Solubility of monocrotaline in supercritical carbon dioxide and carbon dioxide—ethanol mixtures

The solubility of monocrotaline, a chemotherapeutic drug precursor, in supercritical carbon dioxide and carbon dioxide—ethanol mixtures has been measured from 308.15 to 328.15 K and from 8.86 to 27.41 MPa. The solubility ranges from 6.0 × 10⁻⁶ to 2.21 × 10⁻⁴ mol fraction increasing up to 25-fold with the addition of ethanol. A new method for the estimation of the sublimation pressure of monocrotaline was developed based on the measured solubilities of monocrotaline in water. The sublimation pressure was then used in the compressed gas model to correlate the behavior of carbon dioxide—monocrotaline and carbon dioxide—ethanol—monocrotaline systems with reasonable success.     

Vapor—liquid equilibrium studies for the carbon dioxide—methanol system

Experimental vapor—liquid equilibrium measurements of carbon dioxide and methanol have been conducted from 230 K (−43.15°C) to 330 K (56.85°C) at pressures to the very vicinity of the critical states. The consistency of the data sets are examined and compared to literature values.Unlike the methane—methanol system, which exhibits two liquid phases at low temperatures, the carbon dioxide—methanol system exhibits complete liquid phase miscibility. Accordingly, the effects of critical behavior on the vapor liquid equilibria behavior begin to manifest themselves at much lower pressures.     

High-pressure phase equilibria for the carbon dioxide–2-methyl-1-butanol,carbon dioxide–2-methyl-2-butanol,carbon dioxide–2-methyl-1-butanol–water,and carbon dioxide–2-methyl-2-butanol–water systems

High-pressure vapor–liquid equilibria for the binary carbon dioxide–2-methyl-1-butanol and carbon dioxide–2-methyl-2-butanol systems were measured at 313.2 K. The phase equilibrium apparatus used in this work is of the circulation type in which the coexisting phases are recirculated, on-line sampled, and analyzed. The critical pressure and corresponding mole fraction of carbon dioxide for the binary carbon dioxide–2-methyl-1-butanol system at 313.2 K were found to be 8.36 MPa and 0.980, respectively. The critical point of the binary carbon dioxide–2-methyl-2-butanol was also found 8.15 MPa and 0.970 mole fraction of carbon dioxide. In addition, the phase equilibria of the ternary carbon dioxide–2-methyl-1-butanol–water and carbon dioxide–2-methyl-2-butanol–water systems were measured at 313.2 K and several pressures. These ternary systems showed the liquid–liquid–vapor phase behavior over the range of pressure up to their critical point. The binary equilibrium data were all reasonably well correlated with the Redlich–Kwong (RK), Soave–Redlich–Kwong (SRK), Peng–Robinson (PR), and Patel–Teja (PT) equations of state with eight different mixing rules the van der Waals, Panagiotopoulos–Reid (P&R), and six Huron–Vidal type mixing rules with UNIQUAC parameters.     

Molecular simulation of the Joule–Thomson inversion curve of carbon dioxide

The complete Joule–Thomson (JT) inversion curve for carbon dioxide is calculated using molecular simulations. A two center Lennard–Jones model with an embedded point quadrupole is used to model the fluid–fluid interactions. The simulation results agree quantitatively with all available experimental data. Comparison with commonly used equations of state provides only a modest agreement, with the highest discrepancies being observed at the high temperature branch of the inversion curve.     

Solid–liquid equilibria for the dimethyl ether + carbon dioxide binary system

A recently built experimental setup was employed for the estimation of the solid–liquid equilibria of alternative refrigerants systems. The behavior of dimethyl ether (DME) + carbon dioxide was measured down to temperatures of 131.6 K. To confirm the reliability of the apparatus, the triple point of the DME was measured. The triple point data measured revealed a good consistency with the literature. The results obtained for the mixtures were corrected by the Rossini method and interpreted by means of the Schröder equation.     

Nickel–cobalt hydroxide catalysts for the cycloaddition of carbon dioxide to epoxides

Research on Chemical Intermediates - Nickel and cobalt bimetallic hydroxides, in which both metal cations present the same oxidation state, were synthesized and characterized by XRD, TGA, TEM, XPS,...     

Enantioselective addition of carbon acids to α-nitroalkenes: the first asymmetric aminocatalytic reaction in liquefied carbon dioxide

Carbon acids, in particular malonates, malononitrile, and anthranone, react enantioselectively with α-nitroalkenes in the presence of Takemoto’s organocatalyst in liquid carbon dioxide medium (100 bar, rt), under homogeneous conditions, to afford the corresponding Michael adducts in moderate to high yields and with enantioselectivities comparable with those obtained in organic solvents.     

