Influence of Compressed Carbon Dioxide on the Oxidation of Cyclohexane with Hydrogen Peroxide in Acetic Acid

2006 ◽  
Vol 59 (3) ◽  
pp. 225 ◽  
Author(s):  
Liang Gao ◽  
Tao Jiang ◽  
Buxing Han ◽  
Baoning Zong ◽  
Xiaoxin Zhang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Binary System ◽  
Reaction System ◽  
Phase Region ◽  
Phase Behaviour ◽  
Phase System ◽  
Two Phase ◽  
Three Phase

The oxidation of cyclohexane with H2O2 in a compressed CO2/acetic acid binary system was studied at 60.0 and 80.0°C, at pressures up to 18 MPa, and with the zeolite TS-1 as catalyst. The phase behaviour of the reaction system was also observed. There are three fluid phases in the reaction system at lower pressure but two at higher pressures. In the three-phase region the yields of the products, cyclohexanol and cyclohexanone, increase considerably with increasing pressure and reaches a maximum near the phase-separating pressure. CO2 can thus enhance the reaction effectively. However, the effect of pressure on the yield is very limited after the transition to a two-phase system.

Die Aktivitätskoeffizienten des Hg im Indiumamalgam beim Übergang von der festen zur flüssigen Phase / The activity coefficients of hg in in-amalgams at the solid-liquid phase transition

1971 ◽  
Vol 26 (1) ◽  
pp. 150-153 ◽  
Author(s):  
Günter Franck
Keyword(s):  
Vapour Pressure ◽  
Phase Region ◽  
Resonance Absorption ◽  
Mercury Vapour ◽  
Phase System ◽  
Two Phase ◽  
Liquid Phase Transition ◽  
Three Phase ◽  
Solid Liquid ◽  
Good Agreement

Abstract By 2537 Å resonance absorption the temperature dependency of mercury partial pressure of dif­ferent In-amalgams is measured. - The Hg-concentrations of the investigated amalgams are 1.9 - 20 atomic per cent. The temperature interval is 30 -160 °C. In the solid + liquid two-phase region the activity coefficient of mercury is strongly diminuted with growing temperature. For tem­peratures higher than 130 °C the Hg-vapour pressure in the two-phase region falls with growing temperature.With the help of a generalized Clausius-Clapeyron formula for a three phase system with two components the mercury vapour pressure in the liquid + solid two-phase region is calculated. There is a good agreement with our experimental results

Phase Equilibrium of Mg-Nd-Zn System near Mg-Nd Side at 400°C

2016 ◽  
Vol 873 ◽  
pp. 18-22
Author(s):  
Ming Li Huang ◽  
Xue Shen ◽  
Hong Xiao Li
Keyword(s):  
Solid Solution ◽  
Phase Equilibrium ◽  
Ternary Isothermal Section ◽  
Phase Region ◽  
X Ray Diffraction ◽  
Maximum Solubility ◽  
Two Phase ◽  
Solubility Range ◽  
Three Phase ◽  
Equilibrium Alloys

The equilibrium alloys closed to Mg-Nd side in the Mg-rich corner of the Mg-Zn-Nd system at 400°C have been investigated by scanning electron microscopy, electron probe microanalysis and X-ray diffraction. The binary solid solutions Mg12Nd and Mg3Nd with the solubility of Zn have been identified. The maximum solubility of Zn in Mg12Nd is 4.8at%, and Mg12Nd phase can be in equilibrium with Mg solid solution. However, only when the solubility range of Zn in 26at%~32.2at%, Mg3Nd can be in two-phase equilibrium with Mg solid solution. As the results, two two-phase regions as Mg+Mg12Nd and Mg+Mg3Nd and a three-phase region as Mg+Mg12Nd+Mg3Nd in Mg-Nd-Zn ternary isothermal section at 400°C have been identified.

A two-phase system for the clean and high yield synthesis of furylmethane derivatives over –SO3H functionalized ionic liquids

2017 ◽  
Vol 19 (20) ◽  
pp. 4804-4810 ◽  
Author(s):  
S. H. Shinde ◽  
C. V. Rode
Keyword(s):  
Ionic Liquids ◽  
Reaction System ◽  
High Yield ◽  
Phase System ◽  
Phase Reaction ◽  
Two Phase ◽  
Yield Production ◽  
High Yield Production

A new and effective unique two-phase reaction system for the high yield production of tri(furyl)methane from furfural and furan.

