Kinetic and mechanisms aspects of nitrogen elimination from 4-methyl-1-pyrazoline and its deuterated derivatives have been investigated in the gas phase with the B3LYP, MPW1PW91 and PBEPBE methods, using the 6-311+G(d,p) basis sets. This reaction may proceeds through the three paths which include one step-size radical and two concerted mechanisms. Theoretical calculations show that the radical mechanism is suitable from the activation energy point of view. Although calculated kinetic parameters and kinetic isotope effects for the first mechanism are accordance to experimental results but the second mechanism from the kinetic isotope effects point of view can be used for propene formation as a product which competes with the major product of cyclopropane.

Keywords