University of North Carolina at Asheville
Subject Listing - Chemistry
Advisor: Dr. Bert Holmes
Friday, Oral Session 4, Presentation 3, Karpen Hall 038
EXPERIMENTAL UNIMOLECULAR RATE CONSTANTS FOR 2,3-HF AND 2,3-HCl ELIMINATION FROM CF3CFClCH2Cl
Chlorofluorocarbons are one class of chemical substance that depletes the ozone layer. Because of their deleterious effect on stratospheric ozone, the production of CFCs is being phased out and other organic molecules are being introduced as substituents. Hydrochlorofluorocarbons (HCFCs) are one class of compounds under consideration as a replacement because they are similar to CFCs but are not as destructive to ozone.
The present work studied chemically activated HCFC, CF3CFClCH2Cl, which was formed in the gas phase from the combination of CF3CFCl and CH2Cl radicals. The radicals were generated from the ultraviolet photolysis of the corresponding iodides using a high pressure Hg lamp. The decomposition products were E- and Z-CF3CCl=CHCl from a 2,3-FH elimination and E- and Z-CF3CF=CHCl from a 2,3-HCl elimination reaction. Unimolecular rate constants for CF3CFClCH2Cl were 3.6 x 103 s-1 and 6 x 102 s-1 for 2,3-HF elimination forming E- and Z- products, respectively, and 2.3 x 104 s-1 and 6.5 x 103 s-1 for 2,3-HCl elimination to form the E- and Z- products, respectively. No evidence was found for a 1,2-FCl interchange reaction.
Advisor: Dr. Bert Holmes, Carson Distinguished Professor in the Sciences, Department of Chemistry, University of North Carolina at Asheville, Asheville, NC