Kinetic studies on permanganate oxidation of acetophenones under phase transfer catalysis

Kinetic studies on the permanganate oxidation of acetopheno_ne and some of its substituents in organic media using th e techn1que of phase transfer catalysis are reported. Tncaprylmethylammonium chloride and tetrabutylammonium bromide have been used as the phase transfer catalysts. The reaction shows first order dependence each o n [ketones] and th e [permanganate io ns] respective ly . The rate coefficients fit well with the Hammett equation and the p-value calculated aorees well with th e reacti on requireme nt s. ' Potassium permanganate is a powerful oxidizing agent both for organic as well as inorganic oxidation reactions. It can be conveniently used as a selective oxidant for removing small quantities of organic matter in water bodies and the reaction assumes special significance when carried out under phase transfer catalytic conditions, as water insoluble organic materials can be oxidized with ease. In the present study acetophenone and its p-nitro, p-bromo, p -chloro, p-methyl, p-methoxy and m-nitro deriva­ ti ves have been subjected to oxidation reactions under phase transfer catalysis. Tricaprylmethylammonium chloride (Aliquat 336) and tetrabutylammonium bromide were used as catalysts in various organic solvents. Traditionally th e organic oxidation reactions in aqueous medium were facilitated by the use of co­ solvents especially the dipolar aprotic ones. This could partially solve the situation through cation solvation. However, with the development of the phase transfer techniques it has become quite easy to carry out oxidation reactions of organic compounds in organic media using permanganate, dichromate, hypochlorite, etc 1 - 3 • Such oxidations have been carried out in heterogeneous system of aqueous and organic media. Reports on the kinetics of oxidation of carbonyl compounds using phase-transferred oxidants are scanty and hence the present work. Experimental