부산대학교 도서관

In this work, thermal decomposition processes of (R)-(–)-phenylephrine hydrochloride (R-PEHC) in nitrogen (N2) and air atmosphere were investigated by multiple scanning rate method ranged from 300 to 950 K under 0.1 MPa. Five kinds of heating rates including 5 K min−1, 10 K min−1, 15 K min−1, 20 K min−1 and 25 K min−1 were applied during determination process of thermogravimetric differential scanning calorimetry (TG-DSC) of R-PEHC. Thermal decomposition processes were analyzed comprehensively according to TG-DSC results, bond length and bond energy data. Results indicated that thermal decomposition process of R-PEHC in N2 could be divided into three stages according to breaking of chemical bond, while thermal decomposition process in air was more complex. The similarity between two kinds of decomposition processes was that the first stage was the fractures of C···C and C···N on straight chain; meanwhile, first stage was considered as active decomposition stage. Given the importance of first stage of thermal decomposition process, corresponding average activation energies were calculated by Flynn–Wall–Ozawa and Starink method. Besides, based on obtained activation energy values, the pre-exponential factor and kinetic equation of thermal decomposition process were obtained by Málek method. Furthermore, based on results of kinetics parameters, theoretical storage period of R-PEHC in selected atmospheres (N2, air) and thermodynamic parameters of first stage of thermal decomposition process were also investigated. The results suggested that storage periods of R-PEHC in selected atmospheres were not less than three years at 298.15 K; meanwhile, thermal decomposition processes in selected atmospheres were always endothermic, non-spontaneous and entropy reduction process. [ABSTRACT FROM AUTHOR]