Aqueous Tetrabutylammonium Bromide Solutions Research Articles

Freezing fouling from aqueous solutions of TBAB and TME clathrate hydrates

Crystallisation fouling caused by cooling of aqueous solutions of 10–40 wt% tetrabutylammonium bromide (TBAB) and trimethyloethane (TME) was studied in a two-fingered deposition cell. The clathrates formed semi-solid layers of crystals on the heat transfer surfaces. DSC studies confirmed the existence of different hydration states, particularly for TBAB, which could be described reasonably well by simple models. The enthalpy of fusion measured with DSC was 50–300 J g−1 for aqueous TBAB solutions up to 60 wt% and 150–320 J g−1 for up to 80 wt% TME. Fickian diffusivities estimated using DOSY NMR were 0.5–4 × 10-10 m2 s−1 for TBAB and 2–5 × 10-10 m2 s−1 for TME 10–50 wt% solutions. A quantitative model describing the rate of crystal layer growth based on combined heat and mass transfer control gave good agreement with experimental data and indicated that the fraction of crystals in the matrix approached 40 vol%.

Modeling study on phase equilibria of semiclathrate hydrates of pure gases and gas mixtures in aqueous solutions of TBAB and TBAF

Quaternary ammonium salts (QASs) such as tetrabutyl ammonium bromide (TBAB) and fluoride (TBAF) can form semiclathrate hydrates with water molecules at atmospheric pressure. Recently, the semiclathrate hydrates have attracted more and more interests for their wide applications, such as the storage and transportation of natural gas or coal bed methane, separation of low-boiling gases and carbon dioxide sequestration at mild conditions. In this work, the modeling investigations were conducted for the TBAB and TBAF semiclathrate hydrates with different gases such as CH4, CO2, N2, and their mixtures. The Chen-Guo hydrate model was extended to the semiclathrate hydrate systems. The thermodynamic properties of the gas phase were described with the Patel-Teja equation of state (PT EOS). The PT EOS combined with a Debye-Huckel electrostatic contribution term was chosen to describe the thermodynamic properties of the electrolyte solution. The parameters in the EOS for ions were determined by fitting the thermodynamic properties of the electrolyte solution. The parameters of TBAB and TBAF in the hydrate model were obtained from correlating the equilibrium data of semiclathrate hydrates. The extensive tests show that the proposed model results are in acceptable agreement with the experimental data on phase equilibria of semiclathrate hydrate systems.

Thermal conductivity measurements of semiclathrate hydrates and aqueous solutions of tetrabutylammonium bromide (TBAB) and tetrabutylammonium chloride (TBAC) by the transient hot-wire using parylene-coated probe

The thermal conductivity of semiclathrate hydrates and aqueous solutions of tetrabutylammonium bromide (TBAB) and tetrabutylammonium chloride (TBAC) was measured for the first time in the temperature range from 223 to 303 K under atmospheric pressure. A transient hot-wire apparatus using a parylene-coated probe was employed for the measurements with an uncertainty of ±0.7%. The experimental results indicate that the thermal conductivity of two semiclathrate hydrates are smaller than those of two clathrate hydrates—about 80% of the THF hydrate and 60% of the CH4 hydrate—and are about a factor of 5.5 lower than that of ice Ih at temperatures near the melting point. In addition, the temperature coefficient of the thermal conductivity of semiclathrate hydrate show a weak negative, and the thermal conductivity is more sensitive to the molar mass of a guest molecule.

Study of tetrabutylammonium bromide in aqueous solution by neutron scattering

The study of electrolyte solutions by neutron scattering is an example of the large range of possibilities of the technique. Structure and dynamics at different time and length scales, discrimination of global from local motions, separation of coherent from incoherent contributions are necessary to embrace the complexity of a subject where charge and hydrophobicity play important and competitive roles. The behaviour of aqueous solutions of tetrabutylammonium bromide is studied here by several neutron scattering techniques: Small Angle Neutron Scattering, Neutron Diffraction, Time-of-Flight and Neutron Spin Echo. We concentrate on the conformation and dynamics of the hydrophobic cations. In particular, the center-of-mass (CoM) motion of the cation at the microscopic scale is best described via the low Q coherent signal, as measured by Neutron Spin Echo. Due to a possible cage formation effect in the TBABr solution, at the scale of the distance between cations, the cationic CoM relaxation time is larger than that predicted by a simple extrapolation of results issued from the hydrodynamic regime and those obtained from the incoherent signal analysis.

