424. The thermal decomposition of tetrafluorethylene

Abstract

The thermal decomposition of tetrafluoroethylene at temperatures from 309" to 890" is described. Below 600" dimerization to octafluorocyclobutane, and the reverse reaction, are much faster than any of the other reactions taking place. Hexafluoropropene and octafluorobutenes are formed a t 600-800". A t 800" hexafluoroethane and tars are also obtained. Vapour-pressure measurements for the major products are reported.

Infrared multiphoton dissociation of two perfluorobutenes

“…The isomerization of octafluoro-1-butene to octafluoro-2-butene or vice versa would confirm that fluorine migration takes place prior to dissociation in these large fluorocarbon systems. In addition, the elimination of CF 4 from either of these compounds would support the hypothesis that C 2 F 4 polymerizes to a four carbon species before decomposing to produce CF 4 .…”

“…From the IRMPD experiments, no evidence of the direct elimination of CF 4 was observed. Rather, the predominant reaction process in these compounds is CF 3 loss.…”

“…It is possible that CF 4 can be formed if CF 3 abstracts a fluorine atom from another species such as the fluorinated allyl radical. If the reaction of two C 2 F 4 molecules can produce CF 4 and CF 2 CCF 2 the subsequent reaction of C 2 F 4 and CF 2 CCF 2 could produce CF 4 and CF 2 CCCF 2 . In this manner a carbon chain or network could be produced.…”

“…C 2 F 4 pyrolysis may produce the perfluorobutenes octafluoro-1-butene and octafluoro-2-butene among other products. 4 CF 4 elimination from the pyrolysis of one or both of these compounds could explain the C 2 F 4 combustion products. The purpose of this study is to investigate these two perfluorobutenes by IRMPD coupled with photofragment translational spectroscopy to determine the primary reaction products.…”

“…The primary products in an infrared multiphoton dissociation ͑IRMPD͒ experiment are identical to the products from thermal decomposition. 1 IRMPD experiments on hexafluoropropene have been described previously, 2 and the major primary decomposition products were CF 2 , CF 3 , C 2 F 3 , and C 2 F 4 .…”