IR study on the reaction path of skeletal isomerization of 1-butene

The reaction molecularity of the skeletal isomerization on zeolite was dedu ced from IR spectra of adsorbed butene recorded with heating. Formation of polymeric species from adsorbed butene was observed on ZSM-5 and beta zeoli tes, non-selective catalysts for isobutene production. On the other hand, m ost of butene molecules adsorbed on ferrierite and clinoptilolite behaved m onomolecularly, resulting in complete desorption even at ambient temperatur e. The exceptional selectivity for isobutene of ferrierite and clinoptiloli te was ascribed to the sparse distribution of adsorbed butene molecules, su ppressing bimolecular oligomerization and enhancing monomolecular skeletal isomerization.