Thermal Decomposition of N-Methylpyrrole: Experimental and Modeling Study

Article abstract of DOI:10.1021/j100119a031

The thermal decomposition of N-methylpyrrole was studied behind reflected shocks in a pressurized driver single pulse shock tube over the temperature range 1050-1300 K at overall densities of ca. 3 x 10^-5 mol/cm³.A large number of decomposition products with and without bound nitrogen were obtained under shock heating.High concentrations of isomerization (2- and 3-methylpyrrole) ans six-membered ring compounds (pyridine) were also found.The main decomposition channel is initiated by a rupture of the N-CH3 bond with a rate constant of initiation , where R is expressed in units of cal/(K mol).Abstraction reactions and recombination of methyl radicals lead to the production of a line of hydrocarbons such as CH4, C2H6, and C2H4.Abstraction of a hydrogen atom from the N-CH3 group leads to the production of C4H4N-CH2<*> which upon ring enlargement produces pyridine.Toluene was used as a free radical scavenger to distinguish between radical chains and unimolecular processes.Reaction products such as CH3CN are obtained by a unimolecular decomposition of the N-methylpyrrole ring.The total decomposition of N-methylpyrrole in terms of a first-order rate constant is given by .First-order Arrhenius rate parameters for the formation of the various reaction products are given, a reaction scheme is suggested, and results of computer simulation and sensitivity analysis are shown.Differences and similarities in the reactions of pyrrole and N-methylpyrrole are discussed.