Carbon formation in flames,

In fact, such polymerization reactions may play an important role in carbon formation in flames (26). 

In 1892, Lewes (13, 14, 66) first proposed that acetylene is an important intermediate in combustion processes. He suggested a theory of luminosity of flames based upon its formation and subsequent incandescent decomposition. This did not prove successful as a general explanation of luminosity, but in recent years a modified version of this concept has been advocated by Porter (58, 59) and others. They suggest that acetylene is the starting point for the major reactions of carbon formation in flames and combustion. 

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