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Dive into the research topics where Charles J. Freeman is active.

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Featured researches published by Charles J. Freeman.


Journal of Physical Chemistry Letters | 2016

Dynamic Acid/Base Equilibrium in Single Component Switchable Ionic Liquids and Consequences on Viscosity.

David C. Cantu; Juntaek Lee; Mal Soon Lee; David J. Heldebrant; Phillip K. Koech; Charles J. Freeman; Roger Rousseau; Vassiliki Alexandra Glezakou

The deployment of transformational nonaqueous CO2-capture solvent systems is encumbered by high viscosities even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we present key molecular features that control bulk viscosity. Fast CO2-uptake kinetics arise from close proximity of the alcohol and amine sites involved in CO2 binding in a concerted fashion, resulting in a Zwitterion containing both an alkyl-carbonate and a protonated amine. The population of internal hydrogen bonds between the two functional groups determines the solution viscosity. Unlike the ion pair interactions in ionic liquids, these observations are novel and specific to a hydrogen-bonding network that can be controlled by chemically tuning single molecule CO2 capture solvents. We present a molecular design strategy to reduce viscosity by shifting the proton transfer equilibrium toward a neutral acid/amine species, as opposed to the ubiquitously accepted zwitterionic state. The molecular design concepts proposed here are readily extensible to other CO2 capture technologies.


Green Chemistry | 2016

Structure–property reduced order model for viscosity prediction in single-component CO2-binding organic liquids

David C. Cantu; Deepika Malhotra; Phillip K. Koech; David J. Heldebrant; Feng Zheng; Charles J. Freeman; Roger Rousseau; Vassiliki Alexandra Glezakou

CO2 capture from power generation with aqueous solvents remains energy intensive due to the high water content of the current technology, or the high viscosity of non-aqueous alternatives. Quantitative reduced models, connecting molecular structure to bulk properties, are key for developing structure–property relationships that enable molecular design. In this work, we describe such a model that quantitatively predicts viscosities of CO2 binding organic liquids (CO2BOLs) based solely on molecular structure and the amount of bound CO2. The functional form of the model correlates the viscosity with the CO2 loading and an electrostatic term describing the charge distribution between the CO2-bearing functional group and the proton-receiving amine. Molecular simulations identify the proton shuttle between these groups within the same molecule to be the critical indicator of low viscosity. The model, developed to allow for quick screening of solvent libraries, paves the way towards the rational design of low viscosity water-lean solvent systems for post-combustion CO2 capture. Following these theoretical recommendations, synthetic efforts of promising candidates and viscosity measurement provide experimental validation and verification.


Chemical Engineering Journal | 2011

Performance of Single-Component CO2-Binding Organic Liquids (CO2BOLs) For Post Combustion CO2 Capture

David J. Heldebrant; Phillip K. Koech; James E. Rainbolt; Feng Zheng; Tricia D. Smurthwaite; Charles J. Freeman; Merit Oss; Ivo Leito


Dalton Transactions | 2015

Hydrophobic and moisture-stable metal–organic frameworks

Carlos A. Fernandez; Satish K. Nune; Harsha V.R. Annapureddy; Liem X. Dang; B. Peter McGrail; Feng Zheng; Evgueni Polikarpov; David L. King; Charles J. Freeman; Kriston P. Brooks


Energy & Fuels | 2016

Bench-Scale Testing and Process Performance Projections of CO2 Capture by CO2–Binding Organic Liquids (CO2BOLs) with and without Polarity-Swing-Assisted Regeneration

Feng Zheng; David J. Heldebrant; Paul M. Mathias; Phillip K. Koech; Mukund Bhakta; Charles J. Freeman; Mark D. Bearden; Andy Zwoster


Archive | 2015

Low-Energy Solvents for Carbon Dioxide Capture Enabled by a Combination of Enzymes and Vacuum Regeneration

Sonja Salmon; Charles J. Freeman; Reynolds A. Frimpong; Alan House; Jonathan Slater; Andrew Jones; Novozymes Sonja Salmon; Pm; Erin Yarborough; Megan Beckner Whitener; Uk-Caer Kunlei Liu; Kun Liu; Guojie Qi; Balraj Ambedkar Joe Remias; Pnnl Charles Freeman; Tl; Greg A. Whyatt; Mark D. Bearden; Kayte Denslow; Richard Zheng; Doosan David Fitzgerald; Rafael Vidal; Tania Russell; Scott Hume; Vinay Mulgundmath; Saravanan Swaminathan; Agnieszka Magdalena Kuczynska


Energy Procedia | 2014

Evaluating transformational solvent systems for post-combustion CO2 separations

David J. Heldebrant; Vassiliki Alexandra Glezakou; Phillip K. Koech; Paul M. Mathias; David C. Cantu; Roger Rousseau; Deepika Malhotra; Mukund Bhakta; Mark D. Bearden; Charles J. Freeman; Feng Zheng


Industrial & Engineering Chemistry Research | 2017

Measuring CO2 and N2O Mass Transfer into GAP-1 CO2–Capture Solvents at Varied Water Loadings

Greg A. Whyatt; Andy Zwoster; Feng Zheng; Robert James Perry; Benjamin Rue Wood; Irina Spiry; Charles J. Freeman; David J. Heldebrant


Industrial & Engineering Chemistry Research | 2016

Measuring Nitrous Oxide Mass Transfer into Non-Aqueous CO2BOL CO2 Capture Solvents

Greg A. Whyatt; Charles J. Freeman; Andy Zwoster; David J. Heldebrant


Industrial & Engineering Chemistry Research | 2013

Assessing Anhydrous Tertiary Alkanolamines for High-Pressure Gas Purifications

Paul M. Mathias; Louis V. Jasperson; David VonNiederhausern; Mark D. Bearden; Phillip K. Koech; Charles J. Freeman; David J. Heldebrant

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David J. Heldebrant

Pacific Northwest National Laboratory

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Mark D. Bearden

Pacific Northwest National Laboratory

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Phillip K. Koech

Pacific Northwest National Laboratory

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Feng Zheng

Pacific Northwest National Laboratory

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David C. Cantu

Pacific Northwest National Laboratory

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Roger Rousseau

Pacific Northwest National Laboratory

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Vassiliki Alexandra Glezakou

Pacific Northwest National Laboratory

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Deepika Malhotra

Pacific Northwest National Laboratory

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Andy Zwoster

Battelle Memorial Institute

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Greg A. Whyatt

Pacific Northwest National Laboratory

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