On March 12, 2020, Noroozi, Javad; Smith, William R. published an article.Application In Synthesis of 2,2′-(tert-Butylazanediyl)diethanol The title of the article was Prediction of Alkanolamine pKa Values by Combined Molecular Dynamics Free Energy Simulations and ab Initio Calculations. And the article contained the following:
Knowledge of aqueous protonation constants (pKa) of chem. species is of significant importance in CO2 reactive absorption system design. Their theor. prediction has mainly relied on implicit solvent models, and the performance of explicit solvent simulations based on classical force fields have rarely been studied. In this paper, we report the results of simulations in explicit TIP3P water with the General Amber Force Field (GAFF) and with the SMD continuum solvent method for the deprotonation pKa values of 29 conformationally diverse alkanolamine species commonly used in CO2 capture. In both cases, we employ the Tissandier value for the hydration free energy of the proton (“The proton’s absolute aqueous enthalpy and Gibbs free energy of solvation from cluster-ion solvation data”, Tissandier, M.D. et al., J. Phys. Chem. A, 1998, 102, 7787-7794). The ideal-gas reaction free energies and their uncertainties were obtained from electronic structure calculations using five different compound methods (CBS-QB3, CBS-APNO, G3, G3B3, G4). The hydration free energies of the neutral and protonated forms of the alkanolamines were calculated using the semiempirical AM1-BCC charge method, in addition to several partial at. charge sets based on the RESP fitting method using electrostatic potentials computed at different ab initio theory/levels in the gas phase as well as in the presence of the solvent reaction field. We incorporated the Galvani surface potential of the ions in the (pKa) calculations Although the individual species hydration free energies show significant sensitivity to the charge model, the resulting pKa values from different charge models are quite similar. Moreover, we found that the protonated amine hydration free energies show slightly less sensitivity to the partial charge method than in the case of the neutral amine. While the predicted pKa values based on the RESP charges yield reasonable agreement with the exptl. data, they are prone to occasional disagreement for mols. of complex geometry. The best performance was achieved using the semiempirical AM1-BCC charges, which showed a mean absolute error of less than 0.73 pKa units in comparison with exptl. data. Our results suggest that the AM1-BCC charge method may be used to model electrolyte solutions encountered in the CO2 reactive absorption process. The experimental process involved the reaction of 2,2′-(tert-Butylazanediyl)diethanol(cas: 2160-93-2).Application In Synthesis of 2,2′-(tert-Butylazanediyl)diethanol
The Article related to alkanolamine deprotonation protonation carbon dioxide capture aimd simulation, Physical Organic Chemistry: Theoretical Organic Chemical Concepts, Including Quantum and Molecular Mechanical Studies and other aspects.Application In Synthesis of 2,2′-(tert-Butylazanediyl)diethanol
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