Mixtures Of N-methyldiethanolamine Research Articles

Vapor–Liquid Equilibria of H2S in Aqueous Mixtures of N-Methyldiethanolamine + Piperazine + Sulfolane

Vapor–Liquid Equilibria of H₂S in Aqueous Mixtures of <i>N</i>-Methyldiethanolamine + Piperazine + Sulfolane

Reaction kinetics of carbon dioxide in aqueous blends of N-methyldiethanolamine and glycine using the stopped flow technique

Carbon dioxide managements and its association with global worming remains a major concern among governments and the scientific community, with novel, energy efficient and more affordable technologies topping the research agendas. Despite the importance of amino acids, their use as reaction promoters in combination with alkanolamines has been overlooked by researchers. Here, stopped-flow technique was used for the first time to measure the pseudo-first-order reaction kinetics of CO2 with various aqueous mixtures of N-methyldiethanolamine (MDEA) and glycine (Gly). The experiments were performed at a temperature range from 293 to 313 K and a total amine concentration up to 2 mol/l. The activation energy for CO2-MDEA reaction obtained from this work was found to be 49.24 kJ/mol, and the overall rate constants (kov) increased with increasing temperature and with increasing proportion of Glycine in the solution mixture. Using the zwitterion mechanism to interpret the CO2-MDEA-Gly reaction, we found that the glycine reacts with CO2 (aq) with k2 (M−1 s−1) = 2.40 × 107 exp(−3887.5/T(K)) with an activation energy of 22.95 kJ/mol.

Densities and excess molar volumes of the binary system N-methyldiethanolamine + (2-aminoethyl)ethanolamine and its ternary aqueous mixtures from 283.15 to 363.15 K

ABSTRACTExperimental density data of the binary mixtures of N-methyldiethanolamine + (2-aminoethyl)ethanolamine and the ternary mixtures of N-methyldiethanolamine + (2-aminoethyl)ethanolamine + water were reported at atmospheric pressure over the entire composition range at temperatures from 283.15 to 363.15 K. Density measurements were performed using an Anton Paar digital vibrating U-tube densimeter. Excess molar volumes were calculated from the experimental data and correlated as the Redlich-Kister equation for the binary mixtures, and as the Nagata-Tamura equation for the ternary mixtures. Several empirical models were applied to predict the excess molar volumes of ternary mixtures from the corresponding binary mixture values. It indicates that the best agreement with the experimental data was achieved by the Redlich-Kister, Kohler, and Jacob-Fitzner models.

High pressure measurement and thermodynamic modelling of the solubility of carbon dioxide in N-methyldiethanolamine and 1-butyl-3-methylimidazolium acetate mixture

In the present work, the equilibrium solubility of carbon dioxide (CO2) in mixtures of N-methyldiethanolamine (MDEA) and 1-butyl-3-methylimidazolium acetate ionic liquid ([bmim][acetate]) is measured at temperatures (303.15 to 343.15)K and over a pressure range of (0.1 to 3.9)MPa. The mass fraction compositions of the MDEA and [bmim][acetate] in the mixture are (0.3,0.7) and (0.5,0.5), respectively. The experimental results are presented as the partial pressure of CO2 against its molality (mol CO2 per kg of solvent) and mole fraction of CO2. Moreover, using the measured values, the enthalpy of solution for the CO2 solubility in the mixtures is calculated. Considering the present results at the given conditions, it is observed that replacing the aqueous media of the MDEA solution by [bmim][acetate] can reduce significantly the enthalpy of solution of CO2 in the solvent.For thermodynamic modelling, a new equation of state (PR-TS EoS) is extended by combining the Peng–Robinson (PR) equation of state as a cubic term for non-specific energy contribution and the Two-State Association Model (TSAM) for association energy contribution based on the frame of the cubic plus equation of state. Furthermore, the PR-TS EoS is applied to correlate the new experimental data of this work. To model the ternary (CO2+MDEA+[bmim][acetate]) system, the parameters of the PR-TS EoS are first adjusted for the pure components. Subsequently, the solubility of CO2 in pure [bmim][acetate] is correlated so that the binary molecular interaction parameters for this binary sub system are optimised. Finally, the equilibrium solubility of CO2 in ternary mixture of {MDEA+[bmim][acetate]} correlates with the per cent average absolute deviation (AAD%) of 11.78 between the calculated and experimental partial pressure of CO2.

