Charles J. Freeman
Pacific Northwest National Laboratory
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Featured researches published by Charles J. Freeman.
Journal of Physical Chemistry Letters | 2016
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
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
David J. Heldebrant; Phillip K. Koech; James E. Rainbolt; Feng Zheng; Tricia D. Smurthwaite; Charles J. Freeman; Merit Oss; Ivo Leito
Dalton Transactions | 2015
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
Feng Zheng; David J. Heldebrant; Paul M. Mathias; Phillip K. Koech; Mukund Bhakta; Charles J. Freeman; Mark D. Bearden; Andy Zwoster
Archive | 2015
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
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
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
Greg A. Whyatt; Charles J. Freeman; Andy Zwoster; David J. Heldebrant
Industrial & Engineering Chemistry Research | 2013
Paul M. Mathias; Louis V. Jasperson; David VonNiederhausern; Mark D. Bearden; Phillip K. Koech; Charles J. Freeman; David J. Heldebrant