Pathways, Kinetics, and Mechanisms for 2-Dodecyl-9,10-dihydrophenanthrene Pyrolysis

Abstract

We pyrolyzed 2-dodecyl-9,10-dihydrophenanthrene (DDPh) in batch microreactors. The reaction conditions included neat pyrolyses between 375−450 °C for times of 15−240 min and also pyrolyses in benzene at 400 °C and 90 min but at different initial DDPh concentrations ranging from 0.0095 to 0.238 mol/L. The disappearance of DDPh followed first-order kinetics, and the global first-order rate constant had Arrhenius parameters of (log10 A (s-1) = 13.6 ± 2.8 and E (kcal/mol) = 54.5 ± 9.1, where the uncertainties are the 95% confidence intervals. The decomposition of DDPh can be described by a reaction network that possesses four parallel primary pathways. The major primary path, which involves dehydrogenation, leads to 2-dodecylphenanthrene. The other three primary paths involve C−C bond cleavage, and they lead to 2-methyl-9,10-dihydrophenanthrene plus undecene, to 2-vinyl-9,10-dihydrophenanthrene plus decane, and to numerous minor products. Important secondary and tertiary reactions include the rapid reduction ...