Dependence of the directions of C6-dehydrocyclization of n-octane on the distribution of electron density in the molecule

Abstract

1. The hydrogen pressure changes the selectivity of a 0.3% Pt-Al2O3 catalyst in the C6-dehydrocyclization of n-oetane: at 450°, when the hydrogen pressure was increased from 4.5 to 19.5 atm, the ratio of o-xylene to ethylbenzene formed increased on the average from 1.27 to 1.40. 2. By comparing the results obtained with the literature data, it was shown that the reactions of C6-dehydrocyclization of n-octane and hydrogenolysis of methylcyclopentane are covered by a single law: with increasing hydrogen pressure, the fraction of n-octane and methylcyclopentane molecules entering into the above-mentioned reactions with the carbon atoms with the least negative charges increases. 3. It is hypothesized that the direction of the reactions of C6-dehydrocyclization of n-octane and hydrogenolysis of methylcyclopentane is determined by the orientation of the molecules during adsorption and by the formation of a monoadsorbed complex by one carbon atom or another.