In situ FT-IR study on the reaction path of skeletal isomerization of n-butene over different zeolites

Adsorption and reaction of 1-butene, cis- and trans-2-butene and isobutene on H-ZSM-5 and H-FER were studied by FF-IR spectroscopy between 30-450 degr eesC. n-Butenes were monomolecularly adsorbed via pi -bonding on H-FER at 3 0 degreesC. At elevated temperatures butadiene was monitored on H-FER, whic h was then transformed into dialkyldiphenyl. On H-ZSM-5 all butene isomers were adsorbed via pi -bonds, followed by dimerization. From these results a nd from catalytic measurements a monomolecular pathway is proposed on H-FER and a bimolecular one on H-ZSM-5. (C) 2001 Elsevier Science B.V. All right s reserved.