Date of Award
Master of Science in Pharmaceutical Chemistry - (M.S.)
Chemistry and Environmental Science
Joseph W. Bozzelli
Tamara M. Gund
Structure, thermochemical properties, bond energies and internal rotation potentials of Acetic Acid Hydrazide (CH3CONHNH2), Acetamide (CH3CONH2) and N-methyl Acetamide (CH3CONHCH3) and their radicals corresponding to loss of hydrogen atom have been studied. Gas phase standard enthalpies of formation and bond energies were calculated using the DFT methods B3LYP/6-31G(d,p), B3LYP/6-31G(2d,2p) and the composite CBS-QB3 methods employing a series of work reactions to further improve accuracy of the ΔHf°(298K). Molecular structures, vibration frequencies and internal rotor potentials were calculated at DFT level. The enthalpies of the parent molecules CH3-C=ONHNH2, CH3-C=ONH2 and CH3-C=ONHCH3 are evaluated as -28.6, -58.1 and -56.5 kcalmol-1 respectively at B3LYP/6-31G(D,P), B3LYP/6-31G(2d,2p) and CBS-QB3 levels. Bond dissociation energies for H--CH2C=ONHNH2, CH3-C=ON(--H)NH2, CH3- C=ONHNH--H, H--CH2C=ONH2, CH3-C=ONH--H, H--CH2-C=ONHCH3, CH3-C=ON(- -H)CH3 and CH3-C=ONHCH2 - H are 99.9, 78.2, 81.9, 100.1, 111.5, 99.9, 104.2 and 93.7 kcal mol-1 respectively. The computed DFT and the Complete Basis Set enthalpy values are in close agreement with each other; and this accord is attributed to use of isodesmic work reactions for the analysis. The agreement also suggests this combination of B3LYP / work reaction approach is acceptable for larger molecules.
Cyclic ethers are a major initial product from the reactions or hydrocarbon radicals with triplet dioxygen (3O2) in low to moderate temperature oxidation and combustion reaction systems and atmospheric chemistry of small hydrocarbons. Thermochemical properties, ΔH°f(298), S°298 and Cp° (T) (10K
Charaya, Sumit, "Thermochemistry and bond energies of acetohydrazide, amides and cyclic alkyl ethers" (2011). Theses. 88.