Table of Contents
Laser Chemistry
Volume 5, Issue 5, Pages 257-273
http://dx.doi.org/10.1155/LC.5.257

Generation of Ketene With High Quantum Yield by a KrF Laser

1Max-Planck-lnstitut für Quantenoptik, Garching 8046, Germany
2Dept. of Modern Chemistry, Univ. of Science and Technology, Hefei, (Anhui), China

Received 20 December 1984; Accepted 22 February 1985

Copyright © 1985 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Acetone was photolyzed around 770 K by pulsed laser irradiation at 248 nm. The methyl radicals, generated in the primary step, trigger a chain reaction, producing ketene (CH2CO) and methane. Long chains (high quantum yields) result from low radical concentrations. Using a collimated laser beam of low intensity, quantum yields up to 300 have been demonstrated. Approximate rate constants have been derived and used for extrapolation to higher temperatures and different densities. Compared to the thermal process, the photochemical formation of ketene is faster. Therefore its thermal decomposition can be avoided to some extent. But the improvement is probably too small to be of technical interest. We also found indications that the thermal decomposition of acetone above about 500 to 600 K yields three fragments in a single step.