CO2 LASER-INDUCED DECOMPOSITION OF PROPAN-2-OL, BUTAN-2-OL, PENTAN-2-OL, PENTAN-3-OL, AND HEXAN-2-OL

The pulsed CO2 laser-induced decompositions of propan-2-ol, butan-2-ol , pentan-2-ol, pentan-3-ol, and hexan-2-ol in the gas phase have been investigated. Like ethanol which we examined previously [1] the absorp tion cross section of propan-2-ol for pulsed 9R14 radiation increases with pressure at low pressures, an effect attributed to rotational hol e-filling. In contrast the absorption cross section of butan-2-ol (10R 24) has only a small pressure dependence and those of pentan-2-ol (9R2 6), pentan-3-ol (10R14), and hexan-2-ol (9P20) show little or no varia tion with pressure in the range 0.1-5.0 torr. Decomposition products h ave been investigated at low pressure where the excitation of the alka nols was essentially collision free. The observed products for all the alkanols can be rationalized on the basis of primary dehydration and C-C fission channels, with minor contributions from other molecular el iminations. (C) 1994 John Wiley and Sons, Inc.