Synthesis And Carbon Dioxide Adsorption Behavior Of Protic Ionic Liquids

The emission of carbon dioxide has attracted more and more attention, because CO2 is a kind of main greenhouse gas that affects economics and environment. The study on the capture of CO2 is highly important. Recently, ionic liquid provides a new chance to develop new method for the capture of CO2 because of their unique properties including low pressure, wide liquid range, high stability, good tunability, and excellent solubility. The study on how to design new functionalized ionic liquids for efficient, rapid, and economical CO2 capture is a hot topic for carbon capture.Several kinds of protic basic ionic liquids were prepared from simple superbase and weak acid such as imidazole making use of the neutralization of acid and base. Their structures were characterized using NMR and IR methods. The properties of these protic ionic liquids including conductivity, viscosity, and thermal stability were investigated. The results indicate that the thermal stability of these protic ionic liquids is low in comparison with traditional aprdtic ionic liquids.The capture of CO2 by these protic basic ionic liquids was investigated in chapter 3, which indicates these ionic liquids exhibit excellent CO2 capture, where about one mole CO2 per mole ionic liquid can be achieved. The weight percent of these ionic liquids is very high due to their low molecular weight, which is higher than 16 percent. To the best of our knowledge, these ionic liquids exhibit the highest CO2 capacity. It is interesting that the absorption rate by these protic ionic liquids is very fast because their viscosities are low during the capture of CO2.Furthermore, the stability of these protic ionic liquids before and after the capture of CO2 was investigated using TGA method, indicating the performance of CO2 desorption is good. The study on the recycles shows the capture of CO2 by these protic ionic liquids is reversible. Finally, the mechanism on CO2 capture by these protic ionic liquids was investigated through NMR and IR method. The IR results show that a new peak produced after CO2 was capture by a kind of protic ionic liquid [DBUH][lm], which can be attributed the carbon peak of the carbamate group.