文摘
Room temperature ionic liquids (RTILs) have intriguing high-pressure phase behavior, and investigation of how pressure affects phase transitions of RTILs might yield interesting results. We here present kinetically driven phase transitions of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([Emim][CF3SO3]) at different rates of 鈭?.3 and 鈭?.2 GPa/h up to 鈭? GPa. Two crystalline phases formed at 鈭?.3 and 鈭?.7 GPa with increasing pressure at lower compression rate of 鈭?.3 GPa/h; however, the amorphous phase solidified with superpressurized glass above 鈭?.3 GPa at higher compression rate of 鈭?.2 GPa/h. Notably, crystal polymorphism is discussed in view of the conformational isomerism of [Emim]+ cation and an unknown cation conformer is observed. These facts indicate that kinetic effect on pressure-induced phase transitions of [Emim][CF3SO3] might be dependent on compression rate, which needs to be considered as a non-negligible factor for phase transitions of RTILs under high pressure.