The thermal reaction of 2‐pentene around 500°C at low extent of reaction

Abstract The thermal reaction of 2‐pentene (cis or trans) has been performed in a static system over the temperature range of 470°–535°C at low extent of reaction and for initial pressures of 20–100 torr. The main products of decomposition are methane and 1,3‐butadiene. Other minor primary products have been monitored: trans‐2‐pentene, trans‐ and cis‐2‐butenes, ethane, 1,3‐pentadienes, 3‐methyl‐1‐butene, propylene, 1‐butene, hydrogen, ethylene, and 1‐pentene. The initial orders of formation, 0.8–1.1 for most of the products and 1.5–1.8 for 1‐pentene, increase with temperature. The formation of the products and the influence of temperature on their orders can be essentially explained by a free radical chain mechanism. But cis–trans or trans–cis isomerization and hydrogen elimination from cis‐2‐pentene certainly involve both molecular and free radical processes. The formation of 1‐pentene mainly occurs from the abstraction of the hydrogen atom of 2‐pentene by resonance stabilized free radicals (C5H9.).