Application Of Functionalized Ionic Liquids In Fuel Desulfurization And Acid Gas Absorption

In this thesis,functionalized ionic liquids（ILs）are used for extract desulfurization of fuels and the absorption of sulfur dioxide and carbon dioxide.The main research contents were as follows:1.A series of trialkylamine-based protic ionic liquids（PILs）were synthesized and characterized,and their extraction desulfurization for thiophene（TH）,benzothiophene（BT）,and dibenzothiophene（DBT）in model oil was carried out.Effects of PIL species,extraction time,temperature,PIL dosage,and initial sulfuric concentration on desulfurization efficiency were investigated.Experimental results showed that the PILs exhibited higher extraction ability for TH,BT,and DBT as compared to the reported ILs.Under optimal conditions,the removal efficiency of TH,BT,and DBT using tris（3,6-dioxaheptyl）ammonium salicylate（[TDA][SA]）as extractant was 72.68%,76.31%,and 83.94%,respectively.Finally,the suggested PIL can be easily regenerated and reused via a backextraction process.After 5 extraction cycles,the removal efficiency has no noticeable decrease.With advantages such as higher desulfurization efficiencies,cheap and easily obtained raw materials and simple synthetic process,this study will provide new green solvents for extraction desulfurization process of fuels.2.Deep eutectic solvents（DESs）were synthesized by using pyridine derivatives,aminopyridine or hydroxypyridine,as the hydrogen bond donor（HBD）with common quaternary ammonium salt ionic liquids.The influences of composition,temperature and pressure on SO₂ absorption performance were systematically investigated.The results showed that the studied DESs exhibited an attractive absorption behavior for SO₂,especially low concentration SO₂.Amim Cl/2-NH₂Py（2:1）could capture 1.261,0.535,0.281,and 0.126 g SO₂/g DESs at 101.3k Pa,10k Pa,2k Pa and 0.5k Pa pressure,respectively,surpassing that of most absorbents/adsorbents previously reported.Moreover,the absorption mechanism studied by FTIR and NMR indicated that the efficient absorption of SO₂ was ascribed to the chemical interaction between the pyridine nitrogen atom and SO₂.3.A series of protonic ionic liquids（PILs）based on hydroxyl-containing diaminoamines were synthesized,with different carboxylic acids as anions and used to absorb carbon dioxide.The effects of different types of amino cations and different carboxylic acid anions and temperature on absorption results were studied.The results show that aminoethylethanolamin caprylate[HEEDA][Oc]at 30℃has a good absorption capacity（0.53 mol CO₂/mol PIL）.Desorption can be achieved by passing nitrogen at 80℃,and there is no significant change in the absorption amount after 5 cycles.In addition,FTIR and NMR studies of the absorption mechanism indicate that PIL absorbs CO₂ to form carbamate,which is a chemical absorption.