Abstract:

Sulfadiazine N-methylpyrrolidone solvate (SD-NMP) was prepared by solution crystallization method. The molar ratio of sulfadiazine (SD) to N-methylpyrrolidone (NMP) in the solvate was 1:2 from the calculation of thermal gravimetric data. The desolvation bebavior of SD-NMP solvate was investigated by thermal gravimetric analysis, hot stage microscopy, scanning electron microscopy, powder X-ray diffraction and Fourier transform infrared spectroscopy. According to the same crystal habit and crystal form between the desolvation product of SD-NMP solvate and sulfadiazine crystal, it can be known that the formation and desolvation of SD-NMP solvate was a reversible transformation process. The desolvation kinetics of SD-NMP solvate under temperature of 70℃, 75℃, 80℃ and 85℃ was studied by use of the model fitting method according to the different reaction models. The results showed that the most appropriate model was the geometrical contraction one, and the desolvation of SD-NMP solvate was attributed to phase boundary reaction and the rate-limiting step was the inward advance of the phase boundary from the surface to the center of the crystals. The above research results were consistent with the WET3 theory.

Key words: sulfadiazine, N-methylpyrrolidone solvate, crystallization, chemical processes, kinetic modeling, desolvation kinetics mechanism

摘要：

通过溶液结晶方法制备了磺胺嘧啶N-甲基吡咯烷酮溶剂化合物(SD-NMP),根据热重数据计算可知其中磺胺嘧啶(SD)和N-甲基吡咯烷酮(NMP)的摩尔比是1:2。采用热重分析、热台显微镜、扫描电子显微镜、粉末X射线衍射和傅里叶红外光谱对SD-NMP溶剂化合物脱溶剂过程进行了表征,发现SD-NMP溶剂化合物晶体脱除溶剂后产物与磺胺嘧啶晶体的晶习、晶型相同,磺胺嘧啶溶剂化合物的形成和溶剂的脱除是一个可互相转变的过程。基于不同的反应模型,对70、75、80、85℃下SD-NMP溶剂化合物的脱溶剂过程动力学数据进行拟合,计算得到活化能,结果表明几何收缩模型能很好地描述SD-NMP溶剂化合物的脱溶剂过程,对应的机理为相界面反应,其控制步骤为相界面的推进,与WET3理论一致。

关键词: 磺胺嘧啶, N-甲基吡咯烷酮溶剂化合物, 结晶, 化学过程, 动力学模型, 脱溶剂动力学机理