Activity coefficients, densities, dipole moments, and surface tensions of the system triethylamine–methylethylketone–water

1981 ◽  
Vol 59 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Alan N. Campbell
Keyword(s):  
Surface Layer ◽  
Dipole Moments ◽  
Phase System ◽  
Constant Composition ◽  
Two Phase ◽  
Three Phase ◽  
Wide Range ◽  
Isothermal System ◽  
Total Composition ◽  
Two Phases

The properties named in the title have been determined by standard methods. Viscosity, molar volume, and orientation polarisation all indicate abnormalities of the nature of association between the components.The most interesting result is that of surface tension which indicates that, in the case of the binary system triethylamine–water, a surface layer of constant composition is formed over a wide range of total composition. When, by a rise in temperature of two or three degrees, this layer becomes unstable, it splits into two phases of different composition. The surface layer may then be instantaneously reformed and so on. A mechanism for the generation of a two-phase system is thus established. The data for the three-phase, isothermal, system are not so convincing, for reasons that are suggested.

Influence of biomass on hydrodynamics of an internal loop airlift reactor

2006 ◽  
Vol 60 (6) ◽  
Author(s):  
M. Juraščík ◽  
M. Hucík ◽  
I. Sikula ◽  
J. Annus ◽  
J. Markoš
Keyword(s):  
Aspergillus Niger ◽  
Gluconic Acid ◽  
Solid Phase ◽  
Biomass Concentration ◽  
Airlift Reactor ◽  
Phase System ◽  
Two Phase ◽  
Experimental Conditions ◽  
Internal Loop ◽  
Three Phase

AbstractThe effect of the biomass presence on the overall circulation velocity, the linear velocities both in the riser and the downcomer and the overall gas hold-up was studied in a three-phase internal loop airlift reactor (ILALR). The measured data were compared with those obtained using a two-phase system (air—water). All experiments were carried out in a 40 dm3 ILALR at six different biomass concentrations (ranging from 0 g dm−3 to 7.5 g dm−3), at a temperature of 30°C, under atmospheric pressure. Air and water were used as the gas and liquid model media, respectively. Pellets of Aspergillus niger produced during the fermentation of glucose to gluconic acid in the ILALR were considered solid phase. In addition, liquid velocities were measured during the fermentation of glucose to gluconic acid using Aspergillus niger. All measurements were performed in a bubble circulation regime. At given experimental conditions the effect of the biomass on the circulation velocities in the ILALR was negligible. However, increasing of the biomass concentration led to lower values of the total gas hold-up.

Non-Uniform Two-Phase Flow of Supercritical Carbon Dioxide Centrifugal Compressor

2020 ◽  
Author(s):  
Wenrui Bao ◽  
Ce Yang ◽  
Li Fu ◽  
Changmao Yang ◽  
Lucheng Ji
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Flow Field ◽  
Centrifugal Compressor ◽  
Static Pressure ◽  
Leading Edge ◽  
Phase Region ◽  
Tip Clearance ◽  
Two Phase ◽  
Supercritical Carbon

Abstract An asymmetric structure of volute in a supercritical carbon dioxide centrifugal compressor induces a non-uniform circumferential distribution of the upstream flow field, which inevitably affects the formation of a two-phase region of carbon dioxide in an impeller. In this work, unsteady simulations for centrifugal compressors were conducted. First, the influence of low static strip induced by low static pressure near volute tongue on the impeller flow field was presented. Then, the non-uniform flow field distribution in the impeller passages and flow characteristics of the passages at the impeller inlet were obtained. Finally, the two-phase regions in the impeller were presented. The results demonstrate that for a centrifugal compressor with volute, the two-phase region appears not only on the suction surface of the leading edge of the blade, but also in some impeller passages, on the pressure surface of the blade near the leading edge, and in the leading edge and mid-chord of tip clearance, under the design conditions. The low static pressure strip induced by the volute leads to a high-speed region in the impeller passages where the temperature and pressure of supercritical carbon dioxide fall below the critical point and carbon dioxide enters the two-phase region. Meanwhile, the static pressure on the blade surface is distorted under the influence of a high-speed region in the passages, resulting in the formation of a two-phase region at the tip clearance. The flow distortion of passages at the impeller inlet results in the appearance of two-phase regions on the both sides of leading edge of the blade. The dryness on the suction side of the blade leading edge and the leading edge of the tip clearance is lower, which indicated that the proportion of liquid-phase carbon dioxide is higher in these two-phase regions.