Measurement of the three-phase (vapour + liquid + solid) equilibrium conditions of semi-clathrates formed from mixtures of CO2, CO and H2

Semi-clathrates were formed in an isochoric equilibrium-cell, from gaseous mixtures of (CO2+H2+CO), in aqueous solutions of tetra-butyl ammonium bromide (TBAB). The experimental temperatures ranged between (282 and 291)K, experimental pressures ranged between (2.6 and 6.6) MPa and the experiments were conducted in aqueous TBAB solutions of wTBAB=(0.05, 0.10, and 0.20). The gas phase composition was analysed, using gas chromatography, and it was observed that the amount of CO2 in the gas phase was reduced. Additionally, the experimental results were compared to the formation conditions required for gas hydrates, that are formed from the same gas mixtures, and it was observed that the pressure required for semi-clathrate formation was significantly less than that required for gas hydrate formation.

Experimental investigation of incipient equilibrium conditions for the formation of semi-clathrate hydrates from quaternary mixtures of (CO 2 + N 2 + TBAB + H 2O)

The three-phase (vapour + liquid + solid) equilibrium conditions for semi-clathrates formed from three mixtures of (CO 2 + N 2), in aqueous solutions of tetra-butyl ammonium bromide (TBAB), were measured in an isochoric reactor. The experiments were conducted at temperatures between (281 and 290) K, at pressures between (1.9 and 5.9) MPa and in aqueous TBAB solutions of w TBAB = (0.05, 0.10, and 0.20). The experimental results obtained in this study were compared with previously obtained results for gas hydrates, formed from the same three mixtures of (CO 2 + N 2) and it was observed that semi-clathrates formed at a substantially lower pressure than did gas hydrates.

Physicochemical investigation on interactions of some amino acids with aqueous tetra-butyl ammonium bromide solution at 298.15 K

Apparent molar volumes, viscosity B-coefficients, and apparent molar isentropic compressibilities of glycine, L-alanine, L-valine and L-leucine in 0.062, 0.125 and 0.256 mol kg−1 aqueous tetra-butyl ammonium bromide (TBAB) solution have been determined at 298.15 K from their experimental density, flow time and sound speed measurements, respectively. The standard partial molar volumes and compressibilities are used to calculate the corresponding volume of transfer at infinite dilution, from water to aqueous TBAB solutions. The linear correlation of partial molar volumes for a homologous series of amino acids has been utilised to calculate the contribution of charged end groups and other alkyl chains of the amino acids to partial molar volumes. The hydration numbers of amino acids have also been determined. Viscosity B-coefficients have been calculated using the Jones–Dole equation. The values of the charged end groups contribution to the viscosity B-coefficients of the amino acids are calculated.

Apparent molar volumes and viscosity B-coefficients of nicotinamide in aqueous tetrabutylammonium bromide solutions at T = (298.15, 308.15, and 318.15) K

Apparent molar volumes ϕ V and viscosity B-coefficients for nicotinamide in (0.00, 0.05, 0.10, and 0.15) mol · dm −3 aqueous tetrabutylammonium bromide (TBAB) solutions have been determined from solution density and viscosity measurements at temperatures over the range (298.15 to 318.15) K as function of concentration of nicotinamide (NA). In the investigated temperature range, the relation: ϕ V ∘ = a 0 + a 1 T + a 2 T 2 , have been used to describe the temperature dependence of the standard partial molar volumes ϕ V ∘ . These results have, in conjunction with the results obtained in pure water, been used to deduce the standard volumes of transfer Δ ϕ V ∘ and viscosity B-coefficients of transfer for nicotinamide from water to aqueous TBAB solutions for rationalizing various interactions in the ternary solutions. The structure making or breaking ability of nicotinamide has been discussed in terms of the sign of ( δ 2 ϕ V ∘ / δ T 2 ) P . An increase in the transfer volume of nicotinamide with increasing TBAB concentration has been explained by Friedman–Krishnan co-sphere model. The activation parameters of viscous flow for the ternary solutions investigated were also determined and discussed by the application of transition state theory.

Solubility of helium and methane in aqueous tetrabutylammonium bromide solutions at 25 and 35.deg.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolubility of helium and methane in aqueous tetrabutylammonium bromide solutions at 25 and 35.deg.Andre Feillolay and Michel LucasCite this: J. Phys. Chem. 1972, 76, 21, 3068–3072Publication Date (Print):October 1, 1972Publication History Published online1 May 2002Published inissue 1 October 1972https://doi.org/10.1021/j100665a028RIGHTS & PERMISSIONSArticle Views81Altmetric-Citations17LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (595 KB) Get e-Alerts