Organic liquid CO2 capture agents with high gravimetric CO2 capacity

Abstract

We report a new class of CO 2 binding organic liquids that chemically capture and release CO 2 much more efficiently than aqueous alkanolamine systems. Mixtures of organic alcohols and amidine/ guanidine bases reversibly bind CO 2 chemically as liquid amidinium/guanidinium alkylcarbonates. The free energy of CO 2 binding in these organic systems is very small and dependent on the choice of base, approximately À9 kJ mol À1 for DBU and Barton's base and +2 kJ mol À1 for 1,1,3,3tetramethylguanidine. These CO 2 capturing agents do not require an added solvent because they are liquid, and therefore have high CO 2 capacities of up to 19% by weight for neat systems, and slightly less when dissolved in acetonitrile. The rate of CO 2 uptake and release by these organic systems is limited by the rate of dissolution of CO 2 into and out of the liquid phase. Gas absorption is selective for CO 2 in both concentrated and dilute gas streams. These organic systems have been shown to bind and release CO 2 for five cycles without losing activity or selectivity.

Chemisorption of air CO2 on cellulose: an overlooked feature of the cellulose/NaOH(aq) dissolution system

“…In the light of the extensively reported ability of DBU to capture CO 2 in the presence of H-donors (Heldebrant et al , 2008Jessop et al 2005;Yang et al 2011;Mizuno et al 2012;Carrera et al 2015;Rajamanickam et al 2015), these observations could be interpreted as indicative of CO 2 interactions with cellulose/NaO-H(aq) along with changes in the dissolved state stability.…”

Effects of Bonding Types and Functional Groups on CO2 Capture using Novel Multiphase Systems of Liquid-like Nanoparticle Organic Hybrid Materials

“…Ionic liquids can be synthesized with task-specific functional groups (e.g., amine groups for CO 2 capture), and they can also possess interesting features such as reversible and phase changing behaviors. 21 The current drawbacks of ionic liquids as CO 2 capture media include their complex synthesis and purification steps, and high cost.Considering these limitations of CO 2 capture solvents, a new class of CO 2 capture medium named nanoparticle organic hybrid materials (NOHMs) has been formulated. Depending on the selection of organic materials, NOHMs can be synthesized in various forms: liquid-like solvent, solid sorbent or gel-like materials.…”

Novel High Capacity Oligomers for Low Cost CO2 Capture

“…153, 154 The free energy of CO 2 binding is relatively small (-9 kJ/mol for DBU and even smaller for guanidines) and slightly depends on the length alcohol's hydrocarbon radical but decreases from linear to iso radicals (tert-BuOH does not react). 154,155 Fatty radicals in Roh (like in hexanol-1) keep the reaction products liquid.…”

“…153 The reaction rate is very high and limited by the rate of mass transport of CO 2 from the gas phase into solution. 154 Stoichiometric mixtures of DBU with alcohols have high CO 2 capacity (up to 19 wt. % for MeOH) and selectivity and can be cycled several times without capacity loss.…”

“…154,155 Fatty radicals in Roh (like in hexanol-1) keep the reaction products liquid. 153 The reaction rate is very high and limited by the rate of mass transport of CO 2 from the gas phase into solution.…”