Overview of Perchloric acid
 Perchloric acid is the inorganic compound with the formula HClO4. Usually encountered as an aqueous solution, this colourless compound is a strong acid comparable in strength to sulfuric and nitric acids. It is useful for preparing perchlorate salts, especially ammonium perchlorate, an important rocket fuel. Perchloric acid is also dangerously corrosive and readily forms explosive mixtures.
Perchloric acid is produced industrially by two routes. The tradition method exploits the very high aqueous solubility of sodium perchlorate (209 g/100 mL of water at room temperature). Treatment of such solutions with hydrochloric acid gives perchloric acid, precipitating solid sodium chloride:
NaClO4 + HCl → NaCl + HClO4
The concentrated acid can be purified by distillation. The alternative route, which is more direct and involves no salts, entails anodic oxidation of aqueous chlorine at a platinum electrode.
Specifications of Perchloric acid of HHH Technology
| Appearance |
White or light-yellow crystal |
White or light-yellow crystal |
White or light-yellow crystal |
| Perchloric acid(dry state),% ≥ |
99.5 |
99.0 |
98.0 |
| Moisture,% ≤ |
0.30 |
0.50 |
0.80 |
| Water insoluble matter,% ≤ |
0.01 |
0.03 |
0.03 |
| Chloride(Cl),% ≤ |
0.15 |
0.20 |
0.30 |
| Sulphate(SO4),% ≤ |
0.01 |
0.02 |
0.02 |
| Chromate(CrO4),% ≤ |
0.01 |
0.02 |
0.02 |
| Iron(Fe),% ≤ |
0.005 |
0.03 |
0.05 |
Usage of Perchloric acid
Perchloric acid is mainly produced as a precursor to ammonium perchlorate, which is used as rocket fuel. The growth in rocketry has led to increased production of perchloric acid. Several million kilograms are produced annually.Perchloric acid, a superacid, is one of the strongest Brønsted-Lowry acids. Its pKa is −10. It provides strong acidity without interference from potential nucleophiles such as sulfate or chloride that complicate the use of sulfuric and hydrochloric acids. Other acids of noncoordinating anions, such as fluoroboric acid and hexafluorophosphoric acid are susceptible to hydrolysis, whereas perchloric acid is not. Despite hazards associated with the explosiveness of its salts, the acid is often preferred in certain syntheses. For similar reasons, it is a useful eluent in ion-exchange chromatography.
Synthesis of Perchloric acid
Perchloric acid is produced industrially by two routes. The tradition method exploits the very high aqueous solubility of sodium perchlorate (209 g/100 mL of water at room temperature). Treatment of such solutions with hydrochloric acid gives perchloric acid, precipitating solid sodium chloride:
NaClO4 + HCl → NaCl + HClO4
The concentrated acid can be purified by distillation. The alternative route, which is more direct and involves no salts, entails anodic oxidation of aqueous chlorine at a platinum electrode.
Anhydrous perchloric acid is an oily liquid at room temperature. It forms at least five hydrates, several of which have been characterized crystallographically. These solids consist of the perchlorate anion linked via hydrogen bonds to H2O and H3O+ centers Perchloric acid forms an azeotrope with water, consisting of about 72.5% perchloric acid. This form of the acid is stable indefinitely and is commercially available. Such solutions are hygroscopic.
Storage of Perchloric acid
Packing in 25kgs bags or 1000 kgs bags
Storage: Isolate from incompatible substances. Containers of this material may be hazardous when empty since they retain product residues (vapors, liquid); observe all warnings and precautions listed for the product.
Attention:Hermetically enclosed, place in ventilated places, protect form solarization, keep away form oil, acid and other reducing substances during storage and transportation.
Anhydrous and monohydrated perchloric acid are explosive, but the usual aqueous solutions are stable in the absence of organic compounds. It is very corrosive to skin and eyes. Upon contact with concentrated perchloric acid, organic materials such as cloth and wood ignite. Salts of perchloric acid are also powerful oxidizers that can be explosive. Perchlorate salts tend to be more stable than their chlorate counterparts, which has led to their increased use in pyrotechnic compositions due to safety concerns.
Because of these hazards, perchloric acid is usually handled under fume hoods with wash-down and air scrubbing capabilities, which are not available on standard laboratory fume hoods. The crystalline form of the acid, which is explosive and shock sensitive, can precipitate on hood surfaces; washing down the hood interior solves this problem.
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