Pyrolysis of Furan and Its Methylated Derivatives: A Shock-Tube/TOF-MS and Modeling Study.

In this study, the pyrolysis of furan (F) and its two methyl-substituted derivatives 2-methylfuran (2-MF) and 2,5-dimethylfuran (2,5-DMF) was investigated behind reflected shock waves at pressures near 1 bar in Ne as the bath gas. Concentration-time profiles of different stable species (reactants, intermediates, and products) were recorded simultaneously with high-repetition time-of-flight mass spectrometry and compared to results from simulations with a recently published, combined F/2-MF/2,5-DMF oxidation mechanism that was slightly modified already in another publication to describe the formation of H atoms in these pyrolysis systems. The temperature ranges covered in our experiments were chosen in line with the different thermal stabilities of the three reactants (F: T = 1050-1920 K; 2-MF: T = 1060-1900 K; 2,5-DMF: T = 1000-1800 K). In general, we obtained satisfactory agreement of the experimental and modeling results. To clarify the most important reaction routes for the formation of the detected species, we performed extensive sensitivity and rate-of-production analyses. The influence of increasing methylation of the furan ring on the formation and consumption of the different species is discussed in detail. Experimental concentration-time profiles are given in tabular form in the Supporting Information to enable tests of future mechanism developments.