Naslov
Predicting pKa values of organic pollutants using density functional theory
(Predicting pKa values of organic pollutants using density functional theory)

Autori
Kovač, Dora Katarina ; Pleić, Andrea ; Pulitika, Anamarija ; Kovačić, Marin ; Lončarić Božić, Ana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Skup
Studentski kongres o održivoj kemiji i inženjerstvu (SKOKI)

Mjesto i datum
Zagreb, Hrvatska, 01.04.2023

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
DFT ; pKa ; dissociation

Sažetak
The acid dissociation constant (Ka), as a matter of fact its negative logarithm (pKa) is among the most important physicochemical parameters that affect the characteristics of a molecule. The pKa values are used for determining the strength of acid and is important for predicting the behavior of compounds in aquatic environment. The pKa values can be defined experimentally by potentiometric or spectrophotometric titration of the solution, whereby the pKa value corresponds to the pH value of the solution when 50% of total acid in the solution is dissociated. It is very difficult to experimentally determine pKa values of poorly soluble compounds and compounds with very high or low pKa values. For these reasons, many researchers are focused on the development of computational methods for the precise calculation of pKa values of various compounds. Several methods of density functional theory (DFT) can be used for calculating pKa values [1]. In this work, the most well-known and frequently used method of DFT called B3LYP is used for calculating pKa values of pharmaceuticals diclofenac (DCF), amoxicillin (AMX) and ciprofloxacin (CIP) and of pesticide dicamba (DIC). For conducting the calculation, we used def2svp basis set and PCM solvation model. The pKa values of the compounds were determined using calculated Gibbs free energies of neutral and ionic species in vacuum and solvent by a direct approach and thermodynamic dissociation cycle. The results showed a positive correlation between the calculated pKa values and experimentally determined values from the literature, which indicates the possibility of using the B3LYP method to predict pKa values.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

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