Catalytic dehydrogenation of ethylbenzene with carbon dioxide: promotional effect of antimony in supported vanadium–antimony oxide catalyst

Ethylbenzene Dehydrogenation in the Presence of Carbon Dioxide over Metal Oxides

“…al., 2003) and others (Badstube et al, 1998;Dziembaj et al, 2000), for instance, have investigated iron oxide catalysts promoted with alkali metals supported on alumina and charcoal, respectively, for ethylbenzene dehydrogenation, noting the increased selectivity to the products in the presence of carbon dioxide. Also, the use of carbon dioxide have been studied on iron oxide supported on zirconium oxide and zeolites Chang et al, 2004), vanadium oxide catalysts and vanadium-antimony supported on alumina (Vislovskiy et al, 2002;Park et al, 2003), in which there was the increased catalytic activity, according to the catalyst. From these studies, they have observed that the effect of carbon dioxide on the activity, selectivity and stability for ethylbenzene dehydrogenation depends on the kind of the catalyst.…”

Dehydrogenation of Ethylbenzene with Carbon Dioxide as Oxidant over Mg-modified Alumina-supported V–Sb Oxide Catalysts

“…ported VO x species whereas the presence of SbO x positively affects the catalyst stability through the facilitation of the redox cycle. 12,13 Moreover, it is noted that the Mg-containing catalysts studied exhibit much stable catalytic behavior compared to the VSb/Al (Figure 1). When we checked the content of carbon formation on each catalyst after 12 h on stream, we observed that Mg-modified catalysts reveal less carbon formation (4.4-6.0 wt %) as compared with VSb/Al (13.1 wt %), indicating that modification of alumina support with magnesia leads to the stable activity, at least partly, due to strong resistance against carbon formation.…”

“…However, taking into account no detectable phase of vanadium oxide in XRD, a catalytically active V-component appears to be well dispersed on the support materials. It was found that XRD peaks of VSbO 4 -like phases, which are well detectable in the VSb/Al 12,13 and VSb/Mg 0:1 Al catalysts, are very weak in the VSb/Mg 0:3 Al and, moreover, they fully disappear in the VSb/Mg 0:5 Al catalyst. This result implies the stronger interaction between acidic V-Sb oxide and Mg n Al support materials while using a large content of basic MgO in catalyst preparation.…”

“…[1][2][3] Several families of the catalysts, mainly based on supported or mixed oxides of Fe, V, or Cr were found to be active and selective in the CO 2 -EBDH. [2][3][4][5][6][7][8][9][10][11][12][13][14] However, most of the catalysts have usually shown strong deactivation for this reaction during even a few hours on stream. As a typical example, over Mg-Al-V mixed oxides, the initial styrene yield, 64% after 1 h on stream, decreased to 40% after 7 h. 7 The similar deactivation rate was observed also for VO x /MgO catalyst.…”

“…3 We have proposed a very active and selective catalyst, V 0:43 Sb 0:57 O x / Al 2 O 3 (VSb/Al), but its deactivation was also significant mainly owing to coke formation although the deactivation rate was less than other reported catalysts. 12,13 Since the coke precursors are easily formed through the oligomerization of olefins, facilitation of olefins desorption from a catalyst surface could minimize the carbon accumulation. Taking into consideration a basic character of electron-rich olefins including styrene, lower surface acidity of the catalyst appears to induce easier desorption of olefins from the catalyst surface.…”