THE FORMATION AND OXIDATION OF AROMATICS IN CYCLOPENTENE AND METHYL-CYCLOPENTADIENE MIXTURES

摘要

Aromatic hydrocarbon formation and oxidation is discussed in the context of detailed chemical kinetic modeling of cyclopentene flames and methyl-cyclopentadiene pyrolysis in a shock tube. The main objective is to explore the relative roles of cyclopentadienyl- and phenyl radical-based sequences leading to the formation of naphthalene and indene in a system featuring a high cyclopentadienyl to phenyl radical ratio. The work is also motivated by a desire to explore the importance of possible linkages between cyclopen-tadiene/benzene and indene/naphthalene through CH_3 or ~1CH_2/~3CH_2 addition reactions. Naphthalene formation is considered in the context of a number of tentative detailed sequences that include C_8H_5 + C_2H_2, C_8H_5 + C_4H_4, and C_7H_7 + C_3H_3 routes as well as initiation via C_5H_5 + C_5H_5. It is shown that that a fast cyclopentadienyl-based recombination route is not consistent with experimentally determined naphthalene concentrations under the conditions considered. The study lends support to the suggestion that the addition of CH_3 to C_5H_5 is a viable path for benzene formation. Attention is also placed on paths leading to different isomeric C_9H_8 structures, and it is shown that steps such as C_6H_5 + C_3H_3 have the potential to explain indene formation with good quantitative accuracy. The study further suggests that an important route to naphthalene formation is initiated via acetylene addition to the ethenylphenyl radical.