Ammonium Bromide Aqueous Solution Research Articles

Motility and pairwise interactions of chemically active droplets in one-dimensional confinement.

Self-propelled droplets serve as ideal model systems to delve deeper into understanding the motion of biological microswimmers by simulating their motility. Biological microorganisms are renowned for showcasing a diverse array of dynamic swimming behaviors when confronted with physical constraints. This study aims to elucidate the impact of physical constraints on swimming characteristics of biological microorganisms. To achieve this, we present observations on the individual and pairwise behavior of micellar solubilized self-propelled 4-cyano-4'-pentyl-biphenyl (5CB) oil droplets in a square capillary channel filled with a surfactant trimethyl ammonium bromide aqueous solution. To explore the effect of the underlying Péclet number of the swimming droplets, the study is also performed in the presence of additives such as high molecular weight polymer polyethylene oxide and molecular solute glycerol. The capillary confinement restricts droplet to predominantly one-dimensional motion, albeit with noticeable differences in their motion across the three scenarios. Through a characterization of the chemical and hydrodynamic flow fields surrounding the droplets, we illustrate that the modification of the droplets' chemical field due to confinement varies significantly based on the underlying differences in the Péclet number in these cases. This alteration in the chemical field distribution notably affects the individual droplets' motion. Moreover, these distinct chemical field interactions between the droplets also lead to variations in their pairwise motion, ranging from behaviors like chasing to scattering.

Modeling Tetra-n-butyl ammonium halides aqueous solutions with the electrolyte cubic plus association equation of state

This work presents the thermodynamic modeling of the fluid phases of Tetra-n-butyl ammonium halides aqueous solutions with the electrolyte Cubic-Plus-Association (e-CPA) Equation of State (EOS). The adjustable model parameters are obtained by fitting the experimental data of mean ionic activity coefficients and osmotic coefficients. Several other thermodynamic properties of the aqueous solutions, such as relative static permittivity, liquid density and saturation pressure, are subsequently predicted by the e-CPA EOS. The results of Tetra-n-butyl ammonium bromide aqueous solution show that the model can satisfactorily correlate the mean ionic activity coefficients and osmotic coefficients with the percentage average absolute deviations being 7.2% and 5.9%. The model overpredicts the liquid density with a deviation of 9.2%, while it can correlate the liquid density within 0.2% with a volume translation parameter. In order to have a more complete picture of the capabilities and limitations of the model, the consistencies of experimental data, parameter estimation approaches and the ion sizes are extensively analyzed and discussed.

Phase equilibria prediction model for semiclathrate hydrates formed from CH4, CO2, and N2 in the presence of tetra-n-butyl ammonium bromide

ABSTRACTIn this work, a prediction model was studied and carried out to predict phase equilibrium conditions for semiclathrate hydrates formed from the ternary system of liquid water, tetra-n-butyl ammonium bromide, and CO2, CH4, or N2. Based on the Soave–Redlich–Kwong equation of state along with the Chen–Guo model, the predictions of phase equilibria of semiclathrates of CO2, CH4, and N2 + pure water/tetra-n-butyl ammonium bromide aqueous solution has been made. A new correlation for activity relating to the system temperature and tetra-n-butyl ammonium bromide concentration has been proposed. The prediction results were analyzed and showed good agreement with the experimental data.

Experimental measurement and thermodynamic modelling of hydrate phase equilibrium conditions for krypton + n-butyl ammonium bromide aqueous solution

