The Synthesis Of New Containing Amino Dual-core Basic Ionic Liquid And Used To Absorb CO₂

In recent years,the greenhouse effect caused by the global warming has caused more and more attention.CO₂ as the main greenhouse gases,for its recovery has an important significance.There are many methods that in view of the CO₂ recycling,including absorption,pressure swing adsorption,membrane separation,biological separation process and so on.Among them the absorption is one of the most mature and widely used.Generally it can be divided into physical absorption and chemical absorption.The chemical absorption method has a great advantage in absorb CO₂,but,at the same time,it also has some disadvantages.Ionic liquids with low melting point,high thermal stability,high solubility,adjustable structure,negligible vapor pressure,is the emerging of the removal of CO2 reversible absorber.Because the conventional ionic liquids using physical action’s ability to absorb CO₂ is limited,so the development of new effective functionalized ionic liquids is imminent.Compared with the former,the latter action principle is the use of chemical absorption.At the same time,because the process is reversible and can be recycled,so as to realize the efficient absorption of CO₂ and the process of the economy.Have been made in this paper the mononuclear ionic liquid[NH2-C3mim][Br]on the basis of the synthesis of a new kind of containing amino dual-core basic ionic liquids（CH2）2[NH2-C3mim][Br]2,to improve absorptive capacity of CO₂.This paper synthesis of the single-core ionic liquid and dual-core ionic liquid which two kinds of amine functionalized ionic liquids have the same functional groups,respectively are[NH₂-C₃mim][Br]and（CH₂）₂[NH₂-C₃mim]₂[Br]₂.Then characterization the functional groups by using ¹HNMR、¹³CNMR and FT-IR.The results showed that the synthesis of ionic liquids is consistent with the assumptions.Thermal gravimetric analysis results showed that ionic liquid thermal stability is good before 300℃.The cation of single-core ionic liquids[NH₂-C₃min]⁺and the ion pairs of single-core ionic liquids[NH2-C3min][Br],and the ion pairs of dual-core ionic liquids（CH₂）₂[NH₂-C₃min]₂[Br]₂,and the process of absorbing CO₂ by two kinds of ionic liquids at molecular level were studied systematically by B3LYP/6-311++G（d,p）of density functional theory.The structure optimization,frequency analysis and energy calculation were obtained,and charge distribution of the stable configurations were analyzed.The stable geometry and electron configurations were obtained.The use of the synthesis of ionic liquids for CO₂ absorption experiment,by changing the absorption conditions,including the absorption time,temperature,pressure,concentration,etc.,to determine the absorption experiment the optimum absorption conditions.Namely single-core ionic liquids in theory the most molar absorption of CO₂ is0.5 mol_CO2/mol_IL,and the experimental results showed that the dual-core ionic liquid molar absorption did more than single-core ionic liquid,but not increase exponentially,probably is between 1.6¹.7 times.By the analysis,should be dual-core ionic liquid viscosity is larger,and ionic liquid in the hydrogen bonds may have a certain influence.Ionic liquid become rich after absorpting CO2,the vacuum desorption under 343.15 K for two hours,after four absorption desorption cycle,absorption rate is still above 90%,the results showed that the functional ionic liquid can be recycled.