双功能离子液体的合成及二氧化碳捕集性能

Synthesis of Dual-functionalized Ionic Liquid and Application in CO_2 Absorption

采用两步法合成了新型功能化离子液体1-甲氧基乙基-3-甲基咪唑甘氨酸([C_3O_1mim][Gly]),并研究了其对CO_2的吸收性能.利用核磁共振、红外光谱及热重分析等手段进行表征,验证了该离子液体的结构,且发现其具有较高的热稳定性.对比单乙醇胺(MEA),考察了[C_3O_1mim][Gly]在不同温度下对CO_2的捕集能力,结果表明,[C_3O_1mim][Gly]在40℃下的吸收容量可达1.26 mol CO_2/mol IL,远高于MEA,这表明[C_3O_1mim][Gly]对CO_2具有良好的吸收能力,吸收容量随着温度升高而降低.该离子液体同时具有良好的循环稳定性,进行5次吸收解吸操作后仍可保持较高的CO_2吸收量.对该离子液体吸收CO_2进行了动力学研究,结果表明,Pseudo-second-order模型能够较好地描述该吸收过程.

A new bifunctional ionic liquid was prepared,characterized and applied in the absorption and desorption of CO_2. First,1-methoxyethyl-3-methyl imidazolium glycinate（ [C_3O_1 mim][Gly]） was synthesized by two-step method. The molecular structure was characterized and confirmed by1 H,^（13）C nuclear magnetic resonance（ NMR） and Fourier transform infrared（ FTIR） spectroscopy. And thermogravimetric（ TG） analysis suggested that [C_3O_1 mim][Gly] had good thermal stability. Then,compared to monoethanolamine（ MEA）,the CO_2 absorption capacity of [C_3O_1 mim][Gly]was studied in the range of 25—100 ℃ at normal pressure.By computation,the CO_2 absorption capacity can reach 1. 26 mol CO_2/mol IL at 40 ℃,which is greatly higher than that of monoethanolamine（ 0. 54 mol CO_2/mol MEA）. And absorption capacity of CO_2 in[C_3O_1 mim][Gly] would decrease with the increase of temperature from 40 ℃ to 100 ℃. Furthermore,the ionic liquid exhibited excellent reversibility and CO_2 absorption capacity can be maintained after 5 times of absorption-desorption circulation. Finally,the absorption kinetics of CO_2 in [C_3O_1 mim][Gly] was studied at 40 ℃. And Pseudo-second-order model is good to describe CO_2 absorption in [C_3O_1 mim][Gly].