Simultaneous measurement solubility of carbon dioxide + hydrogen sulfide into aqueous blends of alkanolamines at high pressure

Treatment of the sour natural gas is a major step in natural gas processing so that the acid gases such as H2S and CO2 are removed from natural gas stream. The acid gases are harmful to environment and destroy the production equipment so that their presence in gas stream leads to corrosion and lowering heating value. On the other hand, for reliable and optimum design of separation equipment, primarily sufficient and accurate equilibrium data of the acid gases solubility in the aqueous alkanolamines is required. In this work, the simultaneous solubility of the H2S+CO2 in the alkanolamine mixtures is measured at 343K and total pressure range of 0.1–2.1MPa. The blends are studied as the aqueous mixtures of N-methyldiethanolamine (MDEA)+2-amino-2-methyl-1-propanol (AMP)+Piperazine (Pz) and the aqueous mixtures of diisopropanolamine (DIPA), AMP and Pz. For the acid gas solubility measurements, a high pressure static apparatus is used through a volumetric method. The mass fraction of the total alkanolamine is fixed at 0.45 and the results are presented as the partial pressure of each acid gas against its loading (mole acid gas/total mole amine) and mole fraction. The influence of the AMP and Pz on the aqueous DIPA-based and MDEA-based systems are studied so that it is observed that the absorption of the CO2 in the aqueous alkanolamine enhances through separate blending of the AMP and Pz with the aqueous system of MDEA or DIPA and the absorption of the H2S reduces in both of the aqueous DIPA-based and MDEA-based systems.

Physical properties of aqueous mixtures of N-methyldiethanolamine (MDEA) and ionic liquids

In the present study, experiments have been conducted to measure the surface tension and heat capacity of aqueous mixtures of N-methyldiethanolamine (MDEA) and ionic liquids (ILs) at atmospheric pressure. Two types of ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4] and 1-butyl-3-methyl-imidazolium dicyanamide [bmim][DCA]) were used in these experiments. The surface tension was found to decrease with increasing temperature and ionic liquid concentration. Furthermore, the heat capacity of the mixtures increases with decreasing ionic-liquid concentration and increasing temperature. Linear equations were used to correlate the measured surface tension values, quadratic equations were applied to correlate the heat capacity at different compositions and temperatures.

Volumetric and viscometric behaviour of the binary systems of N-methyldiethanolamine and diethanolamine with 1-butyl-3-methylimidazolium acetate at various temperatures

In the present work, density and viscosity of two binary mixtures of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) with 1-butyl-3-methylimidazolium acetate ([bmim][acetate]) are measured. The experiments were carried out at atmospheric pressure and at T=(293.15 to 343.15)K for density and from 293.15K to 353.15K for viscosity over the whole range of mole fraction. Using the density and viscosity results, several physical and thermodynamic properties such as excess molar volumes (VE), coefficients of thermal expansions (α), viscosity deviation (Δη),molar activation entropy (ΔS), molar activation enthalpy (ΔH) and molar activation Gibbs free energy (ΔG) for these binary mixtures are calculated.The experimental results of the density and viscosity for the pure systems as well as the binary systems show a decrease with increasing temperature as expected. The results of density measurements show that over all ranges of temperatures investigated the density of the pure components show the following trend: DEA>[bmim][acetate]>MDEA. Therefore, in the binary mixtures of the (MDEA+[bmim][acetate]), the density of the mixture reduces with decreasing concentration of the ionic liquid and for the (DEA+[bmim][acetate]) mixture the density of the blend enhances to reduce the concentration of the ionic liquid. Moreover, the calculated excess molar volumes show a positive deviation from ideality for the two binary mixtures. The behaviour of change of viscosity against concentration for the (MDEA+[bmim][acetate]) system is different from the (DEA+[bmim][acetate]) mixture so that for the first system the value of the viscosity rises with increasing [bmim][acetate] mole fraction, but in the second system there is a minimum viscosity point in the DEA-rich region.

Densities and Viscosities for Binary Mixtures ofN-Methyldiethanolamine + Triethylene Glycol Monomethyl Ether from 25 °C to 70 °C andN-Methyldiethanolamine + Ethanol Mixtures at 40 °C

This paper reports the measured values of the density and viscosity of binary mixtures of N-methyldiethanolamine (MDEA) and triethylene glycol monomethyl ether (TEGMME) at five temperatures in the range 25 °C to 70 °C over the whole concentration range. We also report the density and viscosity of the binary mixture MDEA + ethanol at 40 °C. The results are compared with data for aqueous mixtures and other alkanolamines when these are available. The derived excess molar volumes and viscosity deviations were correlated as a function of composition. The Grunberg−Nissan interaction energy constants are also reported.