Phase behavior of the ternary 1-hexyl-3-methylimidazolium tetrafluoroborate + carbon dioxide + methanol system

The phase behavior of the ternary system consisting of the ionic liquid (IL) 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim+][BF4-]) + carbon dioxide (CO2) + methanol is studied experimentally using the Cailletet apparatus. Experimental data for all phase transitions within a temperature range of 254.64–348.17 K, a pressure range of 2.102–13.189 MPa and a CO2 fraction range of 40.20–69.98 mol% are collected, while the ratio [hmim+][BF4-]:methanol is kept constant at 1:19. Only at CO2 concentrations between 66.47 and 68.04% the usual ‘two-phase’–‘three-phase’–‘two-phase’–‘one-phase’ transition upon CO2 pressure increase is found. At lower and higher CO2 fractions, the number of phase transitions observed is lower. All observed phase transitions do not involve criticalit

Solubility of carbon monoxide in methyl methacrylate at high pressures

Methyl methacrylate (MMA) is an important raw material in the polymer industries. The conventional method of producing methyl methacrylate had the disadvantages of dealing with very toxic raw material and producing large amounts of waste. A new and more environmental friendly route for producing methyl methacrylate involves carbon monoxide. Therefore, it is of significance to have accurate knowledge of the phase equilibria for mixtures of carbon monoxide and methyl methacrylate. In this study, we have determined the high-pressure vapour-liquid equilibria of this binary mixture within a temperature range of 313-318 K and pressures up to 12 MPa. Experiments were carried out using the Cailletet equipment, which is highly accurate for bubble point determination because it operates according to the synthetic method of phase equilibrium measurements. The results indicate that the solubility of CO in methyl methacrylate has an "inverse" temperature-dependence in which larger amounts of gas can dissolve in the liquid as temperature is increased at a fixed pressure. A comparison to carbon dioxide solubility in the same liquid shows that CO dissolved much less than CO2 in methyl methacrylate. The solubilities of these two gases differed up to about one order of magnitude. (C) 2012 Elsevier B.V. All rights reserved

De produktie van mierezuur door direkte hydrolyse van methylformiaat

Document uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science

Bubble-point pressures of binary and ternary mixtures of acetaldehyde with Versatic 10 and Veova 10

No literature data are available on the phase behavior of binary or ternary systems involving acetaldehyde, Versatic 10, and Veova 10. This experimental study presents bubble point curves within a temperature range of 295–350 K for the two binaries of acetaldehyde + Versatic 10 and acetaldehyde + Veova 10 at several concentrations. Bubble point data are also presented for the ternary system acetaldehyde + Versatic 10 + Veova 10. The Cailletet equipment was used for the measurements, which operates according to the synthetic method. The measured bubble point pressures increased with increasing temperature and reached up to 3 bar within the concentration and temperature range investigated

Vapor-liquid equilibria of binary mixtures of propylene oxide with either ethyl benzene, 2-methylpentane, or 2-methyl-1-pentene

In this experimental investigation, the bubble points of three binary mixtures consisting of propylene oxide + ethyl benzene, propylene oxide + 2-methylpentane, and propylene oxide + 2-methyl-1-pentene were determined. The method of experimentation was the synthetic method in which phase change for a mixture of constant overall composition is observed visually by varying pressure at constant temperature. Each binary system was measured for a range of concentrations. Temperatures and pressures also varied from 323 K to 373 K and up to 5 bar, respectively. It is observed that the solubility of propylene oxide varies, in increasing order, in 2-methylpentane, 2-methyl-1-pentene, and ethyl benzene, with the solubility being far greater in ethyl benzene compared to either 2-methylpentane or 2-methyl-1-pentene. (C) 2013 Published by Elsevier B.V

Effect of the ethoxy groups distribution on the phase behavior of the binary systems carbon dioxide (CO2) + industrial non-ionic surfactants (CiEOj)

