Experimental and kinetic modeling study of benzyl alcohol pyrolysis

The pyrolysis of benzyl alcohol (A1CH(2)OH) at 30 and 760 torr was studied in a flow tube reactor. The synchrotron radiation photoionization and molecular-beam mass spectrometry (MBMS) techniques were used to identify and quantify 35 intermediates and products including some small species, several monophenyl ring species, and a large number of polyaromatic hydrocarbons (PAHs). A comprehensive chemical kinetic reaction model involving 376 species and 2171 reactions was developed with reasonable prediction. According to the rate-of-production analysis, the consumption of A1CH(2) OH is mainly proceeded with the H-abstraction reactions with H atoms and OH radicals under both pressures. H-abstractions and unimolecular dissociation dehydrogenation reactions also play important roles in the subsequent formation of PAHs. Phenyl radicals, benzene (A1), and benzyl (A1CH(2)) radicals are important intermediates in the pyrolysis of A1CH(2) OH, which provide various ways for the formation of PAHs. Sensitivity analysis presents that the most significant sensitive reaction of A1CH(2) OH consumption is the unimolecular initiation reaction by the C-O bond breaking from A1CH(2) OH under both pressures. The combination of A1CH(2) radicals with H atoms to form toluene (A1CH(3)) has the most inhibiting influence on the A1CH(2) OH consumption under both pressures, while it has little sensitive effects for the oxidation process of A1CH(2)OH consumption. The comparison of the A1CH(2) OH pyrolysis and oxidation results show that the peak mole fractions of Al increase, while the peak mole fractions of phenol (A1OH) decrease with the increase of equivalence ratio (phi) under the same pressure. It should be noted that the peak mole fractions of benzaldehyde (A1CHO) are relatively stable with various conditions. These results provide a theoretical basis for further study of the combustion chemical kinetics of A1CH(2)OH and its application in bio alternative fuel. (C) 2021 The Combustion Institute. Published by Elsevier Inc. All rights reserved.