Platinum-alumina cyclopentane aromatization

With platinum and palladium supported on acidic alumina, cyclopentanes are important intermediates of aromatization (44, 123-124). For example, n-heptane gave about 2-3 times more aromatic product than 2,4-dimethyl-pentane, whereas the formation of C5 cyclic products was about the same from both alkanes. Alkylcyclopentanes aromatized at a reasonable rate (123a). 

After a preliminary study of the properties of a number of platinum and nickel catalysts deposited on various carriers (activated carbon, chromia, alumina, molybdena, etc.) a platinum-alumina catalyst was selected for the present investigation with a 0.5 % Pt content. Cyclopentane (238.2 g) was passed over the catalyst at 0.43 hr. i space velocity, 20 atmospheres hydrogen pressure, and a temperature of 460 . As a result 184.3 grams of liquid product were obtained containing 9 % by volume of aromatics including benzene (81.9%), toluene, and p-xylene, and also w-pentane,... 

The considerable amoimts of aromatic hydrocarbons and methylcyclopentane that were found in the products are especially noteworthy. This new fact shows that under the conditions selected cyclopentane imdergoes a number of interesting reactions, an important part in which is played by methylene radicals arising from disintegration of the pentamethylene ring under the influence of the platinum-alumina catalyst ... 

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