Very low pressure pyrolysis of furan, 2-methylfuran and 2,5-dimethylfuran. The stability of the furan ring

Furan (F), 2-methylfuran (MF), and 2,5-dimethylfuran (DMF) decompose between 1050 and 1270 K by ring breakdown unimolecular reactions. Loss of carbon monoxide is either the exclusive process or a major one in the case of F and MF or DMF decompositions, respectively. A common mechanism involving skeletal isomerization of the furans via cyclopropenylcarbonyl intermediates competing with decomposition through stabilized biradicals is proposed. The analysis of kinetic data leads to similar overall activation parameters for the three furans.