Xylene isomers Sample Clauses

Xylene isomers. The very first study about xylene isomers was reported by Barnard and Xxxxxx in 1968 (47,48), who investigated the oxidation of the three xylene isomers in the temperature range 733 to 785 K in a conventional static reactor. They observed that ortho-xylene possessed a much greater degree of reactivity towards oxygen than its isomers meta- and para-xylene. Following this first work, as shown in Tables 5 and 6, xylene combustion has been investigated extensively. Xxxxx et al. (49,50) investigated the oxidation of the three isomers in an atmospheric flow reactor at temperatures between 1093 and 1199 K. Using GC, they detected xylylene and recommended it as the source of the higher reactivity of o-xylene due to its fast isomerization to styrene. More recently, the pyrolysis ortho-xylene was studied by Xxxx et al. (51) using a flow reactor at pressures 0.04-1 atm and temperatures 1050-1600 K, confirming the presence of xylene through SVUV-PIMS analysis. The oxidation of the three xylene isomers was studied in a jet-stirred reactor by Gail et al. (52–54) between 900 and 1400 K, at 10 bar. The highest reactivity was observed for ortho-xylene and products quantified by GC included CO, CO2, CH2O, CH4, C2H2, C2H4, C2H6, xxxxxx, propyne, C3H6, acrolein, 1,3-C4H6, vinylacetylene, 1,3-cyclopentadiene, benzaldehyde (as shown in figure 2). A detailed kinetic model was proposed for each isomer. In 2021, this work was completed by a study made at 10 bar between 800 and 1200 K for ortho- xylene by Xxxx et al. (51), who proposed a detailed model based on their previous ones for aromatic compounds and consisting of 415 species and 2726 reactions. No JSR measurement below 800 K is available, not even for ortho-xylene for which low temperature reactivity might be expected. Figure 2: Oxidation of ortho-xylene in a JSR at 1 atm and Φ = 0.5. The initial conditions were 0.10% fuel 2.10% O2, 97.80% N2 in mole; τ = 0.1 s. Experimental data (symbols) are compared to computations (lines and small symbols) (54). In 2000, Xxxxxxx et al. (55,56) used a rapid compression machine to measure the auto-ignition delay times of a series of arenes, including xylene isomers, in the temperature region 600-900 K, at compressed pressures up to 25 bar. They observed that toluene, meta-xylene, para-xylene, and 1,3,5-trimethylbenzene ignited only above 900 K and 16 atm, while ortho-xylene, 1,2,3-trimethylbenzene and 1,2,4-trimethylbenzene ignited at much lower temperatures and pressures. They concluded ...