Rare Earth Metals Ion-exchanged β-Zeolites as Supports of Platinum Catalysts for Hydroisomerization of n-Heptane

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• 作者：Ping LIU^a ; Yue YAO^a ; Xingguang ZHANG^a ; Jun WANG ; ^a ; ^{junwang@njut.edu.cn"" rel=""nofollow}
• 关键词：hydroisomerization of n-heptane ; &#x3b2 ; -zeolite ; bifunctional catalyst ; Ce ; La
• 刊名：Chinese Journal of Chemical Engineering
• 出版年：2011
• 出版时间：April 2011
• 年：2011
• 卷：19
• 期：2
• 页码：278-284
• 全文大小：306 K

文摘

A series of Pt catalysts supported on the Hβ-zeolite that is ion-exchanged with the rare earth metal ions of Ce(III) and La(III), are prepared by impregnation, characterized by inductively coupled plasma (ICP), X-ray diffraction (XRD), BET, temperature-programmed desorption of ammonia (NH₃-TPD), temperature-programmed reduction of hydrogen (H₂-TPR) and H₂-chemisorption techniques, and evaluated in the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor. The reaction temperature, time on stream, space velocity, and the ratio of H₂/n-heptane are changed to get the optimal conditions. The Ce(III) and La(III)-exchanged Hβ-zeolites exhibit higher selectivity for isomerized products than the neat Hβ-zeolite. Moreover, the Ce(III)-exchanged catalysts give higher conversions of n-heptane, whereas the La(III)-exchanged ones do not show any improvement in conversion. Under optimal conditions, the catalyst with 0.4 % (by mass) Pt and 0.5 % (by mass) Ce loading presents very high selectivity of isomerized products of 95.1 % coupled with high n-heptane conversion of 68.7 % . Effects of the ion-exchange of Ce(III) and La(III) on the catalytic performance are discussed in relation with the physicochemical properties of catalysts.