scholarly journals Thermal Tautomerism of Crotonic Acid and Vinylacetic Acid, Neat and in Heavy Water

1971 ◽  
Vol 49 (23) ◽  
pp. 3807-3814 ◽  
Author(s):  
Martin B. Hocking
Keyword(s):  
Heavy Water ◽  
Crotonic Acid ◽  
Vinylacetic Acid

A distillate containing 25% vinylacetic acid has been obtained from trans-crotonic acid. Pure vinylacetic acid has been obtained from this by successive thermal equilibrations and distillations. Vinylacetic acid has been subjected to tautomerization conditions in acidic, neutral, and basic media, the latter in normal and in heavy water. These observations are coordinated in an attempt to arrive at plausible pathways for the various transformations observed.

The Effect of Heat on cis- and trans-Crotonic Acids: Alternatives to Direct cis–trans Isomerism

1972 ◽  
Vol 50 (8) ◽  
pp. 1224-1232 ◽  
Author(s):  
M. B. Hocking
Keyword(s):  
Initial Component ◽  
Crotonic Acid ◽  
Trans Acid ◽  
Vinylacetic Acid ◽  
Cis And Trans

The thermal cis–trans equilibration of cis- and trans-crotonic acids (2-butenoic acids) has been examined at temperatures in the range 100–189°. The trans acid has been found to yield a mixture of at least five components, of which 9–11.6% was cis-crotonic acid, and 19.4–31.7% was a dimer of trans-crotonic acid. Heating cis-crotonic acid yielded similar final mixtures, but with an initial component of vinylacetic acid, not seen in the trans acid equilibrations. The rates of formation and identities of the components formed in these two sets of experiments, together with data for the thermal tautomerization of vinylacetic acid, are discussed with reference to suggested pathways for these transformations.

Calculation of Equilibrium Constant for Dimerization of Heavy Water Molecules in Saturated Vapor

2015 ◽  
Vol 60 (3) ◽  
pp. 263-267
Author(s):  
L.A. Bulavin ◽  
◽  
S.V. Khrapatyi ◽  
V.M. Makhlaichuk ◽  
Keyword(s):  
Equilibrium Constant ◽  
Heavy Water ◽  
Saturated Vapor ◽  
Water Molecules

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

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