A Method for the Preparation of Perchloric Acid

Abstract

Perchloric Acid is a substance resembling sulfuric acid in many respects. It is a strong acid, very stable in solution, and has a high boiling point. It possesses some advantages over sulfuric acid, such as being monobasic, and having relatively few insoluble salts. (K, Rb, Cs, and Tl perchlorates are only slightly soluble.) Hence a cheap way of making perchloric acid would be highly advantageous to the chemical industry. The present methods of its production are rather expensive, employing the electrolytic production of sodium perchlorate and the distillation of the latter with sulfuric acid under reduced pressure. The product, a 60% perchloric acid is now sold for $7 to $8 per pound. Ammonium perchlorate is obtainable at a fairly low cost, (about 2O [cents] per pound) and might be used as a basis for the cheaper preparation of perchloric acid. Obviously the most direct method of accomplishing this would be the replacement of the NH4 radical in NH4ClO4 by H. It is proposed in this paper to find whether the ammonium ion in ammonium perchlorate solution can be oxidized by means of the oxides of nitrogen, producing only perchloric acid solution and gaseous products. The ideal reaction would be: (I) 2NH4ClO4 + N2O3 = 2N2 + 2HClO4 + 3H2O. This leaves no reaction products from which the perchloric acid need be purified, and hence it is desired to approach in practice this equation as closely as possible.