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Effect of substituents in the gas‐phase elimination kinetics of β‐substituted ethyl acetates
Author(s) -
Chuchani Gabriel,
Martin Ignacio,
Avila Irama
Publication year - 1979
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550110602
Subject(s) - chemistry , steric effects , arrhenius equation , methyl acetate , kinetics , acetic acid , alkyl , arrhenius plot , reaction rate constant , medicinal chemistry , atmospheric temperature range , torr , ethyl acetate , gas phase , butyl acetate , organic chemistry , thermodynamics , activation energy , physics , quantum mechanics , solvent
Abstract The kinetics of gas‐phase elimination of 3‐methyl‐1‐butyl acetate and 3,3‐dimethyl‐1‐butyl acetate into acetic acid and the corresponding substituted butenes have been measured over the temperature range of 360–420°C and the pressure range of 63–250 Torr. The reactions are homogeneous in both clean and seasoned vessels, obey first‐order law, and are unimolecular. The temperature dependence of the rate constants is given by the Arrhenius equation 3‐methyl‐1‐butyl acetate:\documentclass{article}\pagestyle{empty}\begin{document}$$ {log k(sec}^{{ - 1}} {) = (12}{.73 } \pm { 0}{.29) - (202}{.5 } \pm { 3}{.8) kJ/mol/2}{.303}RT $$\end{document}3,3‐dimethyl‐1‐butyl acetate:\documentclass{article}\pagestyle{empty}\begin{document}$$ {log k(sec}^{{ - 1}} {) = (12}{.34 } \pm { 0}{.35) - (194}{.1 } \pm { 4}{.2) kJ/mol/2}{.303}RT $$\end{document}The points in a plot of log ( k / k 0 ) of β‐alkyl and several β‐substituted ethyl acetates against E s values appear aligned in an approximate linear relationship. These results may be interpreted as a consequence of steric effects, namely, steric accelerations.