Kinetic Studies on the Selective Oxidation of Benzyl Alcohols in Organic Medium under Phase Transfer Catalysis

DOI: https://doi.org/10.9767/bcrec.9.2.6476.142-147
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Submitted: 16-03-2014
Published: 01-08-2014
Section: Original Research Articles
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Kinetic studies on the oxidation of benzyl alcohol and substituted benzyl alcohols in benzene as the reaction medium have been studied by using potassium dichromate under phase transfer catalysis (PTC). The phase transfer catalysts (PT catalysts) used were tetrabutylammonium bromide (TBAB) and tetrabutylphosphonium bromide (TBPB).  Benzyl alcohols were selectively oxidised to corresponding benzaldehydes in good yield (above 90%).  The order of reactivity among the studied benzyl alcohols is p - OCH3 > p - CH3 > - H > p - Cl.  Plots of log k2 versus Hammett's substituent constant (s) has been found to be curve shaped and this suggests that there should be a continuous change in transition state with changes in substituent present in the substrate from electron donating to electron withdrawing. A suitable mechanism has been suggested in which the rate determining step involves both C - H bond cleavage and C - O bond formations in concerted manner. © 2014 BCREC UNDIP. All rights reserved.

Received: 16th March 2014; Revised: 18th May 2014; Accepted: 18th May 2014

[How to Cite: Bijudas, K., Bashpa, P., Nair, T.D.R. (2014). Kinetic Studies on the Selective Oxidation of Benzyl Alcohol and Substituted Benzyl Alcohols in Organic Medium under Phase Transfer Catalysis. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (2): 142-147. (doi:10.9767/bcrec.9.2.6476.142-147)]

[Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.2.6476.142-147]

 

Keywords

Benzyl alcohols; Kinetics; Phase transfer catalysis; Phase transferred monochromate; Selective oxidation.

  1. K. Bijudas 
    Department of Chemistry, N. S. S. College, Manjeri, Malappuram, Kerala - 676122, India

    Assistant Professor

    Dept. of Chemistry

  2. P. Bashpa 
    Department of Chemistry, N. S. S. College, Manjeri, Malappuram, Kerala - 676122, India

    Assistant Professor

    Dept. of Chemistry

  3. T.D. Radhakrishnan Nair 
    Department of Chemistry, N. S. S. College, Manjeri, Malappuram, Kerala - 676122, India

    Retired Professor

    Dept. of Chemistry

    University of Calicut

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