Transformations of hexane, methylcyclopentane, and cyclohexane in presence of a rhenium-alumina catalyst and of hydrogen under pressure

Summary

• 1. A study was made of the catalytic properties of five rhenium-alumina catalysts of different rhenium contents (5, 15, and 20%) and with additions of ZnO and HF; they were used in the treatment of cyclohexane, hexane, and methylcyclopentane at 290–480° in presence of hydrogen at 5–30 atm at a space velocity of 1.0 hr⁻¹ and a hydrogen to hydrocarbon ratio of 5.

• 2. Under the conditions investigated aromatic hydrocarbons (up to 78%) were formed only from cyclohexane. At temperatures above 400° and hydrogen pressures of 20 and 30 atm much hydrocracking of hydrocarbons was observed (about 60%). Hexane gave a particularly large amount of hydrocracking (up to 90%).

• 3. The most active catalyst found for the dehydrogenation of cyclohexane (380°,5 atm), the hydrogenolysis of hexane (300°, 5 atm), and the hydrogenolysis of methylcyclopentane (305°, 5 atm) was 20% Re-Al₂O₃.

• 4. The catalyzates of cyclohexane, hexane, and methylcyclopentane were subjected to detailed investigation by gas-liquid chromatography.