Comparative characterization of thermal isomerization rates of 6‐phenyl‐1,5‐diazabicyclo[3.1.0]hexane at convection and microwave heating

• Published in: Journal of physical organic chemistry Vol. 31; no. 7
• Main Authors: Kornilova, Tatiana A., Kostikov, Rafael R., Khlebnikov, Alexander F., Zenkevich, Igor G.
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 01-07-2018
• Subjects: 1‐(benzyl)‐4,5‐dihydro‐1H‐pyrazole; 6‐phenyl‐1,5‐diazabicyclo[3.1.0]hexane; activation parameters; Chlorobenzene; convection and microwave heating; Convection heating; Heating rate; Isomerization; Microwave heating; Pyrazole; Rate constants; thermal isomerization; Thermodynamic properties; Toluene
• ISSN: 0894-3230; 1099-1395
• DOI: 10.1002/poc.3843

Rate constants of thermal isomerization of 6‐phenyl‐1,5‐diazabicyclo[3.1.0]hexane into 1‐(benzyl)‐4,5‐dihydro‐1H‐pyrazole at convection and microwave heating in toluene and chlorobenzene (solvents) were determined within the temperature range 90°C to 120°С. These data were used for the calculation of activation parameters of isomerization. It is shown that microwave heating increases the rate constants at the same temperature by a factor of 2 to 2.5 as compared with those using convection heating. The reason is that the effective temperature of microwave heating exceeds that of convection heating by 6°C to 9°С in toluene and by 12°C to 20°С in chlorobenzene as solvent.
Rate constants and activation parameters of thermal isomerization of 6‐phenyl‐1,5‐diazabicyclo[3.1.0]hexane into 1‐(benzyl)‐4,5‐dihydro‐1H‐pyrazole at convection (Δ) and microwave (MW) heating in toluene and chlorobenzene as the solvents were determined within the temperature range of 90°C to 120°C. It is shown that MW heating increases the rate constants at the same temperature by a factor of 2 to 2.5 as compared with those using Δ‐heating. The reason is that the effective MW temperatures exceed those of Δ‐heating by 6°C to 9°C in toluene and by 12°C to 20°C in chlorobenzene.