Selective hydrogenation of phenol in supercritical carbon dioxide

Liquid phase hydrogenation of phenol over Pt/C catalysts was investigated under conventional conditions and supercritical carbon dioxide (scCO2). The equivalent ration of hydrogen to phenol shows a significant effect on the product selectivity. Hydrogenation of phenol in different solvents was also studied, the experimental results show that polarity of solvents influences the yield of cyclohexanone remarkably, scCO2 has the highest one. Catalytic hydrogenation of phenol in scCO2 or sub-sc…     

Contribution to the system Europium — boron — carbon

By means of chemical preparation techniques and x-ray analysis the ternary system EuBC was studied, with special emphasis on the technologically important sections EuB₆C and EuB₆B₄C. It was possible to prove the existance of a hexaboride-carbon solid solution EuB_6−xC_x (0 ⩽ x ⩽ 0.25), a ternary phase EuB₂C₂, the europlum carbides EuC_x (⪡Eu₂C⪢), EuC₂, as well as another carbide of the approximate composition Eu₂C₃.     

Solubility measurement of α-asarone in supercritical carbon dioxide

The solubility of α-asarone in supercritical CO₂ (sc-CO₂) has been measured using the dynamic method. The measurement was conducted in the pressure range from 9.0 to 18.0 MPa at temperature 35–49 °C. The experimental data were correlated using the Chrastil model. The results show that the solubility increases as the pressure rises and decreases as the temperature rises, which is well correlated with the Chrastil model.     

High-pressure densities and P–T–x–y diagrams for carbon dioxide+linalool and carbon dioxide+limonene

Liquid and vapor densities for carbon dioxide+linalool, and carbon dioxide+limonene were measured by using a system consisting of two vibrating tube densimeters. The P–T–x–y diagrams and saturated liquid and vapor densities for these two binary mixtures were determined at 313, 323 and 333 K, respectively, as well as at pressures up to 11 MPa. The density of the saturated CO₂ phase increased with increasing pressure. At higher pressure, the density of the liquid phase decreased with increasing pressure, corresponding to an increasing amount of carbon dioxide.     

Reduction of carbon dioxide by hydrogen on metal–carbon catalysts under supercritical conditions

The reduction of carbon dioxide with hydrogen on metal–carbon (Ru, Rh, Ir) catalysts is investigated under supercritical conditions for the first time. High selectivity (close to 100%) toward methanation with good stability of catalytic activity is observed for Ru- and Rh-containing catalyst, while the preferred reduction to CO is observed for Ir/C catalyst.     

Sorption of carbon dioxide by the composite sorbent “potassium carbonate in porous matrix”

Sorption of CO₂ in the presence of water vapor by the K₂CO₃—-Al₂O₃ composite sorbent was studied by IR spectroscopy in situ, X-ray diffraction analysis, and the differentiating dissolution method and reasons for a decrease in its dynamic capacity are given. The samples containing K₂CO₃·1.5H₂O in pores are characterized by the maximal dynamic capacity. A mechanism for CO₂ sorption was proposed, which qualitatively explains the obtained dependence of the capacity on the water content in the composite sorbent. A high dynamic capacity can be maintained by regeneration of the sorbents by water vapor at 170 °N. The capacity of the sorbents decreases during the first 10 sorption—regeneration cycles due to the formation of an inactive phase of potassium aluminum carbonate.     

Theoretical IR spectra of the (2:1) ammonia–carbon dioxide system

IR spectra were calculated for CO₂, ammonia, (2:1) ammonia–CO₂ complex, carbamic acid, and (1:1) ammonia–carbamic acid complex at the B3PW91/6-311++G** level. For the spectra predicted, a potential energy distribution (PED) was calculated to form the basis for the elucidation of experimental IR data.     

Addition of carbon dioxide to epoxides catalyzed by the mixtures of α-amino acids and iodine

Russian Chemical Bulletin - We found a group of available and efficient catalysts for the addition reaction of CO2 to epoxides, which was formed by simple mixing of molecular iodine with...     

An experimental study of three- and four-phase equilibria for isopropanol—water—carbon dioxide mixtures at elevated pressures

Compositions and molar volumes of the three phases in liquid—liquid—gas equilibrium are reported for ternary mixtures of isopropanol, water and CO₂ at elevated pressures and at temperatures of 50 and 60°C. Phase compositions and molar volumes were also obtained for three-phase, liquid—liquid—liquid equilibrium and four-phase, liquid—liquid—liquid—gas equilibrium at 40°C. Gas—liquid and liquid—liquid critical endpoints, which represent pressure bounds on the liquid—liquid—gas region at 60°C, were determined from observations of critical opalescence.The phase behavior exhibited by the isopropanol—water—CO₂ system is quite complex, particularly at conditions near the critical point of CO₂. These conditions are well within the range of operating conditions proposed for supercritical-fluid extraction of organic compounds from water using CO₂. Therefore, the existence of multiple coexisting phases can be an important factor in designing and operating such extraction processes.     

High pressure vapor–liquid equilibrium data for the systems carbon dioxide/2-methyl-1-propanol and carbon dioxide/3-methyl-1-butanol at 288.2, 303.2 and 313.2 K

In this work, we report vapor–liquid equilibrium data for the systems carbon dioxide (CO₂)/iso-butanol and CO₂/iso-pentanol at 288.2, 303.2 and 313.2 K, and for pressures up to the critical point. The interaction parameters for the Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR) equations of state (EOS) that best fit the experimental results are also given.