The Newman-Kwart rearrangement: a microwave kinetic study.
The kinetic profile of the Newman-Kwart rearrangement has been evaluated using microwave heating. After first demonstrating equivalence between conventional convective heating and microwave heating, data was gathered and analyzed to determine the effects of substituent, solvent, and concentration on the reaction order. Reaction rate constants, Arrhenius constants, and activation energies have been determined. The reaction rate shows strong sensitivity to the substituent and modest sensitivity to the solvent. At high concentrations, the reaction order increases from the previously reported first-order to a mixed first/second-order reaction. Overall, this re-evaluation of the Newman-Kwart rearrangement has shown the reaction rate order to be more complex than previously thought. In addition, microwave heating has proven ideal for the rapid collection of data to facilitate this type of kinetic study.
Gilday
John P
JP
AstraZeneca, Process Research and Development, Avlon Works, Severn Road, Hallen, Bristol, BS10 7ZE, UK.
Lenden
Philip
P
Moseley
Jonathan D
JD
Cox
Brian G
BG
D007700:Kinetics; D008872:Microwaves; D008956:Models, Chemical; D015394:Molecular Structure; D012997:Solvents; D013696:Temperature
D012997:Solvents