Experimental and theoretical study of the isomerisation of N-methylpyrrole

✍ Scribed by Alan Doughty; John C. Mackie; George B. Bacskay

• Book ID: 103034401
• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 695 KB
• Volume: 221
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)00267-3

✦ Synopsis

The isomerisation of N-methylpyrrole to 2-metbylpyrrole has been investigated experimentally by means of a single pulse shock tube over the temperature range 1000 to 1350 K and theoretically by ab initio calculations. Between 1000 and 1100 K the isomerization is found to occur via an intramolecular methyl shift. The experimental rate constant for this rearrangement was found to be k,,= 10'2s(*o~4) exp[ -56.2( f2.0) kcal mol-'/RT] s-r. Ab initio calculations gave Arrhenius parameters for the methyl shift in good agreement with the experimental values. Methyl shifting produces the intermediate 2-methyl-ZH-pyrrole which undergoes a hydrogen shift of low activation energy to form the product of isomerisation, 2-methylpyrrole. Above about 1240 K there is a competing free-radical process which produces methane, pyrrole and traces of higher molecular weight products.