Reactions of alkylcyclopentanes over pt catalysts

Abstract Cyclopentane, methyl-, ethyl-, 1,1-, 1,2- and 1,3-dimethylcyclopentanes were reacted over Pt black and Pt/SiO 2 (EUROPT-1) in a static-circulation reactor at 603 K. Ring opening products, olefins, aromatics and hydrogenolysis products were observed. The yields and selectivities were determined as a function of the hydrogen pressure. Overall yields increased monotonically with increasing hydrogen pressure; at the same time, ringopening products became predominating instead of olefins, which were the main products at lower hydrogen pressures. Ring opening was close to random fission on Pt/SiO 2 , and was hindered in the vicinity of the alkyl substituent over Pt black. The reactivity of the molecules decreased with increasing molecular mass. Aromatic production was not significant. 1,1-Dimethylcyclopentane was an exception in several respects: it was more reactive than other C 7 , feed molecules, its ring opening was always selective and the relative amount of aromatic products the highest of all reactants. The possible reaction pathway(s), the likely surface intermediates and the effect of molecular structure are discussed.