Absorption And Conversion Of Nitric Oxide And Carbon Dioxide Using Ionic Liquids And Deep Eutectic Solvents

The emission of nitrogen oxides（NOx）and carbon dioxide（CO₂）cause a harm to environment and human.The current denitration technology has some problems,such as corrosion of equipment,consumption of valuable ammonia（NH₃）and waste of NOx resource.With the continuous promotion of China’s strategic goals of“dual carbon”,the hydrogenation of captured CO₂ into fuels and chemicals had been attracting wide attention.The current CO₂ capture and utilization technology has the problems of high absorbent viscosity,harsh reaction conditions and so on.In view of this,thesis explores the synergistic effect of functional ionic liquids（FILs）and deep eutectic solvents（DESs）with catalyst to efficiently convert absorbed NO and CO₂ into useful chemicals,realizing emission reduction of gases and effective utilization of resources.The main research contents and results are as follows:（1）A proper ionic liquid catalytic system was screened to catalyze the hydrogenation of NO to NH₃,and the results showed that tetraethylenepentamine imidazole salt（[TEPA][Im]）and Pd/C exhibited the best catalytic activity.[TEPA][Im]is alkaline,while NH₃ is insoluble in the ionic liquid,which improves the yield of NH₃.The catalyst has a synergistic effect with[TEPA][Im],which is conducive to catalytic hydrogenation of NO.The yield of NH₃ under different experimental conditions were explored,it was found that the yield of NH₃ reached 71%at a reaction temperature of 100^oC and an H₂ pressure of 0.5 MPa,a water content of 10 wt%,a reaction time of 9 h.The ionic liquid catalytic system showed good catalytic performance after being recycled for six times.The interaction between[TEPA][Im]and NO was studied by molecular dynamics simulation and infrared spectroscopy.The possible reaction mechanism of NO hydrogenation to NH₃ over[TEPA][Im]-Pd/C catalyst was proposed.（2）Low viscosity deep eutectic solvents were synthesized by using N-carbarmimidoylacetamide（AG）as a hydrogen bond acceptor and ethylene glycol（EG）as a hydrogen bond donor for CO₂ absorption.Firstly,the absorption effect of AG:EG on CO₂ was investigated.The results showed that AG:EG（1:5,molar ratio）had a solubility of 0.11 g CO₂/g DES at 40^oC and 0.1 MPa CO₂.The mechanism of CO₂ absorption by AG:EG was investigated by infrared and nuclear magnetic detection.It was found that the hydroxyl group of ethylene glycol is seized hydrogen protons by N-carbarmimidoylacetamide,the O^-formed is the site of action for CO₂ absorption.The synergistic effect between catalysts and the deep eutectic solvents was proved by screening efficient catalytic systems.AG:EG-Pd/C catalytic system showed high catalytic performance for CO₂hydrogenation conversion.The effects of different experimental conditions on the products of CO₂ hydrogenation were explored,the yield of formic acid reached 78%and methanol yield reached 20%under the conditions of80^oC,1 h and an H₂ pressure of 8 MPa.When Pd（PPh₃）₄ was added,the yield of methanol reached 70%under the conditions of 24 h.Based on experimental data,infrared and nuclear magnetic analysis,the possible reaction mechanism of CO₂ hydrogenation catalyzed by AG:EG-Pd catalytic system was proposed.