The Vibrational Spectra and Structure of Dimethyl Carbonate and its Conformational Behavior

1975 ◽  
Vol 53 (9) ◽  
pp. 1378-1386 ◽  
Author(s):  
J. E. Katon ◽  
M. D. Cohen
Keyword(s):  
Liquid Phase ◽  
Infrared Spectra ◽  
Dimethyl Carbonate ◽  
Solid Phase ◽  
Equilibrium Mixture ◽  
Vibrational Assignment ◽  
Enthalpy Difference ◽  
Oriented Polycrystalline ◽  
Phase Data ◽  
Liquid And Solid Phases

The infrared spectra of dimethyl carbonate in the liquid and solid phases and the Raman spectrum of the liquid phase are reported. The evidence suggests that dimethyl carbonate exists as an equilibrium mixture of at least two conformers in the liquid state. An experimental value for the enthalpy difference of the two conformers of 2.6 ± 0.5 kcal/mol is obtained from the temperature dependency of the infrared spectrum.Dimethyl carbonate crystallizes as an oriented polycrystalline film and polarized infrared spectra of the solid have been obtained. These have been utilized, along with the liquid phase data to obtain an improved vibrational assignment. There appears to be a solid–solid phase change in dimethyl carbonate in the vicinity of 140 K, but the details of this change are not known.

Conformational Isomerism and Oriented Polycrystal Formation of Dimethyl Carbonate

1974 ◽  
Vol 52 (10) ◽  
pp. 1994-1996 ◽  
Author(s):  
J. E. Katon ◽  
Mark D. Cohen
Keyword(s):  
Liquid Phase ◽  
Infrared Spectra ◽  
Alkali Halide ◽  
Dimethyl Carbonate ◽  
Conformational Equilibrium ◽  
Equilibrium Mixture ◽  
Polycrystalline Film ◽  
Conformational Isomerism ◽  
Enthalpy Difference ◽  
Oriented Polycrystalline

It has been found that dimethyl carbonate exists in the liquid phase as a conformational equilibrium mixture. The conformers differ by rotation about the C—O bonds. The enthalpy difference of the two conformers is found experimentally to be 2.6 ± 0.5 kcal/mol. Dimethyl carbonate crystallizes in contact with alkali halide windows as an oriented polycrystalline film, as shown by polarized infrared spectra.

The Vibrational Spectra of α-Bromoacetaldehyde Dimethyl Acetal and Related Molecules

1975 ◽  
Vol 29 (6) ◽  
pp. 501-506 ◽  
Author(s):  
J. E. Katon ◽  
Philip D. Miller
Keyword(s):  
Liquid Phase ◽  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Low Temperatures ◽  
Conformational Equilibrium ◽  
Dimethyl Acetal ◽  
Vibrational Assignment ◽  
Crystal State ◽  
Apparent Evidence

The complete vibrational spectra of α-bromoacetaldehyde dimethyl acetal and α-bromoacetaldehyde dimethyl s6 have been recorded on the pure liquids, and a tentative vibrational assignment has been proposed. The infrared spectra of both compounds in the crystal state have also been recorded at low temperatures. There is no apparent evidence of a conformational equilibrium in the liquid phase. The infrared spectra of three other acetals have been recorded, and the data from all of the compounds are discussed in terms of previously proposed group frequencies of acetals in both the infrared and Raman.

scholarly journals Solid-liquid phase equilibria of (H2O-Mn(H2PO2)2-MnCl2-NaCl), (H2O-Mn(H2PO2)2-MnCl2) and (H2O-NaCl- MnCl2) systems at 323.15 K

2020 ◽  
pp. 59-59
Author(s):  
Vedat Adiguzel ◽  
Wei Liu ◽  
Asadullah Memon ◽  
Hongtao Zhou ◽  
Imran Akbar ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Phase Equilibria ◽  
Quaternary System ◽  
Invariant Point ◽  
Solid Phase ◽  
Ternary Systems ◽  
Invariant Curves ◽  
Saturation Method ◽  
Solid Liquid ◽  
Liquid And Solid Phases

The solid-liquid phase equilibria (SLE) and densities of H2O-NaCl- -MnCl2-Mn(H2PO2)2 quaternary system, H2O-NaCl-MnCl2 and H2O-MnCl2- -Mn(H2PO2)2 ternary systems were investigated at 323.15 K by the isothermal solution saturation method. The analyses of the liquid and solid phases were used to determine the composition of the solid phase using the Schreinemakers graphic method. The ternary systems contain one invariant point, two invariant curves and two crystallization regions. In the quaternary system, there is one invariant point, three invariant curves, and three crystallization areas corresponding to NaCl, MnCl2 4H2O, and Mn(H2PO2)2H2O. The crystallization area of Mn(H2PO2)2 H2O, being the largest in comparison with those of other salts, occupied 80.75 % of the total crystallization area.

