Propionaldehyde, photolysis

In setting up this discussion let us consider one particular photochemical decomposition, the photolysis of propionaldehyde. A review of the experimental data is not the purpose of this analysis, but rather we shall take a simplified mechanism and use deductions from this mechanism to define terms and to establish ideas. 

In the photolysis of propionaldehyde the molecular split (2) occurs to some extent, but the principal mode of decomposition is into two radicals, CaHs and HCO. The subsequent discussion is concerned only with the radicals and their reactions. Either radical could, in general, abstract a hydrogen from the reactant or any hydrogen-containing product. 

The cross section for photolysis of propionaldehyde may again be taken to be... 

Aliphatic Carbonyl Compounds.—The photodissociation of formaldehyde, acetone, acetaldehyde, and propionaldehyde was studied by Solomon, Jonah, Chandra, and Bersohn, using the photolysis mapping technique. " For each molecule, broadband excitation in the (/> -> n ) band led to an anisotropic distribution of the... 

Terentis, A.C., P.T. Knepp, and S.H. Kable (1995), Nascent state distribution of the HCO photoproduct arising from the 309 nm photolysis of propionaldehyde, J. Phys. Chem., 99, 12704-12710. 

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