Photoöxidation of Butene-1 and Isobutene by Nitrogen Dioxide

Reactions of oxygen atoms, produced by photolysis of nitrogen dioxide at 3660 Å, with butene-1 and isobutene have been studied at room temperature. In the case of butene-1, α-butene oxide and n-butanal have been identified as the major products, and methyl ethyl ketone, propanal, acetaldehyde, and ethyl nitrate as minor products. With isobutene, isobutanal was recovered as the major product and acetone, methyl ethyl ketone, methyl nitrate, and nitromethane as minor products. The absence of isobutene oxide in the recovered products from the isobutene reaction is due to its rapid reaction with nitrogen dioxide.The following values were obtained for the relative reaction rates of oxygen atoms with nitrogen dioxide (k2), butene-1 (k4a), and isobutene (k4b): k2/k4a = 1.9, k2/k4b = 0.34, k4b/k4a = 5.5.