[Bmim]BF_4及[Bmim]CF_3SO_3中不同形貌LLM-105晶体的制备及表征

Preparation and Characterization of LLM-105 Crystals with Different Morphology in the Ionic Liquid

以[Bmim]BF4及[Bmim]CF3SO3两种离子液体为溶剂,在不同溶液温度、水的体积和静置条件下,重结晶得到了三种不同形貌的2,6-二氨基-3,5-二硝基吡嗪-1-氧化物(LLM-105)晶体,采用扫描电镜,X射线粉末衍射,差示扫描量热-热失重,红外检测及纯度分析对重结晶后晶体的形貌、结构、热性能及纯度进行了表征。结果表明:重结晶得到的矩形实心棒状、有孔、片状三种LLM-105晶体的主要衍射峰位置与原料完全一致,只在2θ为11°、21°和45°附近位置的衍射峰出现明显增强,其他位置的衍射峰强度减弱,晶体具有不同的显露晶面,其晶习发生了改变,且纯度均在94%以上,结构相对完整的矩形实心棒状晶体的最大放热峰及起始分解温度分别为353℃和323.6℃,相对于原料分别提高了约10℃和40℃,热稳定性最好。

The 2,6-diamino-3,5-di-nitropyrazine-1-oxide（LLM-105） crystals with three different morphology were recrystallized using two ionic liquids of[Bmim]BF4 and[Bmim]CF3SO3 as solvents under different solvent temperature,water volume and standing conditions.The morphology,crystal structure,thermal property and purity of the crystals were characterized by scanning electron microscope,X-Ray powder diffraction,differential scanning calorimetry-thermogravimetry,fourier transform infrared spectroscopy and purity analysis.Results show that the recrystallized rectangular micro-rod,hole shape and plate-like LLM-105 crystals have the same diffraction peak positions as the raw materials,only the intensity have obviously enhanced at 11°,21°,45° and weakened at other positions.Compared with the raw materials,the crystals habits have changed and present different facets,while the purity have slightly improved（above 94%）.The relative regular structured rectangular micro-rod crystal exhibits the best thermal stability with the exothermic peak temperature of 353 ℃ and initial decomposition temperature of 323.6 ℃ which have improved by 10 ℃ and 40 ℃ than that of the raw materials,respectively.