A model for prediction of product distributions for the reactions of phenol derivatives with hydroxyl radicals

Kilic M., Koctuerk G., San N., CINAR Z.

CHEMOSPHERE, cilt.69, sa.9, ss.1396-1408, 2007 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 69 Sayı: 9
  • Basım Tarihi: 2007
  • Doi Numarası: 10.1016/j.chemosphere.2007.05.002
  • Dergi Adı: CHEMOSPHERE
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1396-1408
  • Anahtar Kelimeler: photodegradation, hydroxyl radicals, phenol derivatives, photocatalytic degradation, DFT calculations, COSMO, GAS-PHASE REACTION, REACTION-RATE CONSTANTS, PHOTOCATALYTIC DEGRADATION, PULSE-RADIOLYSIS, OH RADICALS, ORGANIC-COMPOUNDS, TIO2 SUSPENSIONS, PHOTODEGRADATION, 4-NITROPHENOL, EXCITATION
  • Yıldız Teknik Üniversitesi Adresli: Evet

Özet

In this study, with the intention of estimating the photocatalytic or photodegradation rates and finding certain predictors to be used for the determination of the most probable reaction path and the primary intermediate, the reactions of (OH)-O-center dot radicals with 11 phenol derivatives including benzene were modeled. For 43 possible reaction routes, calculations of the geometric parameters, the electronic and thermodynamic properties of the reactants, the product radicals and the transition state complexes were performed with the semiempirical PM3 and DFT/B3LYP/6-31 G* methods. The solvation effects were computed using COSMO as the solvation model. Based on the results of quantum mechanical calculations, the rate constants, the branching ratios and the product distributions of all the possible reaction paths were calculated by means of the transition state theory. Three predictors were determined for the prediction of the most probable transition state and the reaction path. The differences in the reaction rates were explained in terms of the presence of hydrogen bonds in the transition state complexes and the entropy effects. Finally the results obtained were compared with the available experimental data in order to assess the reliability of the proposed model. (C) 2007 Elsevier Ltd. All rights reserved.