Reaction Mechanism and Kinetics Study of CO2 Absorption into [C(2)OHmim][Lys]
Reaction Mechanism and Kinetics Study of CO2 Absorption into [C(2)OHmim][Lys]
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[C(2)OHmim][Lys]吸收CO2的反应机理和动力学研究
DOI：
10.1021/acs.energyfuels.6b01773
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发表时间：
2016
期刊：
影响因子：
5.3
通讯作者：
Li Wei
中科院分区：
文献类型：
--
作者：
Li Sujing;Zhao Chongjian;Sun Cheng;Shi Yun;Li Wei
合成了一种新型亲水性离子液体1-羟乙基-3-甲基咪唑赖氨酸([C2OHmim][Lys])，其CO2吸收容量为1.68molCO2/molIL。用~(13)C核磁共振法成功地分离和检测了三个CO_2与Nat[C2OHmim][Lys]的反应产物。初始浓度为1mol/L的[C2OHmim][Lys]水溶液的吸附容量为1.2604 molCO_2/molIL。用~(13)C核磁共振和湿壁柱研究了[C2OHmim][Lys]水溶液吸附CO_2的反应机理和动力学。在吸收初期，主要化学反应为氨基甲酸酯的生成，属于快速反应。反应级数对[C2OHmim][Lys]的平均值为1.862。在高CO2负荷量(大于0.95molCO2/molIL)条件下，氨基甲酸酯的水解反应为主，介于快速反应和中速反应之间。此外，赖氨酸阴离子上的两个氨基在水解阶段有不同的反应行为，表明与赖氨酸阴离子中的羧基相连的氨基甲酸酯参与了水合反应，而另一个氨基甲酸酯则不参与水合反应。
In this work, a novel hydrophilic ionic liquid (IL) 1-hydroxyethyl-3-methylimidazolium lysine ([C2OHmim][Lys]) with a considerable CO2absorption capacity of 1.68 mol CO2/mol IL was synthesized. Three reaction products between CO2and neat [C2OHmim][Lys] were successfully separated and detected by13C NMR. Meanwhile, the absorption capacity of [C2OHmim][Lys] aqueous solutions with an initial conentration of 1mol/L was 1.2604 mol CO2/mol IL. The reaction mechanism and kinetic study of CO2adsorption into an aqueous solution of [C2OHmim][Lys] were also investigated by using13C NMR and wetted wall column. In the early stage of absorption, the dominant chemical reaction was the formation of carbamate and belonged to the fast reaction. The reaction order was found to be an average value of 1.862 with respect to [C2OHmim][Lys]. At high CO2loading (more than 0.95 mol CO2/mol IL), the hydrolysis of carbamate was the main reaction, and it was between the fast reaction and the medium-speed reaction. Also, the two amino groups on the lysine anion have different reaction behaviors in the hydrolysis stage, suggesting that the carbamate linked to carboxyl in lysine anion participates in the hydration reaction while the other carbamate does not.