30 June، 2022
PH.D. Dissertation Viva-Chemistry Department
PH.D. Dissertation Viva in the College of Education for Pure Science entitled “Calculation of Ionization Constants for some of Schiff bases derived from vanillin and aniline and its substitutes Experimental and theoretical study “The College of Education for Pure Science, University of Mosul, has done the PH.D. Dissertation Viva entitled ” Calculation of Ionization Constants for some of Schiff bases derived from vanillin and aniline and its substitutes Experimental and theoretical study “,On Thursday, June 30, 2022, the College staff including the respected Dean of the College, Assistant Professor Dr. Qais Ismail Ibrahim, the Honorable Scientific Associate and Administrative Associate, the Honorable Head of the Department of Chemistry, and a number of the college’s teachers were attended the viva. This study, presented by the PH.D. Student Rawaa Daoud Sulaiman Al-Uezbaky in the Department of Chemistry, involves the preparation of nine imine compounds derived from vanillin, aniline and its substitutes at the site of Ortho, Meta, and Para with groups of nitro, methyl and chlorine.The verification of structural form of prepared Schiff bases have been studied by using physical methods like melting point , Infrared spectroscopy IR , Electronic spectroscopy U.V and Nuclear magnetic resonance spectroscopy NMR . The main point of this study is to determine the ionization constants pKa1 and pKa2 of the prepared compounds by the spectrometric titration method, which is characterized by its accuracy.It has been observed that1- The variance in the values of the ionization constants pKa1 of the prepared Schiff bases is in line with the effect of the electron-withdrawing and electron- donating substituents groups.2- The values of the ionization constants pKa2 of the prepared Schiff bases were not affected by the presence of the substituted aggregates.3- The values of the ionization constants pKa1 and pKa2 are affected by temperature, and through the thermodynamic variables of the ionization reaction were extracted, which proved that the ionization process is not spontaneous (+ΔG) and endothermic (+ΔH) and varies between increasing regularity (-ΔS) and increasing irregularity (+ΔS).Schiff’s bases were also theoretically studied using two methods of quantum mechanics, which are the ab-initio calculations HF method and the semi-empirical method AM1, from which some physical constants were calculated, such as Mulliken charge and the energy values of orbitals HOMO and LUMO . then , these orbitals values have been used in the calculation of some function which have the relation with molecular stability like hardness , electronic chemical potential and electrophilicity index . The theoretically calculated constants were linked with the practical values of the ionization constants through simple and multiple regression analysis. The results show a weak relationships in the values of the correlation coefficient R2. the best relationships that were obtained between Millikan’s charge on C3 and C6 atoms, the total energy and the pKa1 values calculated by AM1 method to give the correlation coefficient R2 of 0.852.The Viva committee was chaired by Prof. Dr. Emad Abdulilah Saleh / University of Mosul /College of Education for Pure Science and the membership of Prof. Dr. Ahmed Najm Abd / University of Diyala / College of Science, Asst. Prof. Dr. Suhad Shakir Muhammad / University of Baghdad / College of Education Ibn Al Haitham, Asst. Prof. Dr. Huda Abdul Razzaq Younes / Northern Technical University / Technical Institute-Mosul, Asst. Prof. Dr. Feda Hasan Marie / University of Mosul /College of Education for Pure Science and under the supervision and membership of Asst. Prof. Dr. Zaheda Ahmed Najim / University of Mosul / College of Education for Pure Science.
