Thermal Decomposition of Ketene in Shock Waves

Abstract

Abstract With the use of a single pulse shock tube of a magic hole type, the thermal decomposition of ketene was studied at temperatures from 1140 to 1530°K. The formation of carbon monoxide, that is, the disappearance of ketene, followed a kinetic order of 1.5 with respect to ketene and its rate constant was represented by k=10^14.2exp[(-65600±1100)/RT]l^1/2mol^-1/2sec^-1. The thermal decomposition of mixtures of ketene and ethylene in argon was also studied, and the formation of methylene radicals during the pyrolysis of ketene is deduced from the presence of propylene and cyclo-propane in the products of these three component reactants. The rate of ketene disappearance was not affected by the addition of ethylene, or nitric oxide. A chain mechanism in which methylene radicals play a principal part, and a combined molecular mechanism of first, and second orders were proposed tentatively to explain the observed 1.5th order reaction rate.