In this study, experimental hydrate dissociation data for krypton in the presence of aqueous solutions of TBAB at varying concentrations of 0, 0.05, 0.10 and 0.20mass fraction TBAB were measured. The measurements were undertaken in the temperature range of (274.1 to 297.1) K and pressures ranging from (0.22 to 11.97) MPa. In addition, semi-clathrate hydrate dissociation data for the TBAB+water system at a pressure of 99.8kPa and at various TBAB concentrations of 0.05, 0.10, 0.20 and 0.30mass fractions were measured. The isochoric pressure-search method was used to undertake the measurements. The purpose of this study was to investigate the effect of TBAB aqueous solution on krypton hydrates. The results reveal that the TBAB aqueous solutions with concentrations of 0.05, 0.10 and 0.20mass fractions show a drastic promotion effect on the krypton hydrate causing a shift of the P-T equilibrium line to lower pressures and higher temperatures. In addition, increasing the TBAB concentration increases its promotion effect. The hydrate dissociation conditions for krypton+water+TBAB system were represented using a model based on the work of Chen and Guo, (Chem. Eng. J. 71 (1998) 145–151) and Joshi et al. (J. Nat. Gas Chem. 21 (2012) 459–465). The model results show a satisfactory agreement with the experimental data, with an absolute relative deviation (ARD%) below 0.3%.

A facile synthesis of novel mesoporous bioactive glass nanoparticles with various morphologies and tunable mesostructure by sacrificial liquid template method

In this paper, two types of mesoporous bioactive glasses (MBGs) including spherical MBGs (SBG) with radial mesostructure and pineal MBGs (PBG) with lamellar mesostructure have been successfully synthesized through a novel sacrificial liquid template method in sol–gel process. The morphologies and structures of the samples were characterized and the results demonstrated that ethyl acetate was added in the hexadecy ltrimethyl ammonium bromide aqueous solution to form micro-emulsion droplets as liquid template; the aqueous ammonia was added as template corrodent and hydrolysis catalyst. The morphology of MBGs could be controlled by the reaction conditions. Meanwhile, the size and the mesostructure of MBGs could be tuned by the aqueous ammonia concentration. The novel MBGs may be a good candidate as therapeutic molecules carriers for bone and dental tissue regeneration.

Polyoxometalate‐Based Metal–Organic Frameworks as Catalysts for the Selective Oxidation of Alcohols in Micellar Systems

AbstractA series of nanosized metal–organic frameworks (MOFs) encapsulating different polyoxometalates (POMs) including H3PW4O12, H5PMo12O40, H5PVMo10O40, H5PV2Mo10O40, and H5PV3Mo10O40 was synthesized and used in the selective oxidation of alcohols. The catalyst with a uniform size and morphology offered easy accessibility between substrates and catalyst. At the same time, the MOF ensured that the POM was encapsulated, which could dramatically prevent the assembly of the catalyst. Furthermore, the catalyst showed clear chemoselectivity, which was related to the size or accessibility of the substrates for surface pores. With cetyltrimethyl ammonium bromide aqueous solution as solvent, both improved reaction efficiency and simple recycling of the catalytic system were achieved to afford a green oxidation process.

Experimental study on effect of electric field on hydrate nucleation in supercooled tetra-n-butyl ammonium bromide aqueous solution

The effect of an electric field on hydrate nucleation in supercooled tetra-n-butyl ammonium bromide (TBAB) aqueous solution was investigated experimentally. Experiments were carried out by charging electrodes inserted into a test tube containing TBAB aqueous solution using a DC voltage. The electrode material (copper, aluminum, nickel, iron and gold), value of applied voltage and sample concentration were varied as the experimental parameter. When the sample was maintained under a supercooled state, the DC voltage was applied directly to the TBAB aqueous solution for 1 min. It was found that the probability of nucleation depends on the electrode material. The probability of nucleation is especially high in the case of the Cu electrode. It was also found that the probability of nucleation of type 2 TBAB hydrate is lower than that of type 1 hydrate under these experimental conditions.

