Transformation of ethylbenzene-m-xylene feed over MCM-22 zeolites with different acidities

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• 作者：Magdolna R. Mih&aacute ; lyi^a ; ^{mihalyi.magdolna@ttk.mta.hu" class="auth_mail} ; M&aacute ; rton Koll&aacute ; r^a ; Szilvia Klé ; bert^a ; Vesselina Mavrodinova^b
• 关键词：Dealuminated and B-substituted zeolite MCM-22 ; Pt/H-MCM-22 ; Ethylbenzene  ; +  ; m-xylene mixture transformation
• 刊名：Applied Catalysis A: General
• 出版年：22 April, 2014
• 年：2014
• 卷：476
• 期：Complete
• 页码：19-25
• 全文大小：875 K

文摘

Transformation of ethylbenzene (EB, 22 wt%)-m-xylene (78 wt%) mixture was carried out over zeolite MCM-22 catalysts with different acidities. The modification of the number and strength of the acid sites was attained by: (i) dealumination by steaming and successive acid treatment and (ii) isomorphous substitution of framework Al for boron ([Al,B]MCM-22). The effect of platinum introduction was also investigated. The strong decrease in the Br酶nsted acidity, concomitant to the dealumination procedure, appears unfavorable since it leads to a drastic diminish of the degree of EB conversion, not compensated by satisfactory level of m-xylene isomerization. [Al,B]MCM-22 is a modification with much better performance, most probably because it contains both strong, Al-connected acid sites but in lower amount than in the parent sample, and weaker boron-generated sites and practically no any Lewis sites.

Parent zeolite [Al]MCM-22 as well as B-substitution possess promising properties for ethylbenzene-m-xylene mixture transformation catalyst with adequate degree of EB conversion and extent of p-xylene approach to equilibrium as well as low xylene loss.