Wet oxidation of organic matter employing mixed perchloric and sulphuric acids at controlled temperatures and graded high potentials

Abstract

The oxidation potential of perchloric acid at the boiling point is a function of temperature and concentration. At ordinary temperature no oxidation potential is provided in the concentration range 0 to 73.6%. At its boiling temperature 50% perchloric acid fails to oxidize Fe II except very slowly. At 72.5 % acidity, (the azeotropic concentration), the boiling acid, (203°), is a strong oxidant. For example Cr III is easily oxidized to CrO 3. Between concentrations of 50% to 72.5%, the boiling acid provides oxidation potentials of continuously mounting values. By control of suitable desired concentrations through boiling under reflux, many practical procedures may be devised for the controlled wet oxidations of organic compositions. For higher oxidation potentials, higher concentrations of perchloric acid are required. By the addition of concentrated sulphuric acid in various ratios by volume to 70 % perchloric acid, effective concentrations of the latter may be provided up to and including 100%. Again by control of the particular concentrations of the mixed acids selected, through boiling under reflux, extremely high graded oxidation potentials, under static control, may be provided. The use of sulphuric acid in such applications serves the additional important function of tempering the reaction and controlling reaction rates. The addition of 1 to 2 mg of vanadium as reaction catalyst serves the same purpose. Vanadium also favorably influences the reaction kinetics while shortening the oxidation period required. Procedures making use of these reaction variables are herein experimentally demonstrated. The wet oxidation of such samples as coal, ion-exchange resins, alkaloids, synthetic fabric materials, rubber, heterocyclic ring nitrogen compounds and other materials serve as examples. No hazardous reactions were encountered in this work.