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857489 
Journal Article 
NiPt/HY Zeolite Catalysts for Disproportionation of Toluene and 1,2,4-trimethylbenzene 
Bhavani, A; Karthekayen, D; Rao, A; Lingappan, N 
2005 
Yes 
Catalysis Letters
ISSN: 1011-372X
EISSN: 1572-879X 
103 
1-2 
89 
WOS:000231352000013 
NiPt/HY zeolite catalysts with different Ni contents were prepared and applied to the disproportionation of toluene and 1,2,4-trimethylbenzene in the temperature range 250400 C. The line broadening XRD analysis indicates that the increasing Ni addition decreases the crystallinity of zeolites. ESCA studies show the complete reduction of Ni species up to 0.3 wt.% Ni addition over 0.1 wt.% Pt/H-Y and further addition leads to the occurrence of unreduced nickel species as NiAl2O4. A TEM study shows the formation of bimetallic (NiPt) particles of nanoscale size and the average particle size is found to increase with increasing Ni loading. Acidity measurements by NH3-TPD and pyridine-adsorbed FTIR spectroscopy show the increasing occupation of acid sites by increasing nickel loading. The catalytic activity of NiPt/HY zeolite and Pt/HY catalysts was compared and it was found that addition of Ni up to 0.3 wt.% increases conversion of toluene and 1,2,4-trimethylbenzene, disproportionation selectivity and sustainability of the catalysts. Further addition of Ni leads to a decrease in conversion and disproportionation selectivity and increasing dealkylated products, which may be due to the presence of unreduced Ni species and pore blockage by large-sized bimetallic particles formed. [ABSTRACT FROM AUTHOR] Copyright of Catalysis Letters is the property of Springer Science & Business Media B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) 
catalysts; zeolites; toluene; TRANSMISSION electron microscopy; nickel; SPECTRUM analysis; 1; 1,2,4-trimethylbenzene; 2; 4-trimethylbenzene; disproportionation; platinum; zeolite-Y