1970
JOHN
F. %. HICKS,JR.,
AND
EWDARD KROCKMALSKI
Vol. 69
colorize aqueous potassium permanganate solution, nor Such a view may be partially rationalized if bond tqould it react with chlorine in direct sunlight. Since both strengths and polarizabilities are determining facstraight-chain and cyclic unsaturated fluorocarbons are known t o be reactive to these reagents? we have concluded tors in such reactions,l0 since the carbon-fluorine bond is one of the strongest single bonds encounthat this pyrolysis product is octafluorocyclobutane. It may be seen from Table I1 that a t a pressure of 5 mm. tered.7,11,12,13 of mercury the product contained a t least 97% of tetraThe suggestion that CZF4 units are selectively fluoroethylene. As the pressure increased, the yield of off the degrading molecule is favored by cracked tetrafluoroethylene decreased and, instead, C3Fe and the possibility of the close energy coupling between C4Fswere formed in increasing proportions. On the other hand, increasing the temperature from the endothermic cleavage reaction and the exo600 t o 700” had only a minor effect on the composition of thermic closing of the double bond to form tetrathe product. fl~oroethy1ene.l~Such close coupling can result TABLE111 in a significant decrease in the energy requirements However, this is not possible EFFECPOF TEMPERATURE ON THE PRODUCTS O F THERMALof this reaction. DEGRADATION O F POLYTETRAFLUOROETHYLENE AT 41 MM. with the cleavage of any other bond unless such Temp., C.
--Weight CzF4
600 700
85.7 82.1
per cent. of productsCaFs ClF8
14.3 17.9