Two‐Phase System Utilizing Hydrophobic Metal–Organic Frameworks (MOFs) for Photocatalytic Synthesis of Hydrogen Peroxide

2019 ◽  
Vol 131 (16) ◽  
pp. 5456-5460 ◽  
Author(s):  
Yusuke Isaka ◽  
Yudai Kawase ◽  
Yasutaka Kuwahara ◽  
Kohsuke Mori ◽  
Hiromi Yamashita
Keyword(s):  
Hydrogen Peroxide ◽  
Metal Organic Frameworks ◽  
Phase System ◽  
Two Phase ◽  
Metal Organic ◽  
Photocatalytic Synthesis

Rheological and structural studies on heat-induced gelation of concentrated skim milk

1995 ◽  
Vol 62 (2) ◽  
pp. 257-267 ◽  
Author(s):  
Atsumi Tobitani ◽  
Haruyoshi Yamamoto ◽  
Toshiaki Shioya ◽  
Simon B. Ross-Murphy
Keyword(s):  
Phase Diagram ◽  
Laser Light ◽  
Skim Milk ◽  
Phase Region ◽  
Polymer Physics ◽  
Phase Behaviour ◽  
Two Phase ◽  
Effects Of Ph ◽  
Higher Temperature ◽  
Temperature Side

SUMMARYHeat-induced gelation of milk was studied using both rheological and structural techniques. The sample was a conventional skim milk, concentrated with an ultrafiltration membrane, which formed gels when heated at appropriate pH. We investigated some factors that are considered to affect the gelation, such as concentration, pH and rennet treatment. The gelation process was monitored with a high precision oscillatory shear rheometer and the structure of gels was evaluated with quasi-elastic laser light scattering. From these results the gelation and phase separation behaviour were determined. By combining the results for different concentrations a phase diagram was obtained, which indicated that skim milk had a two-phase region on the higher temperature side. The effects of pH and rennet treatment were also evaluated with the aid of this phase diagram. The results were discussed on the basis of concepts of the phase behaviour of polymers, which were successfully developed in polymer physics.

Critical lines and phase equilibria in binary van der Waals mixtures

1980 ◽  
Vol 298 (1442) ◽  
pp. 495-540 ◽  
Keyword(s):  
Phase Equilibria ◽  
Binary Mixtures ◽  
Critical Points ◽  
Van Der Waals ◽  
Coexistence Curve ◽  
Phase Behaviour ◽  
Maximum Temperature ◽  
Phase System ◽  
Two Phase ◽  
Critical Solution Temperatures

The study of phase equilibria is historically one of the most important sources of information about the nature of intermolecular forces in non-electrolyte liquids and their mixtures. Many of the main features of vapour-liquid and liquid-liquid phase behaviour were already well characterized experimentally during the early part of this century, but the theoretical explanation of phase equilibria for a wide variety of substances and over a large range of pressures and temperatures has lagged far behind. This paper presents theoretical studies of phase equilibria in binary mixtures obeying the van der Waals equation, especially liquid-liquid equilibria that can occur at high pressures. The variety of fluid phase behaviour that occurs in binary mixtures can be qualitatively discussed in terms of the changes in thermodynamic properties near critical points. Upper critical solution temperatures (UCSTs) occur when a heterogeneous (two-phase) system becomes a homogeneous (one-phase) system when the temperature is raised. The maximum temperature along the temperature-mole fraction ( T, x ) coexistence curve for constant pressure is the UCST at this pressure. Lower critical solution temperatures (LCSTs) occur when a homogeneous system becomes a two-phase system when the temperature is increased. The LCST is at the minimum of the T, x coexistence curve. Thermodynamic considerations of critical points yield requirements for the curvature of the mixing functions plotted against x .

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