Thermal reactions of mesityl oxide

Abstract

Mesityl oxide (4-methylpent-3-en-2-one) thermally decomposes in the range 412-490° give methylbutenes, carbon monoxide, isobutene, and methane as major products. The initial 20% of reaction follows first- order kinetics and is described by the equation k₁ = 10^14.22exp(-63240/RT) s^-1. A Rice-Herzfeld chain is proposed. Addition of hydrogen bromide leads to two reactions, one producing isobutene, carbon monoxide, and methyl bromide, and the other leading to polymerization. Likely steps in the polymerization are proposed.