Álvaro Pérez-Salado Kamps

Chemical equilibrium constants for the formation of carbamates in (carbon dioxide + piperazine + water) from 1H-NMR-spectroscopy

Abstract 1 H -NMR spectroscopic investigations were performed on aqueous solutions of carbon dioxide and piperazine at temperatures ranging from (283 to 333) K to determine quantitatively the speciation. The experimental results were used to determine the chemical equilibrium constants for the formation of piperazine carbamate, piperazine dicarbamate and protonated piperazine carbamate.

Solubility of tetrafluoromethane in the ionic liquid [hmim][Tf2N].

Experimental results for the solubility of tetrafluoromethane (CF4, R14) in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([hmim][Tf2N]) are presented for temperatures between 293.3 and 413.3 K, at pressures (gas molalities) up to 9.6 MPa (0.22 mol kg-1). The experimental results were determined with a high-pressure view-cell technique operating on the synthetic method. The experimental data were used to determine Henrys constant of tetrafluoromethane in [hmim][Tf2N]. The results for the Henrys constant (at zero pressure) are correlated (on the molality scale) within the experimental uncertainty (i.e., about 1.1%) by ln(k(0)(H,CF4)/MPa) = 7.537 - 893.8/(T/K) - 0.003977(T/K). Henrys law was also extended to describe the gas solubility at higher pressures. Furthermore, a cubic equation of state was used to correlate the gas solubility over the entire range of experimentally investigated temperature and pressure. Both methods proved suited for a reliable correlation of the new experimental data.

Solubility of hydrogen sulfide in aqueous solutions of single strong electrolytes sodium nitrate, ammonium nitrate, and sodium hydroxide at temperatures from 313 to 393 K and total pressures up to 10 MPa

Abstract New experimental results for the solubility of hydrogen sulfide in aqueous solutions of the single strong electrolytes sodium nitrate, ammonium nitrate, and sodium hydroxide at temperatures from 313 to 393 K and total pressures up to 10 MPa are reported. As in the strong electrolyte-free system, a second — hydrogen sulfide-rich — liquid phase is observed at high hydrogen sulfide concentrations. A thermodynamic model for describing the phase equilibrium is presented. Calculations are compared with the new experimental data.

Chapter 4:Solubility of Gases in Ionic Liquids, Aqueous Solutions, and Mixed Solvents

The solubility of gases in liquids is of interest in many applications. There have been many publications on this subject over a period of more then a century. Nevertheless, gas solubility is still an important area of research from both an experimental point of view and from a theoretical point of ...

A Study on the Influence of Na2SO4 on the Solubility of CO2 in Aqueous Solutions of (N,N-dimethylmethanamide)

Abstract The influence of sodium sulphate on the solubility of carbon dioxide in aqueous solutions of N,N-dimethylmethanamide {= N,N-dimethylformamide, (CH3)2N-C(H)O, DMF} was investigated experimentally at three temperatures (314 K, 354 K, and 395 K). The solvent was an aqueous solution of DMF (mole fraction of DMF in the salt-free solution ≈ 0.05) and sodium sulphate (molality ≈ 0.6 mol·(kgH2O)−1). The maximum pressure of the new experimental gas solubility data reaches nearly 10 MPa. A thermodynamic model that combines two models for the solubility of CO2 (in aqueous solutions of Na2SO4 on one side and in aqueous solutions of DMF on the other side) is used to predict the influence of Na2SO4 on the solubility of CO2 in aqueous solutions of DMF. The new experimental data are compared with such predictions and with calculations from an extension of that model where a single ternary parameter for interactions between the three solutes (i.e., CO2, Na2SO4, and DMF) is adjusted to improve the representation of the experimental data.