Yasaka Yoshiro, Saito Yuma, Kimura Yoshifumi
Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, Kyotanabe, Kyoto, 610-0321, Japan.
Present Address: Faculty of Natural System, Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan.
Chemphyschem. 2018 Jul 5;19(13):1674-1682. doi: 10.1002/cphc.201701324. Epub 2018 Apr 24.
The mechanism of CO absorption by a formate ionic liquid, [P ]HCOO, was studied by Raman spectroscopy. The band area for the symmetric CO stretching of the formate anion linearly decreases with the CO loading. From the slope of the decrease, 1 : 1 stoichiometry is proven between CO and the formate anion. The result favors the mechanism we proposed in a preceding work [J. Chem. Eng. Data 61, 837 (2016)]: HCOO +CO +H O→HCOOH+HCO →[HCOOH…HCO ]. Further support for the mechanism is obtained by the observation of antisymmetric vibration of CO for the proposed hydrogen-bonded complex between HCOOH and HCO . The bands appeared as a doublet (1677 and 1730 cm ) as this complex has two carbonyl groups. Based on DFT calculations, the [HCOOH…HCO ] complex is supposed to be the most abundant form of chemisorbed CO .
通过拉曼光谱研究了甲酸根离子液体[P]HCOO吸收CO的机理。甲酸根阴离子对称CO伸缩振动的谱带面积随CO负载量线性降低。根据降低的斜率，证明CO与甲酸根阴离子之间的化学计量比为1∶1。该结果支持了我们在之前的工作[《化学工程数据杂志》61, 837 (2016)]中提出的机理：HCOO + CO + H₂O→HCOOH + HCO₃⁻→[HCOOH…HCO₃⁻]。通过观察HCOOH与HCO₃⁻之间形成的氢键复合物中CO的反对称振动，进一步支持了该机理。由于该复合物有两个羰基，谱带呈现为双峰（1677和1730 cm⁻¹）。基于密度泛函理论计算，[HCOOH…HCO₃⁻]复合物被认为是化学吸附CO的最主要形式。
