1978 Volume 36 Issue 12 Pages 1073-1078
The oxidizing action of the new oxidizing system using molten potassium hydroxide-manganese dioxide-air was studied.
In the reaction in nitrogen, the mean oxidation number of the recovered manganese was 2.90, and the yield of terephthalic acid (1) was 33 mol %. The result is explainable by the decrease of the oxidation number of manganese from 4 mostly to 3 and partly to 2.
In the reactions in air and oxygen, the oxidation numbers of the recovered manganese were 3.68 and 3.73, and the yields of (1) were 87 and 76 mol %. In these cases the results are not explainable only by the decrease of the oxidation state of manganese.
Further, it was found that potassium manganate (MnVI) is partly formed in molten KOH-MnO2 in air at the reaction temperature of about 250°C.
From these facts, it has become clear that the manganese in molten KOH-MnO2 in air may function as oxidizing agents with the oxidation number between 6 and 2, and may behave as a catalyst catching oxygen from the atmosphere and giving it to organic compound.
