MOLECULAR STRUCTURE AND PHOTOCHEMICAL REACTIVITY .14. VAPOR-PHASE PHOTOCHEMISTRY OF TRANS-CROTONALDEHYDE

The vapor-phase photochemistry of trans-crotonaldehyde has been studied at wavelengths longer than 2550 Å between 70 and 130°. The major photodecomposition products were CO and propylene. Small amounts of C2H4, allene, methylacetylene, cyclopropane, ethylketene, and enol-crotonaldehyde were also formed. The results are explained by a mechanism involving decomposition from, and multistage collisional deactivation of, a vibrationaly excited upper singlet state, intersystem crossing to an unstable upper triplet state, and internal conversion to the ground state via isomerization of the upper singlet state to unstable intermediates. © 1969, American Chemical Society. All rights reserved.