Original scientific paper

Acid-Catalyzed Hydration of 1-Methylcycloheptene and Methylenecycloheptane. Construction of the Complete Free Energy Profile for Olefin-Alcohol Interconversion in the 1-Methylcycloheptyl System

Y. Chiang ; Department of Chemistry, University of Toronto, Toronto, Ontario M5S 1A1, Canada
A. J. Kresge ; Department of Chemistry, University of Toronto, Toronto, Ontario M5S 1A1, Canada
P. A. Obraztsov ; Department of Chemistry, University of Toronto, Toronto, Ontario M5S 1A1, Canada
J. B. Tobin ; Department of Chemistry, University of Toronto, Toronto, Ontario M5S 1A1, Canada

Abstract

Rates of the reversible hydration of 1-methylcycloheptene (ENDO) to 1- methylcycloheptanol (ROH) and the essentially irreversible hydration of ethylenecycloheptane (EXO) to ROH, plus the position of equilibrium between ENDO and ROH, were determined in concentrated aqueous perchloric acid solution at 25 °C. The results, together with a literature value of the ENDO : EXO equilibrium ratio, allow dissection of the experimental data into hydronium-ion catalytic coefficients for the following individual processes: ENDO-> ROH, *H+ = 102 x 10~3 NT1 s"1; EXO-ROH, *„ + = 3.53 x 1CT3 NT1 s_1; ROH-ENDO, *H+ = 2.17 x lCT5 M'1 s'1, and ROH-EXO, *H+ = 1.01 x 10~6 M-1 s"1. Combination of these results with a previous estimate of the barrier to reaction of tertiary carbocations with water leads to a complete free energy profile for this system.

Keywords

Hrčak ID:

137121

URI

https://hrcak.srce.hr/137121

Publication date:

15.10.1992.

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