Thermal cracking of n-butylbenzene at high pressure: Experimental study and kinetic modelling

Abstract

The main products are toluene, ethylbenzene, iso-heptyl-and iso-butylbenzene, CH4 and C2H6.  A detailed kinetic model was constructed and validated over the entire experimental range of conversion (0.7-62%).  Thermochemical and kinetic parameters of key decomposition routes were computed using theoretical calculations.

Influence of H2S on the thermal cracking of alkylbenzenes at high pressure (70 MPa) and moderate temperature (583–623 K)

“…The hydrocarbons produced by the pyrolysis of n-butylbenzene/H 2 S mixture are globally the same than those obtained by the pyrolysis of pure n-butylbenzene [24]: short alkylbenzenes (toluene, ethylbenzene), branched alkylbenzenes (iso-butylbenzenes, iso-heptylbenzenes), alkenylbenzenes (styrene, butenylbenzenes), gaseous products (from methane to butane) and methylindane. Typical gas chromatograms obtained for gaseous and liquid products can be seen in [24].…”

“…The significantly lower value of E a in comparison to pure n-butylbenzene thus characterizes: 1) the global acceleration effect of H 2 S on nbutylbenzene cracking, despite the lower value of A which decreases the rate constant to a lower extent than the increase due to the relatively low value of E a 2) the higher acceleration effect of H 2 S at 583 K than at 623 K. The comparison of the pyrolysis product distributions between the n-butylbenzene/H 2 S mixture and pure n-butylbenzene [24] focuses on hydrocarbons. As highlighted above, the hydrocarbons produced by the pyrolysis of n-butylbenzene/H 2 S mixture are globally the same than those obtained by the pyrolysis of pure n-butylbenzene [24]. The major differences are the yields X i , which are expressed by Eq.…”

“…The pyrolysis products of the n-butylbenzene/H 2 S mixture were quantified by Thermodesorption-GC-FID using the method described in [24]. The gold tubes were desorbed at 523 K inside a sealed piercing device under vacuum.…”

“…The conversion of n-butylbenzene in mixture with H 2 S is compared to the conversion of pure nbutylbenzene [24] (Fig. 2).…”

“…The alkyl side chain is long enough to allow the possible production of polycyclic compound. A previous published paper presented the experimental results and the construction of the detailed kinetic model of the pyrolysis of pure n-butylbenzene [24]. Here the pyrolysis of the n-butylbenzene/H 2 S (80% : 20% mol) mixture is investigated at 70 MPa and in the range 583-623 K. The detailed results, i.e.…”