Kinetic study on the preparation of 4,4′-dinitrostilbene-2,2′-disulfonic acid (II)-kinetic study on the oxidation of p-nitrotoluene-o-sulfonic acid to prepare 4,4′-dinitrobibenzyl-2,2′-disulfonic acid

The aqueous air oxidation of p-nitrotoluene-o-sulfonic acid (NTS) to prepare 4,4′-dinitrostilbene-2,2′-disulfonic acid (DNS) is studied. It is shown that the by-product formation results from either the direct oxidation of NTS or DNS destruction or both under certain conditions. Based on the experimental data, the rate equation of the oxidation of NTS is established, which can be expressed as follows: −d[NTS]/dt = k[NTS][OH]2.8. The kinetic parameters are obtained and interaction between temperature, hydroxide concentration, reaction time and conversion is discussed.