Oxidation of NMST to NMSBA catalyzed by Co/Mn/Br together with porous carbon made from coconut shell with acetic acid as an activator

Abstract In this paper, a heterogeneous catalytic system consisting of Co/Mn/Br/activated carbon is used to catalyze 2-nitro-4-methylsulfonyl benzoic acid (NMSBA) production from the oxidation of 2-nitro-4-methylsulfonyltoluene (NMST) by oxygen. The activated carbon (AC) is made from coconut shell with acetic acid as an activator. The experiments indicate that the best AC is made by immersing coconut shell in 12 mol L−1 HAc solution at 50 °C for 32 h with a liquid/solid ratio (mL/g) of 5:1 and then being heated in nitrogen at 800 °C for 6 h. Compared with the Co/Mn/Br/H3PMo12O40@CAC (CAC, commercial activated carbon originated from coconut shell) catalytic system, the Co/Mn/Br/AC catalytic system is able to gain much higher NMSBA selectivity. In spite of holding smaller surface and less acidic groups, the AC owns much more carboxyl than CAC, which is the main reason for its better performance in the preparation of NMSBA.