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 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.

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.

Induced infrared spectra of H2 adsorbed on alkali halide surfaces: separation of ortho- and para-H2 by desorption

1995 ◽  
Vol 331-333 ◽  
pp. 1473-1478 ◽  
Author(s):  
J. Heidberg ◽  
N. Gushanskaya ◽  
O. Schönekäs ◽  
R. Schwarte
Keyword(s):  
Infrared Spectra ◽  
Alkali Halide

Binary common-ion alkali halide mixtures thermodynamic analysis of solid-liquid phase diagrams

Calphad ◽  
1983 ◽  
Vol 7 (3) ◽  
pp. 211-218 ◽  
Author(s):  
Harry A.J. Oonk ◽  
Jacobus G. Blok ◽  
Joke A. Bouwstra
Keyword(s):  
Liquid Phase ◽  
Phase Diagrams ◽  
Thermodynamic Analysis ◽  
Alkali Halide ◽  
Common Ion ◽  
Solid Liquid

O-Methylation of phenolic compounds with dimethyl carbonate under solid/liquid phase transfer system

2002 ◽  
Vol 43 (14) ◽  
pp. 2661-2663 ◽  
Author(s):  
Samedy Ouk ◽  
Sophie Thiebaud ◽  
Elisabeth Borredon ◽  
Pierre Legars ◽  
Loı̈c Lecomte
Keyword(s):  
Phenolic Compounds ◽  
Liquid Phase ◽  
Dimethyl Carbonate ◽  
Phase Transfer ◽  
Transfer System ◽  
Solid Liquid
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