Deactivation of External Acid Sites of H-Mordenite by Modification with Lanthanide Oxides for the Isopropylation of Biphenyl and the Cracking of 1,3,5-Triisopropylbenzene and Cumene

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• 作者：Chokkalingam Anand ; Ikuyo Toyama ; Hiroshi Tamada ; Shogo Tawada ; Satoshi Noda ; Ken-ichi Komura ; Yoshihiro Kubota ; Se Woong Lee ; Sung Jung Cho ; Jong-Ho Kim ; Gon Seo ; Ajayan Vinu ; Yoshihiro Sugi
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：September 26, 2012
• 年：2012
• 卷：51
• 期：38
• 页码：12214-12221
• 全文大小：385K
• 年卷期：v.51,no.38(September 26, 2012)
• ISSN：1520-5045

文摘

The modification of H-mordenite (MOR) with lanthanide oxides La₂O₃, CeO₂, Pr₂O₃, Sm₂O₃, Dy₂O₃, and Yb₂O₃ was examined for the deactivation of external acid sites and confirmed in the cracking of 1,3,5-triisopropylbenzene (TIPB) and cumene (IPB) and in the isopropylation of biphenyl (BP). The cracking of TIPB, which cannot enter the pores of MOR, shows that external acid sites were effectively deactivated by the modification of MOR with the lanthanide oxides in small amounts. Only the cracking of IPB over CeO₂-modified MOR exhibited excellent catalytic activities, even at a 30 wt % metal loading, whereas the activities of other lanthanide oxide-modified MORs rapidly decreased as the loadings were increased because pore entrances became choked. The isomerization of 4,4鈥?diisopropylbiphenyl (4,4鈥?DIPB) during the isopropylation of BP at high temperatures such as 300 掳C was also effectively prevented by the modification of MOR with the lanthanide oxides. Particularly, CeO₂-modified MOR remained highly active even at a 30 wt % loading. Other lanthanide oxides can deactivate the isomerization of 4,4鈥?DIPB at 5鈥?0 wt % loadings without significant loss of the activities at 300 掳C, while the activity was rapidly lost as the loading amount was increased. The physicochemical properties of lanthanide oxide-modified MORs indicate that the lanthanide oxides modify the surface properties of MOR. The amounts of N₂, o-xylene, and NH₃ adsorbed on MORs mostly remained high after CeO₂ modification; however, they rapidly decreased when loadings of the other oxides increased. These results show that CeO₂ remains the open pores at high loadings; however, the other oxides reduce the size of pore entrances as the loading is increased.