Protic ionic liquids with low viscosity for efficient and reversible capture of carbon dioxide

Abstract

Protic ionic liquids (PILs) are considered as potential solvents for CO 2 capture due to their simple synthetic routes and unique properties. In this work, three low viscous PILs, tetramethylgunidinium imidazole ([TMGH][Im]), tetramethylgunidinium pyrrole ([TMGH][Pyrr]) and tetramethylgunidinium phenol ([TMGH][PhO]) were synthesized and the effect of anions, temperature, CO 2 partial pressure and water content on CO 2 absorption performance of PILs was also systematically studied. It was found that the PILs with larger basicity show higher CO 2 absorption capacity, and [TMGH][Im] simultaneously shows relatively high absorption rate and CO 2 absorption capacity of 0.154 g CO 2 /g IL at 40 ℃, 1 bar. The addition of H 2 O has a positive effect on gravimetric absorption capacity of CO 2 at the range of 0-20 wt% H 2 O, and the highest capacity of 0.186 g CO 2 /g IL was achieved as the water content was 7 wt%. In-situ FTIR, 13 C NMR and theoretical calculations verified that more stable bicarbonate are produced during CO 2 absorption by [TMGH][Im]-H 2 O system. However, neat [TMGH][Im] can react with CO 2 to form the reversible carbamate, leading to excellent recyclability after four absorption-desorption cycles. The results implied that neat [TMGH][Im] shows great potentials in CO 2 absorption applications.

CO2 Capture in Biocompatible Amino Acid Ionic Liquids: Exploring the Reaction Mechanisms for Bimolecular Absorption Processes

“… 35 This explains why the high viscosity of these fluids is an issue and, at the moment, a key factor that severely limits their practical usability. 41 , 42 …”

Weak Bonds Joint Effects Catalyze the Cleavage of Strong C−C Bond of Lignin‐Inspired Compounds and Lignin in Air by Ionic Liquids

“…Absorption of O 2 : The experimental setup for O 2 absorption followed the procedures according to previous work. [29] 9.9908 g of ILs was placed in a glass container with an inner diameter of 2 cm, which was placed in the water bath at 353 K (the standard uncertainty of temperature is � 0.1 K) at atmosphere. O 2 was bubbled through the IL at a flow rate of 140 mL min À 1 , and the amount of absorbed O 2 was measured by an electronic balance with an accuracy of � 0.1 mg.…”

“…Absorption of O 2 : The experimental setup for O 2 absorption followed the procedures according to previous work [29] . 9.9908 g of ILs was placed in a glass container with an inner diameter of 2 cm, which was placed in the water bath at 353 K (the standard uncertainty of temperature is ±0.1 K) at atmosphere.…”

Cholinium amino acid-based ionic liquids

“…A possible alternative to the ethanolamine-based approach is the use of amine-functionalized ILs which react with CO 2 molecules with the formation of carbamate species and producing improved reaction stoichiometries (Camper et al 2008 ; Vijayraghavan et al 2013 ; Li et al 2019 ). This method tends to cause large changes in solvent viscosity, yet this can be circumvented via counterions that do not promote the formation of H-bonded networks or by water addition.…”