Phase transfer catalyzed reaction of n-Octanol
Advancing the chemical engineering fundamentals
Catalysis (T2-13P)
Keywords: Phase transfer, Catalysis, Kinetics, Enhancement factor
Phase Transfer Catalyzed reaction of n-Octanol
T.Sankarshana*, J.S.N.Murthy
University College of Technology, Osmania University, Hyderabad, India.
Kinetics of oxidation reaction of n-octanol by potassium permanganate was investigated using the phase transfer catalyst (PTC), tricaprylyl methyl ammonium chloride (Aliquat 336) under both homogeneous and heterogeneous conditions. The rate constants obtained are compared under these conditions.
Experiments were conducted in a batch reactor to determine the homogeneous kinetics. Purple benzene containing tricaprylyl methyl ammonium permanganate was prepared by contacting aqueous potassium permanganate solution with benzene consisting of the phase transfer catalyst, tricaprylyl methyl ammonium chloride. Benzene layer (purple benzene) was separated and used for reactions by adding n-octanol at different conditions.
A 0.06 m diameter borosilicate agitated reactor with baffles was used to find the kinetics under heterogeneous conditions. Experiments were performed by dispersing benzene containing n-octanol and PTC in aqueous potassium permanganate solution.
The results indicated that the oxidation of n-octanol by permanganate was first order with respect to each of the reactants resulting in an overall second order rate expression. The second order rate constant determined under both homogeneous and heterogeneous conditions agreed well.
Different phase transfer catalysts like, tricaprylyl methyl ammonium chloride (Aliquat 336), triethyl benzyl ammonium chloride (TEBAC), tetra butyl ammonium bromide (TBAB), tetra butyl ammonium iodide (TBAI) were compared for their effectiveness. Aliquat 336 was proved to be more effective and gave the highest enhancement factor of 7. The activities of these catalysts were found to be consistent with the findings in literature.
Runs were made to find the extractability of quaternary ammonium permanganate ion at different speeds of agitation and for different volume ratios of organic and aqueous phases. The results show that the concentration of permanganate ion in organic phase reaches its saturation value with in three minutes for the stirrer speeds above 450 rpm and is equal to the initial concentration of catalyst.
Presented Wednesday 19, 13:30 to 15:00, in session Catalysis (T2-13P).
