1-烷基-3-甲基咪唑多钨酸盐的合成及液晶行为

Synthesis and liquid crystal behavior of 1-alkyl-3-methylimdazolium polytungstates

以钨酸钠、溴化1-十六烷基-3-甲基咪唑(C16MimBr)和溴化1-十八烷基-3-甲基咪唑(C18MimBr)为主要原料合成了2个离子液体型多钨酸盐[C16Mim]2[W6O19]和[C18Mim]2[W6O19],并利用傅里叶变换红外(FTIR)、热重(TGA)、差式扫描量热仪(DSC)、偏光显微镜(POM)和变温X射线衍射仪(XRD)对[C16Mim]2[W6O19]和[C18Mim]2[W6O19]的性质进行了表征.结果显示[C16Mim]2[W6O19]和[C18Mim]2[W6O19]具有良好的热稳定性,均能够在330℃之前稳定存在,[C16Mim]2[W6O19]和[C18Mim]2[W6O19]的熔点/清亮点分别为74.6℃/97.5℃和83.7℃/116.4℃.DSC和POM测试证实[C16Mim]2[W6O19]和[C18Mim]2[W6O19]具有液晶性质,并通过变温XRD测试进一步确认[C16Mim]2[W6O19]和[C18Mim]2[W6O19]均为层状结构.

Two ionic liquid type polytungstates[C16Mim]2[W6O19]and[C18Mim]2[W6O19]were synthesized by using sodium tungstate,1-hexadecyl-3-methylimidazolium bromide and 1-octadecyl-3-methylimidazolium bromide as the main raw materials.The properties of[C16Mim]2[W6O19]and[C18Mim]2[W6O19]were characterized by infrared(FTIR),thermogravimetric(TGA),differential scanning calorimeter(DSC),polarizing microscope(POM)and temperature-dependent X ray diffraction(XRD).The results showed that[C16Mim]2[W6O19]and[C18Mim]2[W6O19]have good thermal stability and can exist stably before 330℃.The melting point/brightening point of[C16Mim]2[W6O19]and[C18Mim]2[W6O19]are 74.6℃/97.5℃and 83.7℃/116.4℃respectively.DSC and POM measurements confirmed that[C16Mim]2[W6O19]and[C18Mim]2[W6O19]have liquid crystal properties.The layered structures of[C16Mim]2[W6O19]and[C18Mim]2[W6O19]were further confirmed by analyzing temperature-dependent XRD measurements results.