Abstract Tenoxicam (TNX) is a non-steroidal anti-inflammatory drug. Its thermal decomposition processes were studied with thermogravimetry and differential thermal analysis. The produced gaseous products and residues during decomposition were detected and characterized using Fourier transform infrared spectroscopy. Combining with the molecular bond order distribution obtained from the quantum chemistry calculation, the thermal decomposition mechanism of TNX has been speculated. The kinetic parameters for thermal decomposition, such as activation energy Eα and the pre-exponential factor A, were obtained using the ATSM E1641 method. The prospective lifetime of TNX was estimated using the ATSM E1877 method. The results indicated that the thermal decomposition of TNX is a three-stage process. During the first stage of thermal decomposition, the main part of the molecule, including sulfamide, thiophene and amide, decompose simultaneously, and to form gasifiable small molecules and carbonized residues. The initial decomposition temperature in either nitrogen or air is about 204°C. For decomposition in nitrogen, the Eα and A for the initial thermal decomposition are 174.8 kJ mol−1 and 2.512 × 1017 min−1, respectively. For decomposition in air, the corresponding Eα and A are 179.4 kJ mol−1 and 7.943 × 1017 min−1, respectively. The TNX has good thermal stability under routine temperature.

中文翻译：

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替诺昔康的热分解机理和动力学

摘要 替诺昔康（TNX）是一种非甾体抗炎药。用热重法和差热分析法研究了其热分解过程。使用傅里叶变换红外光谱检测和表征分解过程中产生的气态产物和残留物。结合量子化学计算得到的分子键序分布，推测了TNX的热分解机理。使用 ATSM E1641 方法获得热分解的动力学参数，例如活化能 Eα 和指前因子 A。TNX 的预期寿命是使用 ATSM E1877 方法估计的。结果表明，TNX 的热分解是一个三阶段过程。在热分解的第一阶段，分子的主要部分，包括磺酰胺、噻吩和酰胺，同时分解，形成可气化的小分子和碳化残留物。在氮气或空气中的初始分解温度约为 204°C。对于在氮气中的分解，初始热分解的 Eα 和 A 分别为 174.8 kJ mol-1 和 2.512 × 1017 min-1。对于在空气中分解，相应的 Eα 和 A 分别为 179.4 kJ mol-1 和 7.943 × 1017 min-1。TNX在常规温度下具有良好的热稳定性。初始热分解的 Eα 和 A 分别为 174.8 kJ mol-1 和 2.512 × 1017 min-1。对于在空气中分解，相应的 Eα 和 A 分别为 179.4 kJ mol-1 和 7.943 × 1017 min-1。TNX在常规温度下具有良好的热稳定性。初始热分解的 Eα 和 A 分别为 174.8 kJ mol-1 和 2.512 × 1017 min-1。对于在空气中分解，相应的 Eα 和 A 分别为 179.4 kJ mol-1 和 7.943 × 1017 min-1。TNX在常规温度下具有良好的热稳定性。