A comparative study of two stage electrochemical oxidation of Toluene, P-Ethoxy toluene, O-Chlorotoluene and P-Isopropyl toluene using Ce4+/Ce3+... medium

Two stage electrochemical oxidation of toluene, p-ethoxy toluene, o-chloro toluene and p-isopropyl toluene to their corresponding aldehydes were carried out using Ce4+/Ce3+ redox mediator in methane sulphonic acid medium. Ceric methane sulphonate was prepared as homogeneous solution as well as yellow crystalline solid in 2 M methane sulphonic acid under optimized conditions. The order of ease of chemical oxidation of these compounds is as follows: p-Ethoxy toluene > Toluene > p-isopropyl toluene > o-chloro toluene. The duration of chemical oxidation depends on the reaction temperature and the concentration of methane sulphonic acid. Higher concentration of methane sulphonic acid decreases the duration of oxidation. The yield of p-ethoxy benzaldehyde, benzaldehyde, o-chloro benzaldehyde and p-methyl acetophenone is 95%, 93%, 70% and 37% respectively. P-Isopropyl toluene interestingly gave p-methyl acetophenone as the major product and hence the yield of corresponding aldehyde was low