| Summary: | 碩士 === 南臺科技大學 === 化學工程與材枓工程系 === 106 === Carbon dioxide is one of the most serious greenhouse gases causing global warming. Therefore the reduction of the emission of carbon dioxide is of great importance globally. Currently the absorption of carbon dioxide is the primary approach for CO2 reduction, where ionic liquids are one of the potential absorbents. In this study different methods for the preparation of amino-acid based ionic liquids were investigated. [Bmim][Cl] was used as a starting material in all synthesis routes. For the synthesis of [Bmim][Cl], excess chlorine butane was added to 1-methylimidazole in a reactor at 80 °C for two days. The resulting [Bmim][Cl] has a purity exceeding 99%. [Bmim][Ac] was then prepared by adding acetic acid or acetate salts to [Bmim][Cl]. The chemical structure of ionic liquids was identified by proton NMR, while the chloride content was determined by the silver nitrate titration method. The best synthesis method to prepare [Bmim][Ac] is to add acetate salts to [Bmim][Cl], due to the rapid reaction rate and the high conversion.
The time variation of the carbon dioxide absorption in ionic liquids was recorded by a home-made device, where the uptake was determined by measuring the change of sample weight. The desorption process was recorded in a silimar way instead of using a nitrogen purge at elevated temperatures. Among all the amino-acid based ionic liquids, [Bmim][MET] had the largest uptake after 2-h absorption, and the initial absorption rate was faster than other amino-acid ionic liquids. For desorption, the weight loss of all ionic liquids was close to or greater than the adsorbed amounts. The cyclic absorption/desorption experiment shows that [Bmim][Ac] is still active after a long term adsorption/desorption operation while the amino-acid based ionic liquids may suffer thermal degradation during desorption.
|
|---|
