Radical hydroxylation of aromatic hydrocarbons examined by MINDO/3 methods
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Abstract
MINDO/3 calculations have been made on the potential-energy surfaces for the attachment of OH. radicals to benzene (1) and naphthalene (2) in the vapor state. The activation energies of these reactions are calculated as 88 and 58 kJ/mole. while the enthalpies at 298K are calculated as −211 and −199 kJ/mol. The transition states in (1) and (2) lie closer to the reagents than the products on the reaction coordinate, while (1) has an earlier transition state than does (2). The transition states in these reactions have high dipole moments: 3.1 and 3.6 D, respectively, which are due to charge transfer from the hydrocarbons to the OH.. Quantum-chemical calculations and kinetic data on the reactions of aromatic hydrocarbons with OH. in aqueous solution indicate that the mechanism is probably not one involving electron transfer and a rate-limiting stage in the attachment. These processes are of high performance because the radicals are of high stability, while polar effects determine the selectivity.
Keywords
Enthalpy Benzene Activation Energy Hydrocarbon Transition StatePreview
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- 1.N. A. Vysotskaya, L. G. Shevchuk, S. P. Gavrilova, et al., “Radical hydroxylation for derivatives of benzene and certain aromatic heterocyclics,” Ukr. Khim. Zh., 49, No. 8, 865–867 (1983).Google Scholar
- 2.N. A. Vysotskaya and L.N. Bortun, “The mechanism of radiation-induced homolytic substitution of condensed aromatic hydrocarbons in aqueous solutions,” Radiat. Phys. Chem., 23, No. 6, 731–738 (1984).Google Scholar
- 3.A. K. Pikaev and S. A. Kabakchi, Reactivity in the Primary Radiolysis Products from Water [in Russian], Énergoizdat, Moscow (1982).Google Scholar
- 4.R. C. Binham, M. J. S. Dewar, and D. H. Lo, “Ground states of molecules. 25. MINDO/3. An improved version of the MINDO semiempirical SCF-MO method,” J. Am. Chem. Soc., 97, No. 6, 1285–1293 (1975).Google Scholar
- 5.R. C. Bingham, M. J. S. Dewar, and D. H. Lo, “Ground states of molecules. 26. MINDO/3 calculations of hydrocarbons,” J. Am. Chem. Soc., 97, No. 6, 1294–1301 (1975).Google Scholar
- 6.R. C. Bingham, M. J. S. Dewar, and D. H. Lo, “Ground states of molecules. 27. MINDO/3 calculations for CHON species,” J. Am. Chem. Soc., 97, No. 6, 1302–1306 (1975).Google Scholar
- 7.V. V. Lobanov, “A program for calculating the macroscopic properties of materials in the semiempirical MINDO/3 approximation,” Zh. Strukt. Khim., 26, No. 6, 126–127 (1985).Google Scholar
- 8.J. W. McIver and A. Komornicki, “Structure of transition state in organic reactions. General theory and an application to the cyclobutene-butadiene isomerizations using a semiempirical molecular orbital method,” J. Am. Chem. Soc., 94, No. 8, 2625–2633 (1972).Google Scholar
- 9.R. A. Marcus, “Theoretical relations among rate constants, barriers, and Bronsted slopes of chemical reactions,” J. Phys. Chem., 72, No. 3, 891–899 (1968).Google Scholar
- 10.A. Pross, “The reactivity-selectivity principle and its mechanistic applications,” Adv. Phys. Org. Chem., 14, 69–132 (1977).Google Scholar
- 11.P. V. Gurvich, G. V. Karachevtsev, V. N. Kondrat'ev, et al., Bond Energies, Ionization Potentials, and Electron Affinities [in Russian], Nauka, Moscow (1974).Google Scholar
- 12.L. Eberson, “Electron-transfer reactions in organic chemistry,” Adv. Phys. Org. Chem., 18, 79–185 (1982).Google Scholar
- 13.D. Doboz, Electrochemical Constants [Russian translation], Mir, Moscow (1980).Google Scholar
- 14.R. O. Loutfy and J. H. Sharp, “Correlation between photographic properties of dyes and their electrochemical and spectroscopic parameters,” Photogr. Sci. Eng., 20, No. 4, 165–174 (1976).Google Scholar
- 15.V. Chekulaev and I. Shevchuk, “Reactivities of certain polycyclic aromatic hydrocarbons with OH. radicals,” Izv. Akad. Nauk SSSR, Ser. Khim., 30, No. 2, 138–140 (1981).Google Scholar