Authors:San-Ping Chen, Na Li, Qing Wei, and Sheng-Li Gao
A novel complex [Ni(H2O)4(TO)2](NO3)2·2H2O (TO = 1,2,4-triazole-5-one) was synthesized and structurally characterized by X-ray crystal diffraction analysis. The decomposition
reaction kinetic of the complex was studied using TG-DTG. A multiple heating rate method was utilized to determine the apparent
activation energy (Ea) and pre-exponential constant (A) of the former two decomposition stages, and the values are 109.2 kJ mol−1, 1013.80 s−1; 108.0 kJ mol−1, 1023.23 s−1, respectively. The critical temperature of thermal explosion, the entropy of activation (ΔS≠), enthalpy of activation (ΔH≠) and the free energy of activation (ΔG≠) of the initial two decomposition stages of the complex were also calculated. The standard enthalpy of formation of the new
complex was determined as being −1464.55 ± 1.70 kJ mol−1 by a rotating-bomb calorimeter.
Authors:Bing Xue, Kai Jia, Jie Xu, Na Liu, Ping Liu, Chongfu Xu, and Yongxin Li
An efficient and novel method to prepare KNO3/NaY solid base catalysts was developed. High selectivity for phenetole along with high conversion of phenol was obtained in the vapor phase O-alkylation of phenol with diethyl carbonate over KNO3 modified NaY zeolite. Experimental results showed that a large number of basic sites on KNO3/NaY were generated mainly during catalytic evaluation, which was responsible for the outstanding catalytic performance. Furthermore, the excess KNO3 loadings might lead to the blockage of the pores in the NaY zeolite and decrease the catalytic activity.
Authors:Na Zhou, Tao Li, Lianfeng Ai, Chunhai Guo, Juan Zhang, Shan Fu, and Qiao Wang
Lacosamide, a new type of antiepileptic drug, was subjected to forced degradation under the conditions of hydrolysis (acidic and alkaline), oxidation, dry heat, and photolysis to characterize its possible degradation products. The drug showed significant degradation under acidic, alkaline and oxidative conditions. The degradation products were separated on an Agilent Zorbax SB-C18 column with gradient elution using a mobile phase consisting of acetonitrile and ammonium acetate (0.002 mol/L) with formic acid as additive. A combination of liquid chromatography hybrid triple quadrupole-linear ion trap mass spectrometry (LC–QqLIT-MS) and liquid chromatography hybrid ion trap/time-of-flight mass spectrometry (LC-IT/TOF-MS) was used to identify degradation products. A total of 7 products including 4 novel degradation products were characterized. The mechanisms of degradation products of lacosamide were discussed. Application of the method to study degradation products of lacosamide provided fragment information, allowing further investigation of the degradation pathways and intrinsic stability of the drug.