Mg–V–Al mixed oxides with mesoporous properties using layered double hydroxides as precursors: catalytic behavior for the process of ethylbenzene dehydrogenation to styrene under a carbon dioxide flow

CO2 as an Oxidant for High-Temperature Reactions

“…By substituting vanadium in Mg-Al hydrotalcite catalysts, the Mg-V-Al mixed oxides with high surface area and mesoporous characteristics were produced, and found to be favorable for the ethylbenzene dehydrogenation to styrene under CO 2 flow (Carja et al, 2003). Moreover, V 5+ was identified to be the active site for the dehydrogenation process (Carja et al, 2003). The major properties of this catalyst are the weak Lewis acid sites contributed by aluminum, which reduce the catalyst deactivation, in addition to its high surface area contributed by the mesoporous characteristics.…”

Promoting effect of carbon dioxide on the dehydrogenation of ethylbenzene over silica-supported vanadium catalysts

“…High valence vanadium species (V 5+ ) should be the active sites for EB dehydrogenation , while the reduced species (V 4+ and V 3+ ) are less active [15,17]. CO 2 is effective to keep/regain the high valence vanadium species in VO x /SiO 2 , which can then enhance its activity for EB dehydrogen ation.…”

“…Various catalysts containing Fe [5][6][7][8][9][10][11], Cr [12,13], and V [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] were found to be active for EB dehydrogen ation in CO 2 . Among these catalysts, the supported vanadium catalysts showed good performanc e in EB dehydrogen ation.…”

Deshidrogenación catalítica del etilbenceno a estireno

“…Para ello se prepara una solución de dichas especies y por modificación de alguna propiedad (como el pH) se provoca la precipitación conjunta de los distintos componentes en la proporción que interese (Droguett, 1983). Suele utilizarse para la preparación de compuestos con actividad catalítica como óxidos simples o mixtos, sulfuros, carbonatos, fosfatos y una gran variedad de soportes, lo cual podemos observar en los trabajos con catalizadores a base de hierro (Mimura, 2000;Mimura, 2008;Kus-troswki, 2001;Bispo, 2002;Carja, 2003;Ohishi, 2005;Balasamy, 2010), manganeso (Burri, 2006;Balasamy, 2010;), circonio (Burri, 2006Li, 2009), vanadio (Sun, 2004Carja, 2008;Nederlof, 2011), cobre (Freire, 2009Balasamy, 2010), níquel (Freire, 2009;Balasamy, 2010; y cinc (Balasamy, 2010), entre otros.…”

“…La característica principal de la espectroscopía IR reside en permitir identificar especies químicas a través de la determinación de la frecuencia (número de ondas) a la que los distintos grupos funcionales presentan bandas de absorción en el espectro FT-IR (Ferretto, 2002;Nestervenko, 2003;Conceicao y Rangel, 2003;Carja, 2003;Ponomoreva, 2004;Kustrowski, 2005;Bethelo, 2008;Freire, 2009;Li, 2009;. Además, la intensidad de estas bandas puede utilizarse para determinar la concentración de estas especies en la muestra.…”