Mechanism for isomerization of n-hexane over sulfated zirconia: role of hydrogen

Isomerisation of n-hexane over sulphated zirconia modified by noble metals

“…We observe negative reaction orders in hydrogen, and positive orders in the hydrocarbon, again in agreement with some previous reports [27][28][29]. However, in the literature a wide range of kinetic orders have been reported [5,11,17,19,21,[30][31][32][33][34]. Some of the differences observed can be explained by differences in the pressure, since the reaction rate is reported to pass through a maximum with increasing pressure [11,[32][33][34].…”

“…However, in the literature a wide range of kinetic orders have been reported [5,11,17,19,21,[30][31][32][33][34]. Some of the differences observed can be explained by differences in the pressure, since the reaction rate is reported to pass through a maximum with increasing pressure [11,[32][33][34].…”

Membrane reactors for the dehydrogenation of alkanes to alkenes

“…Because it was impossible to analyze the carbonaceous product online and the quantity was assumed to be less, C 0 was not taken into account in calculating the conversion. Such a decrease in the conversion with time can be understood to be due to a decrease in the catalytic activity including carbon deposition, suggesting that hydrogen is necessary to maintain the activity, as reported in the literature (Duchet et al, 1999;Ebitani et al, 1991;Zhang et al, 1995). Hydrogen separation was never carried out during the first five runs, and then was done with increasing the flow rate of sweep gas in two steps.…”

“…Because the 2MP/3MP ratio is near 2, the isomerization via the cyclic mechanism rather than the bond-shift mechanism is considered to be predominant (Duchet et al, 1999;Shinoda et al, 2000), and therefore hydrogen can be produced mostly according to the cyclization as the initial step of n-hexane isomerization as follows: n-C 6 H 14 /C 5 H 9 À CH 3 ðMCPÞ þ H 2 (16.4)…”

Effects of Hydrogen Removal on the Catalytic Reforming of n-Hexane in a Palladium Membrane Reactor

“…It is well-known that hydrogen has some effects on the reforming rate of paraffin, which increases with increasing partial pressure of hydrogen, p H . [4][5][6][7][8] Also, the rate is found to decrease slowly with increasing p H after reaching a maximum. 9,10 Such a p H dependency has been successfully explained by a rate expression derived on the basis of an acidic mechanism on Lewis sites.…”