Investigation of the influence of thiophene on the properties of an aluminoplatinate catalyst under the conditions of the dehydroisomerization of m ethylcyclopentane

Abstract

1. The conversions of methylcyclopentane with additions of various amounts of thiophene-S35, as well as pure methylcyclopentane in the presence of a 1% Pt-Al2O3 catalyst, were investigated at 500°, 20 atm, volume velocity 2 h−1, and molar ratio H2:HC=5 ∶1. 2. When the thiophene concentration in the initial methylcyclopentane is varied from 0.5 to 6%, the dehydroisomerizing ability of the catalyst decreases from 32.1 to 3.4% after ten hours of work; the strongest effect of thiophene is observed within the concentration range 0.5–1.18%. The yield of benzene from methylcyclopentane containing thiophene decreases continuously during the entire experiment. The rate of regeneration of the deactivated catalyst by the pure hydrocarbon is higher, the lower the concentration of the poison in the initial mixture during poisoning. 3. As the thiophene concentration in methylcyclopentane is increased from 0.5 to 6%, the amount of sulfur deposited on the catalyst is increased from 0.022 to 0.149% by weight. Moreover, the activity of the catalyst varies linearly as a function of its sulfur content in the catalyst comprises 30–35% of the original amount deposited.