Hydrogen abstraction from neopentane by methyl radicals

Abstract

The reaction, CD₃+ Me₄C → CD₃H + Me₃CCH₂(1), has been re-investigated by the photolysis of hexadeuterioacetone in the presence of neopentane. Between 185 and 309° the rate constant was found from log k₁(mole^–1 ml. sec.^–1)= 12·3 –(12,000/2·3RT). The Arrhenius parameters are in good agreement with results of other hydrogen abstractions by methyl radicals from alkanes, obtained by the same method. The activation energy obeys the Polanyi relation, E= 0·49 [D(C–H)– 74·3] on the basis of D(Me₃CCH₂–H)= 99 kcal. mole^–1.