Highly efficient CO 2 absorption was realized through formation of zwitterionic adducts, combining synthetic strategies to ionic liquids (ILs) and coordination. Download game mission impossible 4 jar gasket. The essence of our strategy is to make use of multidentate cation coordination between Li + and an organic base. Also PEG-functionalized organic bases were employed to enhance the CO 2-philicity. The ILs were reacted with CO 2 to form the zwitterionic adduct. Coordination effects between various lithium salts and neutral ligands, as well as the CO 2 capacity of the chelated ILs obtained were investigated. For example, the CO 2 capacity of PEG 150MeBu 2N increased steadily from 0.10 to 0.66 (mol CO 2 absorbed per mol of base) through the formation of zwitterionic adducts being stabilized by Li +.

Introduction Carbon capture and sequestration (CCS) from flue gas formed by combustion of fossil fuel is a critical part of efforts directed towards the stabilization of atmospheric greenhouse gas levels []. In recent years, there has been intense research worldwide aimed at the development of various processes and technologies for efficient CO 2 capture. These efforts include the development of liquid and solid absorbents and membranes [–]. Ionic liquids (ILs), which have attractive properties such as negligible vapor pressure, a wide liquid temperature ranges, good thermal stability, high ionic conductivity, and versatile solvation properties [–], can be designed for task-specific applications through the smart choice of the respective cations and/or anions. Application fields include green solvents for synthesis [,–], efficient catalysts in organic synthesis [,–], media for advanced separation [–], novel electrolytes for energy applications [–], and efficient absorbents for gas separation [,–].

In particular, amino-functionalized IL [APBIm][BF 4] (1-aminopropyl-3-butylimidazolium tetrafluoroborate) and ILs being composed of amino acid (AA) anions and phosphonium or ammonium cations were developed for efficient CO 2 chemisorption [,–]. Binary absorbents derived from superbases together with various non-volatile weak proton donors such as hydroxy-functionalized ILs, imidazolium ILs, fluorinated alcohol, imidazole and phenol, were also found to be efficient liquid absorbents allowing for reversible CO 2 chemisorption [–].

Exp.#2-1 MASSACHUSETTS INSTITUTE OF TECHNOLOGY DEPARTMENT OF CHEMISTRY 5.32 Intermediate Chemical Experimentation EXPERIMENT #2: QUALITATIVE ORGANIC ANALYSIS. Efficient CO 2 capture by tertiary amine-functionalized ionic liquids through Li. Cation coordination between Li + and an organic. De la Fuente J C, Mindrup E M.

In general, two absorbent molecules are involved to react with one CO 2 molecule generating ammonium carbamate () or ammonium alkyl formate (). Hence, increasing the 1:2 (CO 2:absorbent molecule) stoichiometry for the CO 2 capacity to 1:1 is an essential prerequisite for a breakthrough in absorption techniques []. In this respect, task-specifically designed absorbents have been successfully synthesized from AAs and applied for 1:1 CO 2 capture through a carbamic acid formation pathway (, step 1).

Notably, equimolar CO 2 absorption was obtained using task-specific ionic liquids (TSILs) with the phosphonium cation containing long alkyl chains and anions derived from AAs (prolinate and methioninate) [], or AA salts with bulky N-substituents in polyethylene glycol (PEG) solution []. However, procedures for the preparation of ILs usually include complicated purification procedures or the use of volatile organic solvents (e.g., toluene, acetonitrile).

Recently, Wang et al. Developed novel alkanolamine-based ILs through multi-dentate cation coordination between alkanolamine and Li + for reversible CO 2 capture, by simple mixing of equimolar amounts of alkanolamines with LiNTf 2 []. The strong complexation of alkali metal cations by crown ethers could be used to achieve equimolar CO 2 absorption in systems containing crown ethers and easily available alkali metal salts of amino acids, resulting in the respective carbamates (onium salts) [].

Reactions of CO 2 with amino-group containing absorbents (a), base/proton donor binary system (b) or strong organic base (c). As previously reported, strong amidine and guanidine bases such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) can form the base-CO 2 zwitterionic adduct in a 1:1 manner under strictly anhydrous conditions () [–]. Herein, we present such a method combining the formation of ILs and coordination to achieve equimolar CO 2 capture through zwitterionic adduct formation. The essence of our strategy is to make use of the multisite coordination interaction between Li + and organic bases or PEG-functionalized organic bases.

The readily prepared ILs were reacted then with CO 2 to form intramolecular zwitterionic adducts. Entry Ionic liquid Δ H f/kcal mol −1 b CO 2 capacity c 1 [PEG 150MeLi][NTf 2] −100.94 0.09 (0.9%) 2 [OctImLi][NTf 2] −56.49 0.11 (1.0%) 3 [PEG 150MeImLi][NTf 2] −91.17 0.16 (1.4%) 4 [PEG 150MeNH 2Li][NTf 2] −89.39 0.45 (4.4%) 5 [TMGLi][NTf 2] −41.59 0.65 (7.1%) 6 [OctTMGLi][NTf 2] −47.79 0.80 (6.8%) 7 [PEG 150MeTMGLi][NTf 2] −106.56 0.89 (7.1%) 8 OctBu 2N/LiNTf 2 – – 9 PEG 150MeBu 2N – 0.10 (1.6%) 10 [PEG 150MeBu 2NLi][NTf 2] −96.26 0.66 (5.2%) 11 [PEG 150MeBu 2NLi][SO 3CF 3] −96.26 0.61 (6.2%) 12 [DBULi][NTf 2] −60.22 0.50 (5.0%) 13 [DBNLi][NTf 2] −60.50 0.75 (8.0%). AIonic liquids were prepared by mixing of a neutral ligand with LiNTf 2 in 1:1 molar ratio. CO 2 absorption was carried out at 25 °C and absorption equilibrium was reached within 20 min. BEnergy of the gas phase reaction between the neutral ligand and Li +, was calculated with DFT, using the B3PW91 functional with the 6-311++G (d,p) basis set as implemented in the Gaussian 09 program package.