AUTHOR=Watanabe Ryo , Ikushima Maiko , Mukawa Kei , Sumomozawa Fumitaka , Ogo Shuhei , Sekine Yasushi 

TITLE=Lanthanoid-free perovskite oxide catalyst for dehydrogenation of ethylbenzene working with redox mechanism

JOURNAL=Frontiers in Chemistry

VOLUME=1

YEAR=2013

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2013.00021

DOI=10.3389/fchem.2013.00021

ISSN=2296-2646

ABSTRACT=<p>For the development of highly active and robust catalysts for dehydrogenation of ethylbenzene (EBDH) to produce styrene; an important monomer for polystyrene production, perovskite-type oxides were applied to the reaction. Controlling the mobility of lattice oxygen by changing the structure of Ba<sub>1 − <italic>x</italic></sub>Sr<sub>x</sub>Fe<sub><italic>y</italic></sub>Mn<sub>1 − <italic>y</italic></sub>O<sub>3 − δ</sub> (0 ≤ <italic>x</italic> ≤ 1, 0.2 ≤ <italic>y</italic> ≤ 0.8), perovskite catalyst showed higher activity and stability on EBDH. The optimized Ba/Sr and Fe/Mn molar ratios were 0.4/0.6 and 0.6/0.4, respectively. Comparison of the dehydrogenation activity of Ba<sub>0.4</sub>Sr<sub>0.6</sub>Fe<sub>0.6</sub>Mn<sub>0.4</sub>O<sub>3 − δ</sub> catalyst with that of an industrial potassium promoted iron (Fe–K) catalyst revealed that the Ba<sub>0.4</sub>Sr<sub>0.6</sub>Fe<sub>0.6</sub>Mn<sub>0.4</sub>O<sub>3 − δ</sub> catalyst showed higher initial activity than the industrial Fe–K oxide catalyst. Additionally, the Ba<sub>0.4</sub>Sr<sub>0.6</sub>Fe<sub>0.6</sub>Mn<sub>0.4</sub>O<sub>3 − δ</sub> catalyst showed high activity and stability under severe conditions, even at temperatures as low as 783 K, or at the low steam/EB ratio of 2, while, the Fe–K catalyst showed low activity in such conditions. Comparing reduction profiles of the Ba<sub>0.4</sub>Sr<sub>0.6</sub>Fe<sub>0.6</sub>Mn<sub>0.4</sub>O<sub>3 − δ</sub> and the Fe–K catalysts in a H<sub>2</sub>O/H<sub>2</sub> atmosphere, reduction was suppressed by the presence of H<sub>2</sub>O over the Ba<sub>0.4</sub>Sr<sub>0.6</sub>Fe<sub>0.6</sub>Mn<sub>0.4</sub>O<sub>3 − δ</sub> catalyst while the Fe–K catalyst was reduced. In other words, Ba<sub>0.4</sub>Sr<sub>0.6</sub>Fe<sub>0.6</sub>Mn<sub>0.4</sub>O<sub>3 − δ</sub> catalyst had higher potential for activating the steam than the Fe–K catalyst. The lattice oxygen in perovskite-structure was consumed by H<sub>2</sub>, subsequently the consumed lattice oxygen was regenerated by H<sub>2</sub>O. So the catalytic performance of Ba<sub>0.4</sub>Sr<sub>0.6</sub>Fe<sub>0.6</sub>Mn<sub>0.4</sub>O<sub>3 − δ</sub> was superior to that of Fe–K catalyst thanks to the high redox property of the Ba<sub>0.4</sub>Sr<sub>0.6</sub>Fe<sub>0.6</sub>Mn<sub>0.4</sub>O<sub>3 − δ</sub> perovskite oxide.</p>