Abstract
In this study, the dissociation constants of the eight amines, namely,
N-(2-aminoethyl)-1,3-propanediamine, 2-methylpentamethylene diamine, N,
n-dimethyldipropylene-triamine, 3,3’-Diamino-n-methyldipropylamine,
Bis[2-(n, n-dimethylamino) ethyl]ether, 2-[2-(Dimethylamino)
ethoxy] Ethanol, 2-(dibutylamino) Ethanol and N-propylethanolamine
were determined from 298.15 K to 313.15 K. Using the van’t Hoff
equation, thermodynamic properties such as the standard state changes of
enthalpy, entropy and Gibbs free energy were calculated. Using
computational chemistry calculations, the amino group protonated first
was predicted. Furthermore, computer free group contribution methods
such as the original Perrin-Dempsey-Serjeant (PDS), the modified PDS and
the Qian-Sun-Sun-Gao (QSSG) model were used to estimate the dissociation
constants of the studied amines. In these methods, the QSSG provided the
most accurate results as the database used in this method was updated
with additional the functional groups as well as information about group
positions. Finally, an artificial neural network was used to predict the
pKa values.