During the process of pyrolysis of chlorodifluormethane, trifluoromethane and hexafluoropropylene oxide in the presence of supporters, like activated carbon (AC) and porous aluminum fluoride (PAF), no tetrafluoroethene (TFE) was detected at early time-on-stream (TOS), and some compounds containing CF3 group were generated instead of the formation of TFE. The pyrolysis process is much different from that without supporters. It is proposed that the disproportionation reaction of CF2 carbene may take place on the surface of supporters to produce CF3 radical and carbon. (C) 2009 Elsevier B.V. All rights reserved.