Viscosity And Density Estimation Of Ionic Liquids And Research Of Fixation Of CO₂Using Ionic Liquids

At present, there is more and more carbon dioxide poured into the atmosphere so thatthe greenhouse effect became increasingly serious. Therefore, the recycling and utilizing ofcarbon dioxide become more and more significant. It is a new method to use functionalionic liquids to recycle carbon dioxide. But the high viscosity of ionic liquids isunfavorable to use. Ionic liquid has good design adjustability, so it will be of greatsignificance to estimate its viscosity before synthesizing the ionic liquid.The reported density, viscosity data for ionic liquids in the references are collectedand analyzed. A group contribution method is introduced to estimate the density andviscosity of pure ionic liquids at different temperatures. The average relative error （ARE）of the viscosity estimation for pure ionic liquids is5.41%, while the ARE for thirteenpure ionic liquids which do not participate in the correlation is5.61%. Furthermore, theaverage relative error （ARE） of the density estimation using the same method for pureionic liquids is5.17%, while the ARE for eight pure ionic liquids which do notparticipate in the correlation is5.91%. The research results show that with thetemperature rising, the viscosity and density of ionic liquids reduced, the structure ofionic liquids can affect the viscosity and density of ionic liquids, and the average relativeerror of using group contribution to estimate the viscosity and the density is less than10%, which is proved to be feasible.Based on the good design adjustability of ionic liquids, two new amino functionalionic liquids are designed and synthetized,[NH₂emim][NH₂CH₂COO] and [NH₂e-mim][CF₃COO]. The structure of two ionic liquids is characterized by IR spectra andHNMR spectra, and the physical properties are also measured, including viscosity,density and conductivity. The absorption rate of carbon dioxide is determined at30℃and0⁰.2MPa, the results show that the absorption rate is increasing as the pressure goesup, and the former absorption is higher than the latter. The CO₂absorption rate of thesynthetizing ionic liquids which contain amino is superior to the traditional organicsolvent and conventional ionic liquids. The results become the basic data of ionic liquidsfor further exploitation and application.