Photolysis of diethylketone in presence of nitric oxide and of nitrogen dioxide

Abstract

The initial rate of formation of nitrogen dioxide which is produced when diethylketone is photolyzed in presence of nitric oxide is given, for constant incident light intensity, by d[NO₂]/dt=k[NO]²[RCOR].^½ The rate decreases with temperature, the apparent activation energy being –23 kJ mole^–1. The reaction is attributed to the disproportionation of nitric oxide by the unstable intermediate C₂H₅CONO. The disproportionation is inhibited by nitrogen dioxide; it is estimated that the propionyl radical reacts about ten times as rapidly with nitrogen dioxide as with nitric oxide. Kinetic parameters for the system are similar to those found for the analogous reactions in the acetone system. An attempt was made to identify the products of the chain-ending step, 2RCONO → products.