scholarly journals Application of equilibrium phase diagrams for calculation of segregation kinetics during two-component melt cooling

2020 ◽  
Vol 63 (2) ◽  
pp. 129-134
Author(s):  
A. D. Drozin ◽  
E. Yu. Kurkina
Keyword(s):  
Liquid Phase ◽  
Equilibrium State ◽  
Cross Section ◽  
Diffusion Coefficients ◽  
Solid Phase ◽  
Equilibrium Phase ◽  
Minimum Size ◽  
Two Component ◽  
Solid Phases ◽  
Liquid And Solid Phases

According to the equilibrium state diagrams, when the melt is cooled to a certain temperature below liquidus, compositions of liquid and solid phases are uniquely determined by corresponding curves in the diagram. However, it does not happen in reality. For equilibrium (which the diagram describes), it is necessary that the melt is maintained indefinitely at each temperature, or thermal conductivity of liquid and solid phases, and the diffusion coefficients of their components, are infinitely large. We made an attempt to find out how these processes occur in reality. In this work, we consider the growth of individual crystal during cooling of a two-component melt. Mathematical model is constructed based on the following. 1. The melt area with volume corresponding to one grain, the periphery of which is cooled according to a certain law, is considered. 2. At the initial instant of time, a crystal nucleus of a certain minimum size is in the liquid. 3. At the surface of crystal, compositions of liquid and solid phases correspond to equilibrium state diagram at a given temperature on its surface. 4. Changes in temperature and composition in liquid and solid phases occur according to the laws of heat conduction and diffusion, respectively. As the melt gets cold and the crystal grows, the liquid phase is enriched in one component and depleted in another, the solid phase – on the contrary. Since the diffusion coefficients of the components in the solid phase are small, the composition of the crystal does not have time to completely equalize its cross section. The model proposed in the work allows us to study this phenomenon, to calculate for each cooling mode how the composition of the crystal will vary over its cross section. The calculations have shown that the temperature equalization occurs almost instantly, and composition of the liquid phase equalizes much slower. Equalization of the solid phase composition does not occur in the foreseeable time. The results of the work will help to improve technology of generation of alloys with an optimal structure.

scholarly journals Solid-liquid phase equilibria in the ternary systems H2O+ZnCl2+NaCl at temperatures of 298, 313 and 333 K

2021 ◽  
pp. 53-53
Author(s):  
Sevilay Demirci ◽  
Vedat Adiguze ◽  
Omer Sahin
Keyword(s):  
Liquid Phase ◽  
Phase Equilibria ◽  
Solid Phase ◽  
Ternary Systems ◽  
Viscosity Data ◽  
Isothermal Method ◽  
Chloride Water ◽  
Solid Phases ◽  
Solid Liquid ◽  
Liquid And Solid Phases

In this study, an economic separation method was suggested with the use of phase equilibria in order to ensure the recycling of ZnCl2 whose industrial waste amount is very high and to prevent it to form an environmental pollution. Sodium chloride-zinc chloride-water systems were examined with the isothermal method at temperatures of 298, 313 and 333 K. The analyses of the liquid and solid phases were used to determine the composition of the solid phase using the Schreinemakers graphic method. The solid-liquid phase equilibrium and viscosity data belonging to all ternary systems were identified and the solubility and viscosity changes with temperature were compared. The viscosity values were inversely proportional to the temperature as the amount of ZnCl2 in the solution increased. NaCl, 2NaCl ZnCl2 nH2O (n: 2, 0), ZnCl2 salts were observed at 298, 313, 333 K in the solid phases which are at equilibrium with the liquid phase at the invariant point.

Infrared and Raman spectra and vibrational assignment of methylene cyclopropane-h6 and -d6

1970 ◽  
Vol 48 (24) ◽  
pp. 3889-3902 ◽  
Author(s):  
J. E. Bertie ◽  
M. G. Norton
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Raman Spectra ◽  
Infrared Spectra ◽  
Infrared And Raman Spectra ◽  
Vibrational Assignment ◽  
Isotope Shifts ◽  
Liquid Phases ◽  
Modes Of Vibration ◽  
Depolarization Ratios

Infrared spectra have been recorded in the range 4000 to 20 cm−1 for methylene cyclopropane-h6 and -d6 in the gas phase, and from 4000 to 200 cm−1 for methylene cyclopropane-h6 in the liquid phase. Raman spectra have been recorded for the liquid phases of both species. The fundamental modes of vibration have been assigned using i.r. band contours and Raman depolarization ratios, with the exception of the i.r. inactive A2 modes which were not observed. An interesting feature is the occurrence of remarkably small isotope shifts for certain modes.

