = 2 and A = BDA, MI = Ag, MIII= In or Bi, X = Cl or Br) and PA2CsMIMIIIBr7 (bilayered, with MI = Ag, MIII = In or Bi). These families of compounds demonstrate great versatility, with tunable layer thickness, the ability to vary the interlayer spacing, and the ability to selectively tune the band gap by varying the MI and MIII cations along with the halide anions. The band gap of the single-layered materials varies from 2.41 eV for PA4AgBiBr8 to 3.96 eV for PA4AgInCl8. Photoluminescent emission spectra of the layered double perovskites at low-temperature (100 K) are reported, and density functional theory electronic structure calculations are presented to understand the nature of the band gap evolution. The development of new structural and compositions in layered double perovskite halides enhances the understanding of structure-property relations in this important family.

Synthesis of Octyl-Quaternary Ammonium Mixed-Mode Stationary Phase by Vapor Deposition Approach and Its Application in Compound Preparation Separation

An octyl-quaternary ammonium (Sil-C8-QA)-modified silica stationary phase was prepared by a two-step vapor deposition method which can substantially reduce the consumption of toxic organic solvents. The structure of the dual-functional ligands stationary phase was characterized by Fourier transform infrared spectroscopy and solid-state 13C CP/MAS NMR. Following elemental analysis, the surface density of octyl and quaternary ammonium bonding amount is 2.13 µmol m−2 and 0.77 µmol m−2, respectively. The efficiency and selectivity of the two-ligand phases were compared with two sole functional ligand phases: quaternary ammonium (Sil-QA)- and octyl-modified silica (Sil-C8). Chromatographic evaluation demonstrated a mixed-mode reversed-phase/anion-exchange retention property on the Sil-C8-QA column. The retention behavior of a homologous series of alkylbenzoic acids on the synthesized phase was systematically studied by changing the pH, ionic, and solvent strength of the mobile phase. A well-established mixed-model mechanism was confirmed. The Sil-C8-QA phase can predominantly enhance the retention of acidic drugs and improve their selectivity. It was also successfully applied to the simultaneous separation and determination of three kinds of compound preparations with large differences in component polarity.

Crosslinked thermoelectric hydro-ionogels: A new class of highly conductive thermoelectric materials

In this work, a new class of highly-conductive chemically cross-linked gel has been synthesized by the confinement of water and IL N, N, N triethyl octyl ammonium bromide ([N2228] Br) in polyethylene glycol dimethacrylate (PEGDMA) matrix, using in situ thermally initiated radical polymerization loaded with 1 wt% free radical initiator azobisisobutyronitrile (AIBN). This novel gel was named as hydro-ionogel (HIG). The thermoelectric properties of HIG such as ionic conductivity, Seebeck coefficient, and thermal conductivity were measured and owing to its high thermoelectric performance, we referred to this as crosslinked thermoelectric hydro-ionogel, henceforth will be denoted by X-TEHIG. For all the measurements, coin cells were fabricated using commercial LIR 2032 stainless steel battery casings with X-TEHIG sandwiched between the two graphene electrodes. The ionic conductivity of X-TEHIG was examined via AC impedance spectroscopy technique by using a Gamry apparatus. Remarkably, the ionic conductivity of X-TEHIG was higher than that of neat [N2228] Br. A linear increase in ionic conductivity of X-TEHIG as a function of temperature was recorded that showed a considerably higher value of 74 mScm−1 at 70 °C. The origin of this high conductivity is attributed to interactions between PEGDMA monomers and cations and anions of the IL and formation of hydrogen bonds between water and Br− anion, OH⋯Br−. X-TEHIG demonstrated a higher Seebeck coefficient of 1.38 mVK−1. The Fourier transform infrared (FTIR) spectroscopy results revealed the successful polymerization of X-TEHIG by the disappearance of CC peak of methacrylate group in the spectrum of PEGDMA. These results suggest that X-TEHIG may be a potential candidate for thermoelectric applications owing to their high values of ionic conductivity and Seebeck coefficient.

Development of Abraham model IL-specific correlations for N-triethyl(octyl)ammonium bis(fluorosulfonyl)imide and 1-butyl-3-methylpyrrolidinium bis(fluorosulfonyl)imide

ABSTRACTAbraham model correlations are derived for describing gas-to-ionic liquid and water-to-ionic liquid partition coefficients from published experimental data for solutes dissolved in both N-triethyl(octyl)ammonium bis(fluorosulfonyl)imide and 1-butyl-3-methyl-pyrrolidinium bis(fluorosulfonyl)imide. Derived Abraham model correlations describe the observed partition coefficient data to within 0.13 log units. As part of the current study the existing equation coefficients for the N-triethyl(octyl)ammonium cation were updated and reported for the first time were equation coefficients for the bis(trifluorosulfonyl)imide anion.

Modulating Excitonic Recombination Effects through One-Step Synthesis of Perovskite Nanoparticles for Light-Emitting Diodes.