Fabrication of Amphiphilic Gold Nanoparticles of Well-Defined Size, High Concentration and Robust Colloidal Stability Fabrication of Amphiphilic Gold Nanoparticles of Well-Defined Size, High Concentration and Robust Colloidal Stability Fabrication of Amphiphilic Gold Nanoparticles of Well-Defined Size, High Concentration and Robust Colloidal Stability

Herein, we reported an efficient and universal protocol to prepare gold nanoparticles capped by a dodecanethiol and cetyltrimethyl ammonium bromide interdigitated bilayer which could be dispersed well in either aqueous or organic solvents without additional phase transfer reagents. The gold nanoparticles were synthesized in a micro-emulsion method with transferring the precursor hydrophobic dodecanethiol-capped gold nanoparticles into cetyltrimethyl ammonium bromide aqueous solution. The advantage of this work consists in controlling the diameter of the core gold nanoparticles by capping of dodecanethiol, obtaining high concentration and robust colloidal stability monodisperse amphiphilic gold nanoparticles of various sizes in 2 nm, 5 nm and 7.5 nm, which is very difficult to realize with other methods as far as we known. Very few change existed in the size and intrinsic optical property during the conversion from the aqueous phase to the organic phase and back to aqueous phase, showing these size-controllable amphiphilic gold nanoparticles can be applied not only in biological labeling and sensing, design of diagnostic and therapeutic due to their aqueous soluble biological compatibility, but also in assembling ordered 2D or 3D superlattice due to their monodispersity and high concentration.

Thermodynamic stability of hydrogen [formula omitted] tetra- n-butyl ammonium bromide mixed gas hydrate in nonstoichiometric aqueous solutions

Phase equilibrium (pressure–temperature) relations of the hydrogen + tetra- n-butyl ammonium bromide mixed gas hydrate system have been measured for various concentrations of tetra- n-butyl ammonium bromide aqueous solutions. The three-phase equilibrium curves obtained in the present study are shifted to the low-temperature or high-pressure side from that of the stoichiometric tetra- n-butyl ammonium bromide solution. Each three-phase equilibrium curve of hydrogen + tetra- n-butyl ammonium bromide mixed gas hydrate converges at the atmospheric equilibrium point of the pure tetra- n-butyl ammonium bromide hydrate for the mother aqueous solution of same mole fraction. The hydrate-cage occupancy of hydrogen in the hydrogen + tetra- n-butyl ammonium bromide mixed gas hydrate is in variable in a range of tetra- n-butyl ammonium bromide mole fraction from 0.006 to 0.070 in the aqueous solution. Hydrogen is entrapped only in the small cages of tetra- n-butyl ammonium bromide hydrates.

Density, Kinematic Viscosity, Speed of Sound, and Surface Tension of Tetradecyl and Octadecyl Trimethyl Ammonium Bromide Aqueous Solutions

Density, kinematic viscosity, surface tension, and speed of sound of tetradecyl and octadecyl trimethyl ammonium bromide aqueous solutions have been determined. The influence of each surfactant concentration upon these physical properties has also been studied at 298 K. The experimental values of these physical properties have been employed to determine the critical micellar concentration for each surfactant, as well as to analyze the effect of chain length upon this characteristic parameter.

Density, Kinematic Viscosity, Speed of Sound, and Surface Tension of Hexyl, Octyl, and Decyl Trimethyl Ammonium Bromide Aqueous Solutions

Density, kinematic viscosity, surface tension, and speed of sound of hexyl, octyl, and decyl trimethylammonium bromide aqueous solutions have been determined. The influence of each surfactant concentration upon these physical properties has also been studied at 298 K. The experimental values of these physical properties have been employed to determine the critical micellar concentration for each surfactant as well as to analyze the effect of chain length upon this characteristic parameter.

Ultrasound‐Promoted Magnesium‐Ammonium Bromide–Mediated Pinacol Coupling of Aromatic Aldehydes and Ketones

Abstract Pinacol coupling of aromatic aldehydes and ketones by Mg powder in 0.1‐mol/L ammonium bromide aqueous solution can lead to the corresponding pinacols in 22–90% yields within 1–3 h at rt under ultrasound irradiation.