A study of intermolecular hydrogen transfer from naphthenes to 1-hexene over zeolite catalysts

• Mechanism of hydrogen transfer was explained by deuterated naphthenes transformations.
• During the hydrogen transfer only one hydrogen atom is transferred from donor.
• Bronsted acid site of catalyst is a source of second hydrogen atom.

The mechanism of hydrogen transfers from naphthenes (methylcyclohexane, cyclohexane) or their deuterated derivatives to 1-hexene was specified over model acid zeolite catalysts (HREY or HZSM5). The composition of products is determined by two reactions-cracking and intermolecular hydrogen transfer. The monomolecular cracking reaction proceeds mostly on HZSM-5 zeolite, whereas the bimolecular hydrogen transfer reactions are catalyzed by the wide-pore HREY zeolite. It was found that during the hydrogen transfer from the naphthene molecule (hydrogen donor) to the olefin molecule (hydrogen acceptor) only one hydrogen atom is transferred, whereas the second hydrogen atom comes from the Brønsted acid site of the catalyst.

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