Isomerization of cyclohexane, n-hexane and their mixtures on zeolite catalyst

摘要

The skeletal rearrangement of cyclohexane, n-hexane and their mixtures has beeninvestigated on platinum/hydrogen-mordenite at 180-270℃, 5-40 bar total pressure andhydrogen to hydrocarbon molar ratio 1-20. The apparent activation energy for cyclohexaneisomerization is 114 kJ/mol, for n-hexane isomerization 123 kJ/mol. The reaction order up to4 bar in cyclohexane is 0.18, in n-hexane 0.39. The reaction orders in hydrogen up to 36 barare –0.57 and –0.65 in the case of cyclohexane and n-hexane, respectively. Rate equationswere derived and parameters involved determined for the isomerization of pure paraffins andtheir binary mixtures. The rate of single paraffins can be described with sufficient accuracypresuming rate determining skeletal rearrangement of the carbenium ion, while in binarymixtures rate determining transport in the micropores is to be assumed. At high conversionsof cyclohexane hydroisomerization products of higher molecular weight than the feed areformed through alkylation and disproportination reactions.