Reinventing Design Principles for Developing Low‐Viscosity Carbon Dioxide‐Binding Organic Liquids for Flue Gas Clean Up

Abstract

Anthropogenic CO emissions from point sources (e.g., coal fired-power plants) account for the majority of the greenhouse gases in the atmosphere. Water-lean solvent systems such as CO -binding organic liquids (CO BOLs) are being developed to reduce the energy requirement for CO capture. Many water-lean solvents such as CO BOLs are currently limited by the high viscosities of concentrated electrolyte solvents, thus many of these solvents have yet to move toward commercialization. Conventional standard trial-and-error approaches for viscosity reduction, while effective, are time consuming and economically expensive. We rethink the metrics and design principles of low-viscosity CO -capture solvents using a combined synthesis and computational modeling approach. We critically study the effects of viscosity reducing factors such as orientation of hydrogen bonding, introduction of higher degrees of freedom, and cation or anion charge solvation, and assess whether or how each factor affects viscosity of CO BOL CO capture solvents. Ultimately, we found that hydrogen bond orientation and strength is the predominant factor influencing the viscosity in CO BOL solvents. With this knowledge, a new CO BOL variant, 1-MEIPADM-2-BOL, was synthesized and tested, resulting in a solvent that is approximately 60 % less viscous at 25 mol % CO loading than our base compound 1-IPADM-2-BOL. The insights gained from the current study redefine the fundamental concepts and understanding of what influences viscosity in concentrated organic CO -capture solvents.

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

“…These include nanomaterial organic hybrids (NOHMs), 29 task-specific protic 30 and conventional ionic liquids, 31 phase-change solvents, 32,33 binding organic liquids (CO 2 BOLs). 34,35 Nearly all of these water-lean solvent systems are projected to be more efficient than aqueous amines but have been limited by nonlinear increases in solvent viscosity during CO 2 uptake. Recently, we showed that, after CO 2 -complexation, singlecomponent CO 2 BOLs do not exist as purely zwitterionic species but rather exist in a dynamic equilibrium between two CO 2 -bound states, an alkyl carbonic acid and a zwitterionic alkylcarbonate.…”

“…This can be achieved by minimizing the water content, thus enabling regeneration temperatures below 100 °C where low-grade heat could be used to regenerate the solvent. − Many solvent classes have been developed based on these principles. These include nanomaterial organic hybrids (NOHMs), task-specific protic and conventional ionic liquids, phase-change solvents, , and our own CO 2 -binding organic liquids (CO 2 BOLs). , Nearly all of these water-lean solvent systems are projected to be more efficient than aqueous amines but have been limited by nonlinear increases in solvent viscosity during CO 2 uptake.…”

Molecular‐Level Overhaul of γ‐Aminopropyl Aminosilicone/Triethylene Glycol Post‐Combustion CO2‐Capture Solvents

“…The VLE measurements were performed according the PTx cell principle . A custom test cell developed in‐house was used for simultaneous VLE, kinetics, and physical property measurements of non‐aqueous solvents using less than 50 mL of sample.…”

Diamine based water‐lean CO2 solvent with extra high cyclic capacity and low viscosity

“…CO 2 BOL (IPADM-2BOL). [30][31][32] which is a novel CO 2 binding organic liquid with high cyclic capacity but high viscosity, was chosen to illustrate the impact of viscosity on sensible heat together with ENH-5%H 2 O (Fig. 5).…”