What Are Functional Ionic Liquids for the Absorption of Acidic Gases?

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• 作者：Shuhang Ren ; Yucui Hou ; Shidong Tian ; Xiumei Chen ; Weize Wu
• 刊名：The Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：February 28, 2013
• 年：2013
• 卷：117
• 期：8
• 页码：2482-2486
• 全文大小：224K
• 年卷期：v.117,no.8(February 28, 2013)
• ISSN：1520-5207

文摘

As a kind of novel and efficient material, ionic liquids (ILs) are used for capture of acidic gases including SO₂ and CO₂ from flue gas. Due to very low content of acidic gases in flue gas, it is important to find functional ILs to absorb the acidic gases. However, up to now, there is no criterion to distinguish if the ILs are functional or not before use, which greatly influences the design of functional ILs. In this work, a series of ILs were synthesized and used to determine functional or normal ILs for the capture of acidic gases. It has been found that the pK_a of organic acids forming the anion of ILs can be used to differentiate functional ILs from normal ILs for the capture of acidic gases from flue gas. If the pK_a of an organic acid is larger than that of sulfurous acid (or carbonic acid), the ILs formed by the organic acid can be called functional ILs for SO₂ (or CO₂) capture, and it can have a high absorption capacity of SO₂ (or CO₂) with low SO₂ (or CO₂) concentrations. If not, the IL is just a normal IL. The pK_a of organic acids can also be used to explain the absorption mechanism and guide the synthesis of functional ILs.