Kinetics and mechanism of the thermal gas-phase reaction between trifluoromethylhypofluorite, CF3OF, and tetrachloroethene

✍ Scribed by J. Czarnowski

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 368 KB
• Volume: 28
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1996)28:7<489::aid-kin3>3.0.co;2-r

✦ Synopsis

The thermal gas-phase reaction of CF,OF with CCI,CC12 h a s been studied between 313.8 a n d 343 8 K The initial pressure of CF,OF was varied between 10.8 a n d 77.5 torr a n d that of CCI;,CCI, between 3.7 a n d 26 8 torr. CF,OF was always present in excess, varying t h e initial ratio of CF,OF t o that of CCI,CCI, from I 3 t o 10 Three products were formed-CF,OCCI,CCI,F, CCI,FCCI,F, a n d CF30(CC12CC12 ),OCF, The yields of CF30CCI,CCI,F were 98-99.5%. based o n t h e s u m of t h e products The reaction was a homogeneous chain reaction not affected by t h e total pressure In presence of 0, t h e oxidation of CCI,CCI, t o CCI,C(O)CI a n d COCI, occurred The proposed basic reaction s t e p s are: generation of t h e radicals CF,O' a n d CCI,FCCI,' (4) in a biomolecular process between CF.,OF a n d CCI,CCI,. formation of t h e radical CF,OCCI,CCI, ' by addition of CF,O' t o CCI,CCI,, chain generation of CF,O' by abstraction of fluorine a t o m from CF,OF by CF30CCI,CCI, ' (k,), a n d chain termination by recombination of t h e radicals CF,OCCI,CCI, ' The expressions obtained for t h e constants k l a n d k4 a r e k , = 3 16 ? 0.6 X lo7 exp(-15.2 2 1 7 Kcal moI-'/RT) dm' rno1-l s-'; k, = 3.7 2 0.5 X lOqexp(-6.0 ? 1.1 Kcal m o l -' / R T ) d m 3 m o l ~' s -' . 0 1996lohnWileyGSons.Inc.