Kinetics and mechanism of the oxidation of substituted benzyl alcohols by pyrazinium dichromate

DEĞİRMENBAŞI N., BOZ N.

ASIAN JOURNAL OF CHEMISTRY, cilt.20, sa.5, ss.3866-3874, 2008 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 20 Sayı: 5
  • Basım Tarihi: 2008
  • Dergi Adı: ASIAN JOURNAL OF CHEMISTRY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.3866-3874
  • Anahtar Kelimeler: kinetics, mechanism, oxidation, substituted benzyl alcohols, pyrazinium dichromate, QUINOXALINIUM DICHROMATE, EFFICIENT REAGENT, ORGANIC-COMPOUNDS, FLUOROCHROMATE, CHLOROCHROMATE, BROMOCHROMATE, CHROMIUM(VI), BROMINATION
  • Ankara Hacı Bayram Veli Üniversitesi Adresli: Hayır

Özet

Pyrazinium dichromate oxidizes benzyl alcohol and substituted benzyl alcohols to the corresponding aldehydes in dimethyl sulfoxide and in the presence of acid. The rate of the reaction is dependent on the concentrations of the substrate, pyrazinium dichromate and acid. The oxidation of alpha,alpha-dideuteriobenzyl alcohol exhibits a substantial primary kinetic isotope effect (k(H)/k(D)) = 6.61 at 303 K). Polymerization of acrylonitrile is not induced in this reaction. From the kinetic data, the activation parameters have been calculated. The analysis of the dependence of the kinetic isotope effect on temperature indicated that the reaction involves a symmetrical cyclic chromate ester in the rate-determining step. A suitable mechanism has been proposed.