论文部分内容阅读
采用热重法(TG)和差示扫描量热法(DSC)测定加巴喷丁(GBP)在氮气氛和空气氛中的热分解过程,测定GBP、热分解过程中不同阶段残余物和气化物的红外光谱,探讨GBP的热分解机理。根据不同升温速率下的热重曲线计算GBP热分解反应的动力学参数,采用Dak in方程推算GBP在各种温度下的预期寿命。结果表明,GBP的热分解过程是二阶段过程,第一阶段是分子内环化成加巴喷丁内酰胺(GBP-L),第二阶段是GBP-L蒸发。在氮气氛中,GBP第一阶段热分解(内酰胺化)表观活化能Ea=136.0 kJ/mol,指前因子A=7.58×1014m in-1;第二阶段热分解(蒸发)表观活化能Ea=76.0 kJ/mol,指前因子A=7.76×107m in-1;在空气氛中,第一阶段表观活化能Ea=136.1 kJ/mol,指前因子A=7.76×1014m in-1;第二阶段表观活化能Ea=68.5 kJ/mol,指前因子A=8.13×106m in-1。GBP在常温下有较好的热稳定性。
The thermal decomposition process of gabapentin (GBP) in nitrogen atmosphere and air atmosphere was determined by TG and DSC, and the infrared spectra of GBP and residue and gasification products in different stages of thermal decomposition were determined. , To explore the thermal decomposition mechanism of GBP. The kinetic parameters of GBP thermal decomposition reaction were calculated according to TG curves at different heating rates. The Dak in equation was used to estimate the expected life expectancy of GBP at various temperatures. The results show that the thermal decomposition process of GBP is a two-stage process. The first stage is the intramolecular cyclization into gabapentolactam (GBP-L) and the second stage is the GBP-L evaporation. Under nitrogen atmosphere, the apparent activation energy of thermal decomposition (lactamization) of GBP in the first stage of GBP was 136.0 kJ / mol and the pre-exponential factor was 7.58 × 1014 m in-1. The second stage of thermal decomposition (evaporation) In the air atmosphere, the apparent activation energy Ea = 136.1 kJ / mol and the pre-exponential factor A = 7.76 × 1014 m in-1 The apparent activation energy Ea of the second stage was 68.5 kJ / mol and the pre-exponential factor A was 8.13 × 106 m in-1. GBP at room temperature has better thermal stability.