THE HYDROGEN ISOTOPE EFFECT IN THE PYROLYSIS OF ETHYL-1,1,2,2-d4 ACETATE

Abstract

The hydrogen isotope effect in the pyrolysis of ethyl-1,1,2,2-d4 acetate has been measured in the temperature range 442–650 °C. Making allowance for symmetry numbers in the formation of the ethylene products C2D4 and C2D3H, the isotope effect may be expressed as[Formula: see text]The data are interpreted as indicating a reaction co-ordinate in which a C—H bond is breaking, but contributions to the isotope effect from residual C—H and (or) incipient O—H vibrations, and from bending vibrations, must be included to explain the results satisfactorily.