THERMOLYSIS REACTION OF 2-ACETYL-1-OXO-5-MEMBERED, 2-ACETYL-1-OXO-6-MEMBERED, AND 2-ACETYL-1-OXO-7-MEMBERED RING

The rates of gas-phase thermolysis reactions of 2-acetylcyclopentanone 1,2-acetylcyclohexanone 2, N-acetylcaprolactam 3,2-acetylbutyrolacton e 4,2-acetyl-2-methylbutyrolactone 5, and 3-acetyl-2-oxazolidinone 6 h ave been measured over a temperature range of 50 K. They undergo unimo lecular first-order elimination reactions for which log A = 11.7, 11.7 , 11.2, 11.4, 11.5, and 11.1 s(-1) and E(a) = 193.4, 189.5, 153.2, 201 .0, 206.8, and 176.1 kJ mol(-1), respectively. The effect of the ring size together with the effect of a heteroatom in the ring on the rate of thermolysis reactions for compound 1-6 is the subject of this work. (C) 1995 John Wiley and Sons, Inc.