Catalytic reactions of five- and six-membered cycloalkanes under a pressure of hydrogen at high temperature

Summary

• 1. It has been found that cyclopentane, under a high pressure of hydrogen (20 atm), in presence of a platinum-alumina catalyst, and at 460°, undergoes far-reaching changes with formation not only of hydrogenolysis products (pentane, and isopentane formed by its isomerization), but also hydrogenosynthesis (methyl-cyclopentane, hexane and its isomers, benzene, toluene, xylene, polymethylbenzenes).

• 2. Under similar conditions (hydrogen pressure, 15 atm), methylcyclopentane is converted into a mixture of cyclopentane, pentane, 2-methylbutane, hexane and its isomers, benzene, toluene, xylene, and polymethylbenzenes.

• 3. In contact with the same catalyst at 460° under a pressure of hydrogen (15 atm), cyclohexane gives a mixture of benzene, methylcyclopentane, cyclopentane, hexanes, pentanes, toluene, xylenes, and polymethylbenzenes.

• 4. The synthesis reactions are in all cases to be explained by the alkylation of hydrocarbon molecules (cyclopentane, benzene, toluene) by means of methylene radicals arising under the given conditions as a result of the methane breakdown of cycloalkanes at the surface of the specific platinum-alumina catalyst.