Future regulations for the limitation of sulfur and aromatics in fuels driven by the European Auto Oil Program (AOP II) stimulate the need for an alternative utilization of the resulting surplus of pyrolysis gasoline (pygas). The conversion of heavy pyrolysis gasoline into valuable steam cracker feedstock with a maximum yield Of C-2-C-4 n-alkanes is achieved via the ARINO((R)) two-step process, jointly developed by Linde, VEBA Oil and Sud-Chemie. The first step involves a hydrogenation of aromatics to naphthenes followed by the subsequent ring opening and cracking in the second step. Sud-Chemie developed a new commercial cracking catalyst for the second step of the ARINO((R)) process with the aim to maximize the yield Of C-2-C-4 n-alkanes at low formation of methane and aromatics. The ring opening and cracking reaction of naphthenes was studied in a bench scale tubular reactor over extruded H-ZSM-5 based zeolite catalysts. In a series of screening tests using a commercial, hydrogenated and desulphurized heavy pyrolysis gasoline, the influence of the preparation parameters such as zeolite acidity, palladium content as well as the type of binder were investigated. Furthermore, the influence of the process conditions space velocity and temperature was studied. High yields Of C-2-C-4 n-alkanes at low formation of undesired methane and aromatics were achieved over an alumina bound zeolite with medium Bronsted acidity loaded with palladium. The reduction of the space velocity resulted in an increase in the C-2-C-4 n-alkane yield and lower formation of aromatics, but a simultaneous increase in the methane make. Raising the temperature from 280 to 370 degreesC significantly increased the catalyst activity. (C) 2004 Elsevier B.V. All rights reserved.