溴酚蓝-碱土金属离子-十八醇热变色复配物的制备及热变色性

以溴酚蓝 (BPB)、碱土金属离子为原料 ,十八醇为溶剂制备了标题复配物 ,反应时间为 2h ,反应温度为 1 1 5℃ ,产率约为 87%。当m(BPB)∶m(CaCl2 )∶m(十八醇 ) =1∶1∶2 5时 ,加热至 55℃左右 ,复配物由亮绿色变为黄色 ,冷却 2～ 3min又由黄色变为亮绿色。经过 50 0次左右的热变色实验 ,该复配物仍具有较好的变色可逆性及稳定的变色温度。UV -Vis、DSC测定结果表明 :热变色性是由于在低温及加热时 ,溴酚蓝与碱土金属离子形成的配合物发生配位 -解离过程 ,使溴酚蓝产生内酯环式与醌式两种结构的互变 ,引起紫外 -可见吸收光谱的最大吸收峰发生位移 ,从而引起颜色的变化。

Preparation and Thermochromism of Thermochromic Composite Material BPB-Alkali Earth Metal Ions-Octadecyl Alcohol

The title compound was prepared in the solvent octadecanol with bromophenol blue(BPB) and alkali earth metal ions as raw materials.The reaction time was 2 h,the reaction temperature was 115 ℃,and yield of the product was about 87%.When the mass ratio of BPB∶CaCl 2∶octadecanol=1∶1∶25,the color of composite material changed from bright green to yellow on heating up to 55 ℃,and became bright green again on cooling for two or three minutes.The composite material still possessed good reversibility of color change and stability of thermochromism temperature after 500 thermochromic experiments.Based on the identification of UV-Vis spectra and DSC data,the thermochromic mechanism is due to coordination of the BPB alkali earth metal ions complex at lower temperature and dissociation at higher temperature.The coversion between lactone and quinoid structures of BPB causes the shift of UV-Vis absorption spectra and thus the change of color.