Hydroisomerization cyclohexane

Pt-promoted Cs2.5 catalyst also is efficient for the skeletal isomerization of n-butane, n-pentane, n-hexane, and n-heptane. Pt-Cs2.5 supported on silica is effective for isomerization of cyclohexane and the hydroisomerization of benzene to methylcyclopentane. ... 

A palladium-hydrogen-mordenite catalyst with a 10.8/1 silica/alumina mole ratio was evaluated for the hydroisomerization of cyclohexane. The rate of reaction followed a first-order, reversible reaction between cyclohexane and methylcyclopentane. The energy of activation for this reaction between 400° and 500°F was 35.5 it 2.4 kcal/mole. Cyclohexane isomerization rates decreased with increasing hydrogen and cyclohexane-plus-methylcyclopentane partial pressure. These effects are compatible with a dual-site adsorption model. The change of the model constants with temperature was qualitatively in agreement with the expected physical behavior for the constants. 

The reaction of cyclohexene over differently dealuminated H-Y samples at 370 K (isomerization to methylcyclopentene and hydroisomerization to methyl-cyclopentane, hydrogen transfer resulting in benzene and cyclohexane, cracking and coke formation) was monitored by Joly et al. [904] via in-situ IR spectroscopy in an IR flow-reactor cell coupled with a gas chromatograph. A good correlation was reported between the activity of the Bronsted acid sites and their strength... 

An extensive study of the reactions of pure hydrocarbons, including alkanes, cycloalkanes, alkenes and aromatics has been made in the presence of hydrogen, these catalysts are active for (1) isomerization of alkanes, cycloalkanes, and alkyl-aromatics, (2) hydroisomerization of alkylcyclo-pentanes to aromatics, and (4) dehydrogenation of alkanes and cyclohexanes to aromatics. The activity and selectivity of these catalysts are dependent primarily on (1) the hydrogenation-dehydrogenation component used and its concentration, (2) the acidity of the oxide support, and (3) the reaction conditions. The effect of these factors on the conversion of pure hydrocarbons as well as the mechanism of these reactions will be discussed. 

The five member ring cyclopentanes must be hydroisomerized to give a cyclohexane intermediate prior to dehydrogenation to the aromatic. 

After cyclization, the cyclohexane should rapidly undergo dehydrogenation to the analogous aromatic. Cyclopentanes will undergo hydroisomerization to cyclohexane, followed by dehydrogenation to the aromatic. 

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