A study on the pyrolysis of alkylbenzenes in relation to the thermal stability of jet fuels.

摘要

This study is undertaken to obtain a greater understanding of pyrolytic behavior of alkylbenzenes that might be present in jet fuels or among the products of thermally stressing jet fuels.;n-Alkylbenzenes react similarly during pyrolysis in major reaction products, pathways of their formation, reaction kinetics and solid-forming tendencies. Five major products, toluene, (n-1) 1-alkene, styrene, (n-2) n-alkane and ethylbenzene, are formed as a result of ;Branching has significantly influenced pathways of pyrolysis and solid formation behaviors. Although rates of solid formation are largely similar for the three isomers of butylbenzenes with different side chain configurations (s-BB, i-BB and t-BB), different induction periods are needed. The order of solid formation is s-BB ;Heavy fractions of the liquid products appear to be very similar in structures and consist mainly of three to five ring compounds. Major PAHs formed in the liquid products are naphthalene, terphenyls, phenanthrene, biphenyl, and their methylated counterparts. They are probably formed through diene synthesis, alkylation/cyclization and arylation through phenyl radicals. Cyclization/dehydrogenation reactions of diphenylalkanes may also be one of the processes that produce PAHs. The generation of PAHs by various types of reactions constitutes important hydrogen-donating reactions responsible for the production of hydrogen-rich small molecular weight compounds.;Effects of adding styrene to n-butylbenzene and t-butylbenzene are different. Styrene does not change the pathways of n-butylbenzene pyrolysis and PAH formation are promoted. Styrene exhibits inhibitive behavior in the pyrolysis of t-butylbenzene.