Kinetics and mechanism of pyrolysis of sulphonyl hydrazones and oximes. Part 2 - Structural effects and molecular reactivity

The kinetics and products of the pyrolytic reaction of six tosyl arenecarbo xaldoximes were studied over the temperature range ca 334 - 401 K to yield the following Arrhenius log A/s(-l) and E-a/kJ mol(-1), respectively: 10.92 and 98.25 for tosyl benzaldoxime and 10.83 and 100.4 for m-nitro-, 10.66 a nd 97.53 for p-chloro-, 11.80 and 107.8 for m-chloro-, 11.60 and 101.5 for p-methyl- and 10.84 and 97.75 for p-methoxybenzaldehyde O-[(4-methylphenyl) sulphonyl]oxime. At 500 K, the oxime compounds were found to be 9.4 x 10(3 ) - 2.7 x 10(4)-fold more reactive than their hydrazone analogues. Copyrigh t (C) 1999 John Wiley & Sons, Ltd.