CHINESE JOURNAL OF CATALYSIS Volume 33, Issue 1, 2012 Online English edition of the Chinese language journal Cite this article as: Chin. J. Catal., 2012, 33: 70–84. Received 3 August 2011. Accepted 21 September 2011. *Corresponding author. Tel.: +49-711-685 64060; Fax: +49-711-685 64065; E-mail: jens.weitkamp@itc.uni-stuttgart.de Copyright © 2012, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier BV. All rights reserved. DOI: 10.1016/S1872-2067(10)60278-1 ARTICLE Catalytic Ring Opening of Perhydroindan - Hydrogenolytic and Cationic Reaction Paths Giuseppe BELLUSSI 1 , Andreas HAAS 2 , Sandra RABL 2 , Dominic SANTI 2 , Marco FERRARI 1 , Vincenzo CALEMMA 1 , Jens WEITKAMP 2, * 1 Eni S.p.A., R&M Division, Via F. Maritano 26, 20097 San Donato Milanese, Italy 2 Institute of Chemical Technology, University of Stuttgart, 70550 Stuttgart, Germany Abstract: Perhydroindan (bicyclo[4.3.0]nonane) was converted in a flow-type apparatus under a hydrogen pressure of 5 MPa on six dif- ferent catalysts, namely on a bifunctional Pd/Na,H-Beta zeolite, on Ir/Na,H-Y and Pt/Na,H-Y zeolites with a low concentration of Brønsted acid sites, and on three catalysts containing the three noble metals on the non-acidic support silica. On the bifunctional zeolite Pd/Na,H-Beta, skeletal isomerization of perhydroindan was the primary reaction followed by opening of one naphthenic ring, the formation of open-chain nonanes in low yields of ca. 6%, and hydrocracked products C 8 -. The carbon number distribution of the latter was vol- cano-shaped with no C 1 , C 2 , C 7 , and C 8 indicating a carbocationic hydrocracking of C 9 precursors with one naphthenic ring. On Ir/Na,H-Y and Pt/Na,H-Y (“high-performance ring-opening catalysts”), ring opening and hydrocracking to C 8 - occurred by hydrogenolysis on the respective metal. Opening of the five-membered ring was found to be much faster than opening of the six-membered ring, in agreement with literature reports. The maximal selectivities of open-chain nonanes (OCNs) attained on Ir/Na,H-Y and Pt/Na,H-Y were very high, viz. 49% and 54%, respectively, and significantly better than those of the open-chain decanes observed previously with decalin as model hydro- carbon. The OCNs formed on Pt/Na,H-Y were much less branched than those formed on Ir/Na,H-Y which was interpreted in terms of the different hydrogenolysis mechanisms on both metals. Valuable ancillary mechanistic information was obtained from the selectivities of perhydroindan hydroconversion on the three noble metals on silica. In contrast to Pd/silica, Ir/silica and Pt/silica gave appreciable selec- tivities of OCNs as well, yet the maximum values of these selectivities were lower than those obtained on the two high-performance zeolite catalysts. Key words: ring opening; hydrogenolysis; bifunctional catalysis; perhydroindan; open-chain nonanes; noble metals; silica; zeolites Contributing to the manufacture of high-quality, environ- mentally benign transportation fuel is among the important tasks of modern catalysis. Today's diesel fuels, for example, have to meet a variety of rather stringent specifications which pertain, inter alia, to the ignition characteristics in the engine, the cold-flow properties, the propensity of forming soot and particulate matter, and the amount and composition of the exhaust gas. Moreover, with the ongoing trend of using diesel engines in passenger cars, the consumption of high-quality diesel fuel has been steadily increasing in many regions of the world. In this context, upgrading of low-quality refinery streams in the boiling range of diesel, such as light cycle oils from fluid catalytic crackers or middle distillates from delayed or fluid cokers, into hydrogen-rich blending components for diesel fuels is of ever increasing attractiveness. Polynuclear aromatic hydrocarbons (PAHs) are particularly undesired constituents of diesel fuels. They have very low cetane numbers (CNs) [1,2] and poor cold-flow properties, and they are generally considered to be precursors of particulate matter. Moreover, due to their very low hydrogen content, they give rise to relatively high emissions of carbon dioxide. Probably the best solution of the PAH problem is their selective catalytic conversion into hydrogen-rich hydrocarbons under retention of the carbon number. An ideal upgrading of PAH-rich diesel fractions would entail a complete catalytic hydrogenation of the aromatic ring system to multi-ring naphthenes followed by their ring opening (or, synonymously, hydrodecyclization) into naphthenes with a lower number of