Functionalized Ionic Liquids For Absorption And Conversion Of Carbon Monoxide And Sulfur Dioxide

In recent years,a large number of exhaust gases containing sulfur dioxide?SO₂?and carbon monoxide?CO?are emitted from industrial sources,which attitude a major threat to social and economic development and human health.On the other hand,CO is an important C1 chemical raw material.It is also of great significance to develop efficient CO conversion technology.As a typical representative of green chemistry,ionic liquids?ILs?have unique properties,such as designability,low volatility,excellent solvent capacity,etc.,which are expected to be used as efficient absorbents to capture SO₂ and CO and other gases.However,at present,there are still two major problems to be solved in the absorption of SO₂ and CO by ILs:1.CO gas has a high molecular bond energy,and IL has a weak force on it,resulting in a limited amount of CO absorption;2.The increase of viscosity of ILs after absorption of SO₂ affects the absorption rate of SO₂,and the absorption selectivity of SO₂ and CO₂ is also inefficient.In order to resolve the above problems,two kinds of functional ILs are designed and synthesized in this thesis.Through excellent control of the anion structure of ILs,high-temperature absorption of CO and efficient carbonyl conversion are achieved,and fast and highly selective absorption and separation of SO₂/CO₂ are realized.The detail research contents are as follows:Firstly,bimetal IL[BimH][Cl]-CuCl-ZnCl₂ was designed and synthesized.At80°C and 1 bar,the absorption of CO by[BimH][Cl]-CuCl-ZnCl₂ was as high as 0.078mol mol^-1.The results of high-resolution mass spectrometry and Raman spectroscopy show that the anions in bimetal IL[BimH][Cl]-CuCl-ZnCl₂ are mainly ZnCl₃^-,leading the interaction between cuprous ion and chloride ion weak,make the coordination number of cuprous ion is increased,and the interaction between cuprous ion and CO is strengthened,so that the IL can effectively absorption of CO at high temperature.Furthermore,the bimetal IL also show good recycling performance,the absorption performance has no obvious declined after 12 cycles.Secondly,bimetallic IL[BimH][Cl]-CuCl-ZnCl₂ can also be used as both absorbent and catalyst,the high-efficiency amino-carbonylation of iodobenzene,diethylamine and CO was realized at100°C and 1 bar,and the yield of the major product reached 97%.Secondly,a functional IL of salicylic acid anion was designed and synthesized.The SO₂ molecules were selectively identified and absorbed by the phenolic hydroxyl and carboxyl groups of salicylic acid anion.Under the condition of 20°C and 1 bar,the absorption of SO₂ was 3.58 mol mol^-1,and the absorption of CO₂ was only 0.05 mol mol^-1,making the absorption selectivity of SO₂/CO₂ up to 111.At the same time,the viscosity of the IL decreased dramatically after absorption of SO₂,making the absorption of SO₂ fast and highly selective.The results of high-resolution mass spectrometry,infrared spectrum and nuclear magnetic resonance showed that the absorption of SO₂ destroyed the association hydrogen bond between the molecules of salicylic acid anion,making the viscosity of IL in the absorption system sharply reduced,ensures the rapid absorption of SO₂,and the absorption equilibrium time is only 5 min.