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Determination of p K a for substituted benzoic acids in mixed solvent using density functional theory and QSPR
Author(s) -
Senior Samir A.,
Nassar Ahmed M.
Publication year - 2011
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.23048
Subject(s) - chemistry , benzoic acid , quantum chemical , quantitative structure–activity relationship , density functional theory , solvent , computational chemistry , quantum chemistry , charge density , correlation coefficient , molecule , thermodynamics , stereochemistry , organic chemistry , mathematics , quantum mechanics , physics , supramolecular chemistry , statistics
The p K a of some substituted benzoic acid were calculated using three different methods in 50% ethanol/water at 273.15 K with B3LYP/6‐31G(d,p) level of calculations. The calculated p K as were compared with the experimental values. The quantitative structure property relationship was found to give good results compared with the first principle methods. The solution‐phase quantum chemical descriptors were found to give more accurate p K as than the gas‐phase descriptors. The participation of quantum chemical descriptors as bond lengths and charge density mainly affects the acidity constant of studied compounds as represented by high correlation coefficient factors for the obtained equations. The obtained equations were applied to predict the acidity constant of some related structures to benzoic acid. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011