Gas-phase eliminations. Part X. Kinetics of the thermal decomposition of 3-chlorobutan-2-one, 3-chloropentan-2-one, and 4-chloropentan-2-one

Abstract

The thermal decompositions in ‘seasoned’ reaction vessels of 3-chlorobutan-2-one and 3-chloropentan-2-one in the range 390–440° and of 4-chloropentane-2-one in the range 335–390° are homogeneous, first order, and unimolecular with rate constants k₁= 5·49 × 10¹¹ exp (–49,050/RT) sec.^–1, 6·31 × 10¹² exp (–50,800/RT) sec.^–1, and 1·66 × 10¹²exp (–44,500) sec.^–1 respectively. The effect of the acetyl group in the α-position reduces the rate of elimination while in the β-position it slightly increases it.