Two‐Dimensional Infrared Correlation Spectroscopy and Principal Component Analysis on the Carbonation of Sterically Hindered Alkanolamines

Abstract

Despite the academic and industrial importance of the chemical reaction between carbon dioxide (CO(2)) and alkanolamine, the delicate and precise monitoring of the reaction dynamics by conventional one-dimensional (1D) spectroscopy is still challenging, due to the overlapped bands and the restricted static information. Herein, we report two-dimensional infrared correlation spectroscopy (2D IR COS) and principal component analysis (PCA) on the reaction dynamics of a sterically hindered amine, 2-[(1,1-dimethylethyl)amino]ethanol (TBAE) and CO(2). The formation of carbonate rather than carbamate species, which contribute to the unusual high working capacity of ∼1 mole CO(2) per mole of TBAE at 40 °C, occurs through deprotonation of the hydroxyl group, protonation on the nitrogen atom of the amino group, and formation of a carbonate species due to the steric hindrance of the tert-butyl group. In particular, PCA captures the chemical transition into a carbonate species and the main contributions of ν(CO(2)), ν(OH), ν(C - N), and ν(C=O) bands to the carbonation, while 2D IR COS verifies the interrelation of four bands and their changes. Therefore, these results provide a powerful analytic method to understand the complex and abnormal reaction dynamics as well as the rational design strategy for the CO(2) absorbents.

Computational Modeling and Simulation of CO2 Capture by Aqueous Amines

“…A number of studies have also used IR to provide structural interpretation of products forms. This is based on a simple analysis of characteristic peaks 310,311 and also by a detailed comparison of vibrational spectra to molecular modeling predictions. 197,312,313 The use of Raman spectroscopy is less common than IR.…”

Improving the regeneration of CO2-binding organic liquids with a polarity change

“…PAPER systems include conventional ionic liquids (ILs), 5 amines in ILs, 6 task-specic ILs (TSILs), 5,[7][8][9] nanoparticle organic hybrid materials (NOHMs), 10 phase changing solvents, 11 and alkanolamines and hindered amines in organic co-solvents. [12][13][14] Keeping with this trend, a class of switchable ILs, originally developed by Jessop et al, 15 was specically modied for CO 2 capture. 16 This particular class, referred to as CO 2 -binding organic liquids (CO 2 BOLs) acts like aqueous amines, but uses alcohols in place of water and a non-nucleophilic base in place of nucleophilic primary and secondary amines.…”

Directed Hydrogen Bond Placement: Low Viscosity Amine Solvents for CO2 Capture

“…Alkanolamines dissolved in organic solvents, such as ethylene glycol or alcohols, have been proposed as potential substitutes for aqueous amines. Examples of nonaqueous amine formulations include sterically hindered alkanolamines, − amino alcohol blends like DEA, N -methyl-diethanolamine (MDEA), monomethylethanolamine (MMEA), and diisopropanolamine (DIPA). , In these materials, CO 2 binds through the conventional carbamate mechanism, but significant carbamic acid products have also been observed. , Aminosilicones (GAP) are another nonaqueous solvent system that combine physisorbing siloxane groups with chemisorbing amines. − Amine-based switchable carbamates, such as trialkylsiloxyalkylamines, trialkylsilylpropylamines, , and alkyldiamines, also react reversibly with CO 2 to form liquid carbamate salts. Alkylsiloxyamines and silylamines bind CO 2 via a standard carbamate mechanism while the diamines form zwitterionic carbamates.…”