Influence of Cationic Micelle on the Oxidation of Acetaldehyde by N-Bromophthalimide

Abstract

The kinetics of oxidation of acetaldehyde by N-bromophthalimide (NBP) has been studied in the presence of cationic surfactant, cetyltrimethylammonium bromide (CTAB) at 308 K. The order of the reaction with respect to substrate (acetaldehyde) and oxidant (NBP) is first and positive fractional with respect to the [H⁺]. The rate of the reaction decreased with increase in dielectric constant of the medium. The rate constant first increased with increasing concentration of CTAB and after attaining peak, this rate constant decreased with increase in CTAB concentrations, on further increasing the concentration, it became almost constant. Addition of the inorganic salts, that is, [Cl⁻] and [Br⁻] rate of the reaction increased. CH₃COOH was identified as the main oxidation product of the reaction. Activation parameters have been calculated. The rate constant and binding constant with the surfactant have also been evaluated.

Keywords:

• Acetaldehyde
• binding constant
• micellar oxidation
• n-bromophthalimide
• rate constant

Acknowledgments

Y. R. Katre thanks the University Grants Commission Regional Office Bhopal for the research project grant.

Notes

Reaction conditions: [CH₃CHO] = 0.01 mol/L, Hg(OAc)₂ = 2 × 10⁻⁴ mol/L, [H⁺] = 0.01 mol/L, [CTAB] = 3.6 × 10⁻⁴ mol/L, CH₃COOH = 50%, temp. 308 K.

Reaction conditions: [NBP] = 1 × 10⁻⁴ mol/L, Hg(OAc)₂ = 2 × 10⁻⁴ mol/L, [H⁺] = 0.01 mol/L, [CTAB] = 3.6 × 10⁻⁴ mol/L, CH₃COOH = 50%, temp. 308 K.

Reaction conditions: [NBP] = 1 × 10⁻⁴ mol/L, Hg(OAc)₂ = 2 × 10⁻⁴ mol/L, [CH₃CHO] = 0.01 mol/L, [CTAB] = 3.6 × 10⁻⁴ mol/L, CH₃COOH = 50%, temp. 308 K.

Reaction conditions:[NBP] = 1 × 10⁻⁴ mol/L, Hg(OAc)₂ = 2 × 10⁻⁴ mol/L, [CH₃CHO] = 0.01 mol/L, [CTAB] = 3.6 × 10⁻⁴ mol/L, [H⁺] = 0.01 mol/L, temp. 308 K.

Reaction conditions: [NBP] = 1 × 10⁻⁴ mol/L, Hg(OAc)₂ = 2 × 10⁻⁴ mol/L, [CH₃CHO] = 0.01 mol/L, [H⁺] = 0.01 mol/L, CH₃COOH = 50%, temp. 308 K.

Reaction conditions: [NBP] = 1 × 10⁻⁴ mol/L, Hg(OAc)₂ = 2 × 10⁻⁴ mol/L, [CH₃CHO] = 0.01 mol/L, [H⁺] = 0.01 mol/L, CH₃COOH = 50%, [CTAB] = 3.6 × 10⁻⁴ mol/L.