THE SECONDARY HYDROGEN ISOTOPE EFFECTS IN THE PYROLYSIS OF ETHYL- d 5 ACETATE AND ETHYL ACETATE- d 3

Abstract

Rate constant expressions have been obtained for ethyl acetate and ethyl-d 5 acetate in the temperature ranges 500–603 °C and 501–614 °C.[Formula: see text]By measuring the relative rate of production of C 2 H 4 and C 2 D 4 from identical mixtures of the two esters at the temperatures 387 and 490 °C, it has been possible to determine the temperature coefficient of the relative rate constant more accurately. This, coupled with the relative rate constants at 500 °C derived from the above equations, gives the relative rate constant expression.[Formula: see text]These data are compared with the intramolecular isotope effect in the decomposition of ethyl-1,1,2,2-d 4 acetate, and the differences attributed to secondary isotope effects.The rate of decomposition of ethyl acetate-d 3 was found to be identical within experimental error with that of the normal acetate.