Equimolar Carbon Dioxide Absorption by Ether Functionalized Imidazolium Ionic Liquids
作者:Pankaj Sharma、Sang-Do Park、Ki-Tae Park、Soon-Kwan Jeong、Sung-Chan Nam、Il-Hyun Baek
DOI:10.5012/bkcs.2012.33.7.2325
日期:2012.7.20
A series $[C_3Omim]$[X] of imidazolium cation-based ILs, with ether functional group on the alkyl side-chain have been synthesized and structure of the materials were confirmed by various techniques like $^1H$, $^13}C$ NMR spectroscopy, MS-ESI, FTIR spectroscopy and EA. More specifically, the influence of changing the anion with same cation is carried out. The absorption capacity of $CO_2$ for ILs were evaluated at 30 and $50^\circ}C$ at ambient pressure (0-1.6 bar). Ether functionalized ILs shows significantly high absorption capacity for $CO_2$. In general, the $CO_2$ absorption capacity of ILs increased with a rise in pressure and decreased when temperature was raised. The obtained results showed that absorption capacity reached about 0.9 mol $CO_2$ per mol of IL at $30^\circ}C$. The most probable mechanism of interaction of $CO_2$ with ILs were investigated using FTIR spectroscopy, $^13}C$ NMR spectroscopy and result shows that the absorption of $CO_2$ in ether functionalized ILs is a chemical process. The $CO_2$ absorption results and detailed study indicates the predominance of 1:1 mechanism, where the $CO_2$ reacts with one IL to form a carbamic acid. The $CO_2$ absorption capacity of ILs for different anions follows the trend: $BF_4$ < DCA < $PF_6$ < TfO < $Tf_2N$. Moreover, the as-synthesized ILs is selective, thermally stable, long life operational and can be recycled at a temperature of $70^\circ}C$ or under vacuum and can be used repeatedly.
一系列基于咪唑鎓阳离子的离子液体$[C_3Omim]$[X],其中烷基侧链上具有醚功能团,已经合成并通过多种技术如$^1H$、$^13}C$核磁共振波谱、MS-ESI、FTIR光谱和元素分析确认了其结构。更具体地,通过改变相同阳离子下的阴离子进行了影响研究。在常压下(0-1.6 bar)和30°C及$50^\circ}C$下评估了离子液体对$CO_2$的吸收能力。具有醚功能化的离子液体显示出显著高的$CO_2$吸收能力。一般而言,随着压力增加,离子液体的$CO_2$吸收能力增加,而随着温度升高则降低。获得的结果显示,吸收能力在$30^\circ}C$下达到约0.9摩尔$CO_2$每摩尔离子液体。通过FTIR光谱和$^13}C$核磁共振波谱研究了与$CO_2$相互作用的最可能机制,结果表明$CO_2$在醚功能化离子液体中的吸收是一个化学过程。$CO_2$吸收结果和详细研究指出1:1机制的主导性,其中$CO_2$与一个离子液体反应形成氨基甲酸。对于不同阴离子的离子液体,$CO_2$吸收能力遵循以下趋势:$BF_4$ < DCA < $PF_6$ < TfO < $Tf_2N$。此外,合成的离子液体具有选择性、热稳定性和长寿命操作,可以在$70^\circ}C$或真空下回收并重复使用。