2001 Volume 34 Issue 12 Pages 1557-1561
We have carried out a detailed and systematic study to derive a quantitative understanding for the mechanism of the liquid-phase reaction of methylcyclopentane on ZSM-5 catalyst in a stirred batch reactor and at five temperatures between 110 and 175°C. The rate constants (k) and catalyst deactivation (kd) were obtained on the basis of the cyclohexane by a ring-expansion of methylcyclopentane with the selectivity of 92% or over. The rate of deactivation of ZSM-5 is as large as about 100 times of an activation rate. The activation parameters for the isomerization of methylcyclopentane are ΔH‡ = 11.87 kcal/mol and ΔS‡ = −55.9 cal/(mol K). As the conversion increases, the yields of 2-methylpentane and cyclohexane are linearly increased, but those of 3-methylpentane and C5- are sharply and nonlinearly increased. The scheme of methylcyclopentane reaction over ZSM-5 is as follows: MCP → CH (main reaction) or 2-MP → 3-MP or C5-. Higher reaction temperature favors cracking reaction (ring opening or cracked micromolecules) against the isomerization by a ring expansion.