The Vibrational Spectra of Methyl Cyanoacetate and Methyl Cyanoacetate-d3

1974 ◽  
Vol 52 (17) ◽  
pp. 3057-3062 ◽  
Author(s):  
Deepali Sinha ◽  
J. E. Katon
Keyword(s):  
Liquid Phase ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Vibrational Assignment ◽  
Conformational Isomers ◽  
Solid Phases ◽  
Liquid And Solid Phases

The i.r. spectra of methyl cyanoacetate in both liquid and solid phases and of methyl cyanoacetate-d3 in the liquid phase have been recorded in the region 4000–250 cm−1. The Raman spectra of both the compounds in the liquid phase have also been recorded. A tentative vibrational assignment has been made both for the light and the heavy ester. Evidence is presented for the existence of conformational isomers in the liquid phase.

scholarly journals A Computational Method for The Computer Simulation of The Liquid Phase Sintering of Metallic Systems

2020 ◽  
Author(s):  
Hamed Hosseinzadeh
Keyword(s):  
Liquid Phase ◽  
Binary Phase Diagram ◽  
Solid Phase ◽  
Liquid Phase Sintering ◽  
Solid Particles ◽  
Computational Method ◽  
Sintering Process ◽  
Composition Variation ◽  
Liquid And Solid Phases ◽  
Oswald Ripening

The growth of solid particles during liquid phase sintering was modeled by the Cellular Automata method. The binary phase diagram and Fickian approach for the diffusion process were applied to simulate the chemical composition variation in liquid and solid phases during sintering. The Oswald-Ripening effect was considered during the dissolution of the solid phase in the liquid phase. It is used to define the probability of solid-phase dissolution by the liquid phase and develop the model to simulate the alloy with solid solubility. So, the microstructure could be modeled in the liquid phase sintering process.

Identification of hepatitis a virus in cell cultures by solid phase immune electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 238-239
Author(s):  
C.D. Humphrey ◽  
T.L. Cromeans ◽  
E.H. Cook ◽  
D.W. Bradley
Keyword(s):  
Electron Microscopy ◽  
Liquid Phase ◽  
Cell Cultures ◽  
Rapid Detection ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Immune Electron Microscopy ◽  
Detection And Identification

There is a variety of methods available for the rapid detection and identification of viruses by electron microscopy as described in several reviews. The predominant techniques are classified as direct electron microscopy (DEM), immune electron microscopy (IEM), liquid phase immune electron microscopy (LPIEM) and solid phase immune electron microscopy (SPIEM). Each technique has inherent strengths and weaknesses. However, in recent years, the most progress for identifying viruses has been realized by the utilization of SPIEM.

SYNTHESIS OF HYDROGEN IN ACOUSTOPLASMA DISCHARGE IN A LIQUID-PHASE STREAM

2019 ◽  
pp. 42-48 ◽  
Author(s):  
N. A. Bulychev
Keyword(s):  
Liquid Phase ◽  
Organic Compounds ◽  
Electrode Materials ◽  
Solid Phase ◽  
Plasma Discharge ◽  
Raw Material ◽  
Two Phase ◽  
Reduced Pressure ◽  
External Power Source ◽  
Phase Medium

In this paper, the plasma discharge in a high-pressure fluid stream in order to produce gaseous hydrogen was studied. Methods and equipment have been developed for the excitation of a plasma discharge in a stream of liquid medium. The fluid flow under excessive pressure is directed to a hydrodynamic emitter located at the reactor inlet where a supersonic two-phase vapor-liquid flow under reduced pressure is formed in the liquid due to the pressure drop and decrease in the flow enthalpy. Electrodes are located in the reactor where an electric field is created using an external power source (the strength of the field exceeds the breakdown threshold of this two-phase medium) leading to theinitiation of a low-temperature glow quasi-stationary plasma discharge.A theoretical estimation of the parameters of this type of discharge has been carried out. It is shown that the lowtemperature plasma initiated under the flow conditions of a liquid-phase medium in the discharge gap between the electrodes can effectively decompose the hydrogen-containing molecules of organic compounds in a liquid with the formation of gaseous products where the content of hydrogen is more than 90%. In the process simulation, theoretical calculations of the voltage and discharge current were also made which are in good agreement with the experimental data. The reaction unit used in the experiments was of a volume of 50 ml and reaction capacity appeared to be about 1.5 liters of hydrogen per minute when using a mixture of oxygen-containing organic compounds as a raw material. During their decomposition in plasma, solid-phase products are also formed in insignificant amounts: carbon nanoparticles and oxide nanoparticles of discharge electrode materials.

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