Synthesis Of Alcohol Amine-choline Chloride Pseudo Ionic Liquid And Its Performance In CO₂ Capture

With the steady increase of CO₂ emissions year by year,the greenhouse effect caused by CO₂ emissions is threatening the survival of mankind.Removal of CO₂ from the environment has become a key issue in preventing global warming and climate change.The most mature post-combustion CO₂ capture technology uses amine aqueous solutions.However,amine-based technology has serious shortcomings,such as amine degradation,high equipment corrosion,high energy consumption for solvent regeneration,and high operating costs.Ionic liquids（ILs）are a very promising alternative absorbent choice to improve the status of post-combustion CO₂ capture and gas separation technologies.People’s widespread interest in ILs stems from the widespread need for environmentally-friendly new green solvents to replace ordinary organic solvents.However,ILs’high cost,air sensitivity,inherent toxicity and high volatile content have restricted their large-scale industrial practice application.Therefore,three kinds of alcoholamine-choline chloride pseudo ionic liquid adsorbents with different molar ratios were designed and synthesized,and their physical and chemical properties,such as melting point,density,viscosity and thermal stability,were determined.To explore its structure and absorption mechanism,and provide theoretical support for the development of new green solvents to capture CO2.The main research contents and conclusions are as follows:（1）Different molar ratios of ethanolamine-choline chloride pseudo ionic liquids,diethanolamine-choline chloride pseudo ionic liquids and N-methyldiethanolamine-choline chloride pseudo ionic liquids were prepared by one-step synthesis.Its structure was characterized by NMR,IR and Raman,and the results showed that there was no chemical change between the hydrogen bond donor and the hydrogen bond acceptor,and the hydrogen bond between the hydrogen bond donor and the hydrogen bond acceptor was the main reason for the formation of the pseudo ionic liquid.（2）The effects of different temperature,molar ratio and gas flow rate on the CO₂capture of the three alcoholamine-choline chloride pseudo ionic liquids were investigated.The results showed that the adsorption capacity of the pseudo ionic liquids decreased gradually with the increase of temperature and gas flow rate,but increased with the increase of hydrogen bond donor ratio.When the reaction temperature was 30℃and the gas flow rate was 80 m L/min,the adsorption capacity of the pseudo ionic liquid（Ch Cl:MEA=1:7）for CO₂ was the largest,which was 0.33325 g/g.（3）The structures of the three alcoholamine-choline chloride pseudo ionic liquids before and after the absorption of CO₂ were characterized by NMR and IR,and it was found that the absorption of CO₂ by the ethanolamine-choline chloride pseudo ionic liquids and diethanolamine-choline chloride pseudo ionic liquids was mainly chemical absorption.The capture of CO₂ by N-methyldiethanolamine-choline pseudo ionic liquid is physical absorption.