Generation of Superoxide Ion in Pyridinium, Morpholinium, Ammonium, and Sulfonium-Based Ionic Liquids and the Application in the Destruction of Toxic Chlorinated Phenols

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• 作者：Maan Hayyan ; Farouq S. Mjalli ; Mohd Ali Hashim ; Inas M. AlNashef
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：August 15, 2012
• 年：2012
• 卷：51
• 期：32
• 页码：10546-10556
• 全文大小：442K
• 年卷期：v.51,no.32(August 15, 2012)
• ISSN：1520-5045

文摘

Generation of superoxide ion (O₂^{鈥⑩€?/sup>) was carried out in four ionic liquids (ILs) having the same anion, bis(trifluoromethylsulfonyl)imide [N(Tf)₂]鈭?/sup>, and different cations, N-hexylpyridinium [HPy]+, N-methoxyethyl-N-methylmorpholinium [MO1,1O2]+, N-ethyl-N,N-dimethyl-2-methoxyethylammonium [N112,1O2]+, and triethylsulfonium [S222]+. Cyclic voltammetry (CV) and chronoamperometry (CA) electrochemical techniques were used in this investigation. It was found that O₂鈥⑩€?/sup> is not stable in the [HPy]+-based IL. On the other hand, CV showed that the electrochemically generated O₂鈥⑩€?/sup> is stable in [MO1,1O2]+-, [N112,1O2]+-, and [S222]+-based ILs for the time duration of the experiment. The long-term stability of the generated O₂鈥⑩€?/sup> was then investigated by dissolving potassium superoxide (KO₂) in dimethyl sulfoxide (DMSO) in the presence of the corresponding IL. It was found that ILs containing [MO1,1O2]+ and [N112,1O2]+ offer a promising long-term stability of O₂鈥⑩€?/sup> for various reactions to be used for several applications. However, it was found that after 2 h, about 92.5% of the generated O₂鈥⑩€?/sup> in [S222]+ based IL was consumed. The diffusion coefficient and solubility of O₂ in the studied ILs were then determined using CV and CA techniques simultaneously. It was found that diffusion coefficients and CA steady-state currents increase with temperature increases, while the solubility of O₂ decreased. To our best knowledge, this is the first time that morpholinium and sulfoniumbased ILs were utilized as media for chemical and electrochemical generation of O₂鈥⑩€?/sup>. Additionally, the chemically generated O₂鈥⑩€?/sup>, by dissolving KO₂, was then used for the destruction of 2,4-dichlorophenol (DCP) in [MO1,1O2][N(Tf)₂] under ambient conditions. The destruction percentage was higher than 98%. This work represents a novel application of the chemically generated O₂鈥⑩€?/sup> for the destruction of toxic chlorinated phenols in ILs media.}