The primary advantages of halide perovskites for light-emitting diodes (LEDs) are solution processability, direct band gap, good charge-carrier diffusion lengths, low trap density, and reasonable carrier mobility. The luminescence in 3 D halide perovskite thin films originates from free electron-hole bimolecular recombination. However, the slow bimolecular recombination rate is a fundamental performance limitation. Perovskite nanoparticles could result in improved performance but processability and cumbersome synthetic procedures remain challenges. Herein, these constraints are overcome by tailoring the 3 D perovskite as a near monodisperse nanoparticle film prepared through a one-step in situ deposition method. Replacing methyl ammonium bromide (CH3 NH3 Br, MABr) partially by octyl ammonium bromide [CH3 (CH2 )7 NH3 Br, OABr] in defined mole ratios in the perovskite precursor proved crucial for the nanoparticle formation. Films consisting of the in situ formed nanoparticles displayed signatures associated with excitonic recombination, rather than that of bimolecular recombination associated with 3 D perovskites. This transition was accompanied by enhanced photoluminescence quantum yield (PLQY≈20.5 % vs. 3.40 %). Perovskite LEDs fabricated from the nanoparticle films exhibit a one order of magnitude improvement in current efficiency and doubling in luminance efficiency. The material processing systematics derived from this study provides the means to control perovskite morphologies through the selection and mixing of appropriate additives.

A Versatile Route for the Synthesis of Iron Oxide Nanostructures by Electrochemical Reduction Method and Their Antibacterial Application

Nanoscience is one of the most important research in modern science. The preparation of monodisperse-sized nanocrystals is very important because the properties of these nanocrystals depend strongly on their dimensions. The preparation of monodisperse-sized nanocrystals with controllable sizes is very important to characterize the size-dependent physicochemical properties of nanocrystals. Iron, the most ubiquitous of the transition metals and the fourth most plentiful element in the Earths crust, is the structural backbone of our modern infrastructure. The nanostructured iron oxide (IONPs) were synthesized by electrochemical reduction method using tetra octyl ammonium bromide as structure directing agent in an organic medium viz. tetra hydro furan and acetonitrile in 1:4 ratio by optimizing current density 12 mA/cm2. Such nanoparticles were prepared using simple electrolysis cell in which the sacrificial anode was as a commercially available iron metal sheet and platinum (inert) sheet acted as a cathode. The synthesized iron oxide nanoparticles were characterized by using ultra violet–visible spectroscopy, infra red spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscope analysis techniques. The nanoparticles were tested for antibacterial activity against human pathogens like gram negative Escherichia coli, Salmonella typhi and gram positive Staphylococcus aureus, Bacillus subtilis strains, which showed excellent antibacterial properties.

The accelerating effect of a small cationic quaternary ammonium compound and the adsorption kinetics in the dyeing of silk with reactive dyes

In order to develop an eco‐friendly method for silk reactive dyeing that uses a lower accelerant dosage to achieve a higher dye fixation, hexyl dimethyl octyl ammonium chloride was synthesised as an accelerant for the dyeing of silk with reactive dyes. The accelerating effect, corresponding adsorption kinetics, and interaction mechanisms among hexyl dimethyl octyl ammonium chloride, reactive dyes, and silk were investigated. At hexyl dimethyl octyl ammonium chloride concentrations of 10.8–14.4 mm, the dye fixations for three reactive dyes were much higher than those achieved with sodium sulfate, even though the required dosages of hexyl dimethyl octyl ammonium chloride were 30–40 times lower than those of sodium sulfate. The wash fastness, rub fastness, light fastness, K/S, and colour difference values after dyeing with hexyl dimethyl octyl ammonium chloride were similar to those obtained using sodium sulfate, and silk can be dyed uniformly. The adsorption kinetics followed a second‐order kinetic model. The activation energies of surface adsorption for the three reactive dyes were lower than those of sodium sulfate. The high fixation of reactive dyestuffs and the low required dosage of hexyl dimethyl octyl ammonium chloride demonstrate that the use of this new accelerant provides a novel, highly efficient method for silk dyeing. A possible acceleration mechanism of hexyl dimethyl octyl ammonium chloride for reactive dyes adsorbed on the surface of silk was proposed, based on a series of activation parameters of the adsorption process.

Partition Coefficients of Organic Compounds in Four New Tetraalkylammonium Bis(trifluoromethylsulfonyl)imide Ionic Liquids Using Inverse Gas Chromatography

The activity coefficients at infinite dilution, γ1,2∞, of 47 solutes including various (cyclo)alkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, aldehydes, and ketones, in the four ionic liquids (ILs) decyl(trimethyl)ammonium bis(trifluoromethylsulfonyl)imide, methyl(tributyl)ammonium bis(trifluoromethylsulfonyl)imide, octyl(trimethyl)ammonium bis(trifluoromethylsulfonyl)imide, and tetraoctylammonium bis(trifluoromethylsulfonyl)imide, were measured using inverse gas chromatography at temperatures from (323 to 343) K. The retention data were also converted to gas-to-IL and water-to-IL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analyzed using the modified Abraham solvation parameter model. The derived equations correlated the experimental gas-to-IL and water-to-IL partition coefficient data to within average standard deviations of 0.100 and 0.133 log units, respectively.