Solubility experiments of industrial ethoxylated surfactants denoted as CiEOj (where Ci = hydrocarbon tail, EOj = oxyethylene groups, i = 6–8 and j = 3–5) in sub-and supercritical carbon dioxide were carried out at different temperatures, pressures and concentrations in a Cailletet apparatus as a representative model for dry cleaning system. For the study, industrial surfactants with an ethoxy group distribution were used to replicate the actual dry-cleaning process. For a variety of compositions, results are reported for binary systems within temperature and pressure ranges of 260–310 K and 2.0–10 MPa respectively. In each experiment the surfactants reach equilibrium with carbon dioxide at different concentrations. The data show that with all the surfactants upon increasing concentration, the liquid–liquid curve shifts to lower temperatures. Therefore, the one-phase solution gap is reduced in pressure and temperature at higher concentrations. When the length of the hydrocarbon tail remains constant and the ethoxylated chain is increased from three to five groups, the LL curve once again shifts to lower temperatures and the two phases start earlier. This effect can be attributed to the higher surfactant’s polarity due to the increase in j. On the other hand, when the number of ethoxylated group’s j remains constant and the length of the hydrocarbon tail is increased from six to eight carbon atoms, there is also a significant shift in the LL curve. That signals the fact that the appearance of two phases is also related with the length of the hydrocarbon chain and therefore the surfactant structure itself. These results differ from the trend presented for the pure surfactants in CO2 and can be attributed to the ethoxy group distribution of the industrial type surfactant

Solubility of ethylene in methyl propionate

In this work, the solubility of ethylene in methyl propionate was measured within a temperature range of 283.5–464.8 K and pressures up to 10.7 MPa. Experiments were carried out using the Cailletet apparatus, which uses a synthetic method for the experiments. The critical points of several isopleths have also been determined experimentally for this system. The Peng–Robinson equation of state was used to predict the solubility of ethylene in methyl propionate. The absolute average deviation for all of the calculated points was 5.8%

Bubble point pressures of binary system of methanol and methyl propionate

In this work, bubble point pressures of the system of methanol + methyl propionate were measured for several isopleths within temperature and pressure ranges of 382-444 K and 0.437-2.285 MPa, respectively. The vapor pressures of pure methanol and methyl propionate were also measured. The two-suffix Margules equation was used to represent the nonidealities of the liquid phase and the virial equation of state was used to take into account the nonidealities of the vapor phase. The temperature-dependent parameter of the two-suffix Margules equation was determined using Barker's method. The results show that the model can successfully estimate the bubble points of this system with average errors less than 0.69%

High pressure phase behavior of methanol + ethylene : experimental measurements and CPA modeling

High pressure–temperature isopleths were obtained, experimentally, for the binary system of methanol + ethylene within a temperature and pressure range of 293–373 K and 38–119 bar, respectively. The experimental results were modeled using the Cubic-Plus-Association (CPA), Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state. The ability of the CPA model to predict the phase behavior of methanol + ethylene is much better than the SRK and PR models. However, even though the p–T diagrams indicate that the CPA equation of state correlates well with the experimental results, by increasing ethylene concentrations, the errors of CPA increase due to the solvation that occurs in methanol + ethylene systems. In this work, the effect of solvation is also investigated. Results show that deviations from experimental data are less for CPA with solvation than for the CPA without solvation. Correlations are presented for the binary interaction (kij) and the association volume (ßAiBj) parameters to model the phase behavior of methanol + ethylene, as both of these parameters were indicated to be temperature-dependent

High-pressure vapor-liquid equilibria of methanol + propylene : experimental and modelling with SAFT

The high-pressure vapor–liquid equilibria of methanol + propylene was measured experimentally within a temperature and pressure range of 293–373 K and 0.17–3.7 MPa, respectively, using a synthetic method. The system showed a highly non-ideal behavior with positive deviation from Raoult's law. The phase behavior was also modeled by the statistical associating fluid theory (SAFT) and the Soave–Redlich–Kwong (SRK) equations of state. The statistical associating fluid theory correlated the phase behavior of the binary system much better than the Soave–Redlich–Kwong model, especially at higher pressures. For example, the average absolute deviation percent (AAD%) at T = 370 K was 1.11% for the SAFT model with k12 = 0.02088 and 6.75% for the SRK model with k12 = 0.0803