Photolysis of Ketene‐Oxygen Mixtures between 253 K and 323 K in Relation to the Formation of Criegee Intermediates

Ketene was photolyzed in a flow reactor in Ar/O 2 = 80/20 carrier gas between 253 and 323 K. Products observed by matrix‐isolation FTIR spectroscopy were CO, CO 2 , O 3 , HCHO, HCOOH, and CH 3 C(O)OC(O)H, formic‐acetic anhydride. Addition of HCHO did not produce hydroxymethyl formate, CH 2 (OH)OCHO, a product expected from the reaction of the stabilized Criegee intermediate H 2 COO with HCHO. Photolysis in the presence of a large excess of water vapour did not change the product pattern. It was concluded that no stabilized Criegee intermediates were formed under the experimental conditions.