THE THEORETICAL CALCULATIONS AND EXPERIMENTAL MEASUREMENTS OF ACID DISSOCIATION CONSTANT AND THERMODYNAMIC PROPERTIES OF GLYCYL-ASPARTIC ACID IN AQUEOUS SOLUTION AT DIFFERENT TEMPERATURES

koohyar, fardad; Zabihi, Fatemeh; Kiani, Farhoush; Yaghobi, Mojtaba; Shahidi, Sayad Ahmad

dc.creator	koohyar, fardad
dc.creator	Zabihi, Fatemeh
dc.creator	Kiani, Farhoush
dc.creator	Yaghobi, Mojtaba
dc.creator	Shahidi, Sayad Ahmad
dc.date	2020-07-18
dc.date.accessioned	2020-07-29T16:48:45Z
dc.date.available	2020-07-29T16:48:45Z
dc.identifier	http://www.jcchems.com/index.php/JCCHEMS/article/view/1190
dc.identifier.uri	https://revistaschilenas.uchile.cl/handle/2250/147165
dc.description	In this research work, a potentiometric technic was used to measure the acidic dissociate constants (pKa,s) for glycyl aspartic acid (GLY-ASP) at temperatures (298.15, 303.15, 313.15, and 318.15) K and in 0.1 mol/l ionic strength of chloride sodium. Using this data, we calculated the thermodynamic properties (changes of enthalpy, ΔH, changes of entropy, ΔS, and changes of Gibbs free energy, ΔG) for acidic dissociation reaction of GLY-ASP. All analyses of data were studied in pH = 1.5-11 and in the aqueous solution. In addition, the value of the acid dissociation constants (pKa1, pKa2, and pKa3), the optimized structure, and the thermodynamic properties of GLY-ASP were calculated in aqueous solution at various temperatures by ab initio and DFT methods. Density function theory (DFT) has been used based on the B3LYP/6-31+G(d) theory to explain the obtained acid dissociation constants of GLY-ASP as well as interactions between solvent and solvated cation, anion, and neutral species of GLY-ASP. Thomasi’s method was used to analyze the formation of intermolecular hydrogen bonding between the water molecule and various species of GLY-ASP. In addition, the energy gap of anionic, cationic, and neutral species of GLY-ASP were obtained for dissociation reactions of GLY-ASP. Finally, for GLY-ASP, the theoretically calculated and experimentally determined pKa,s were compared together and a good agreement was observed between them in the first, second, and third ionization constant of GLY-ASP.	en-US
dc.format	application/pdf
dc.language	eng
dc.publisher	Sociedad Chilena de Química	en-US
dc.relation	http://www.jcchems.com/index.php/JCCHEMS/article/view/1190/379
dc.rights	Copyright (c) 2020 Journal of the Chilean Chemical Society	en-US
dc.rights	https://creativecommons.org/licenses/by-nc-sa/4.0	en-US
dc.source	Journal of the Chilean Chemical Society; Vol 65 No 2 (2020): Journal of the Chilean Chemical Society; 4759-4768	en-US
dc.source	0717-9707
dc.source	0717-9324
dc.subject	Glycyl aspartic acid	en-US
dc.subject	acid dissociation constant	en-US
dc.subject	thermodynamic properties	en-US
dc.subject	density function theory	en-US
dc.subject	Ab initio.	en-US
dc.title	THE THEORETICAL CALCULATIONS AND EXPERIMENTAL MEASUREMENTS OF ACID DISSOCIATION CONSTANT AND THERMODYNAMIC PROPERTIES OF GLYCYL-ASPARTIC ACID IN AQUEOUS SOLUTION AT DIFFERENT TEMPERATURES	en-US
dc.type	info:eu-repo/semantics/article
dc.type	info:eu-repo/semantics/publishedVersion

This item appears in the following Collection(s)

Journal of the Chilean Chemical Society
[0-9]{4}

Show simple item record