Reactions of Free Radicals with Aldehydes. The Reactions of Methyl and t-Butoxy Radicals with Acetaldehyde and Acrolein

The reaction in the gas phase of radicals derived from the thermal decomposition of di-t-butyl peroxide with acetaldehyde and acrolein has been studied. The activation energy for H atom abstraction from acetaldehyde by methyl was found to be 7.5±0.3 kcal/mole. The steric factor was about 3.7×10−3, in agreement with many similar reactions. Evidence for chain ending steps other than the recombination of methyl radicals is given. Acrolein polymerizes as well as decomposes in the presence of radicals. The polymerization follows the kinetics to be expected from chain propagation by radical-monomer interaction and chain termination by radical combination. Evidence that the decomposition may be the splitting off of carbon monoxide from the polymerizing chain is presented.