PERCHLORIC ACID: FORMULA, CHARACTERISTICS AND USES - CHEMISTRY - 2025

The perchloric acid is a strong mineral acid, usually found as a colorless and odorless aqueous solution, corrosive to metals and fabrics. It is a powerful oxidant when hot, but its aqueous solutions (up to about 70% by weight) at room temperature are generally safe, showing only strong acid characteristics and no oxidative properties.

Perchloric acid and its salts (particularly ammonium perchlorate, sodium perchlorate, and potassium perchlorate) find many applications due to their strong oxidizing power.

Launch of the Ares-1 (02 02-2008)

Its production has increased due to its use as a starting material for the production of pure ammonium perchlorate, a basic ingredient in explosives and solid propellants for rockets and missiles.

Perchloric acid 60%

Perchloric acid is also used, on a limited scale, as a reagent for analytical purposes. Its closed container containers can rupture violently under prolonged exposure to heat.

Formulas: Perchloric acid: HClO ₄

CAS: 7601-90-3

2D structure

Perchloric acid

3D structure

Perchloric acid / Ball and rod molecular model

Perchloric acid characteristics

Physical and chemical properties

• Appearance: colorless liquid
• Odor: odorless
• Molecular weight: 100.454 g / mol
• Boiling point: 19 ° C
• Melting point: -112 ° C
• Density: 1.768 g / cm3
• Solubility in water: Miscible
• Acidity (pKa): -15.2 (± 2.0)

Perchloric acid belongs to the group of strong oxidizing acids.

Inflammability

-Strong oxidizing acids are generally not flammable, but they can accelerate the combustion of other materials by providing oxygen (acting as oxidizing agents).

-Perchloric acid solutions can explode due to heat or contamination.

-When heated above 160 ° C, or involved in a fire, they can decompose explosively.

-They may react explosively with hydrocarbons (fuels). It can ignite fuels (wood, paper, oil, clothing, etc.).

-Containers may explode when heated.

-Runoff can create a fire or explosion hazard.

Reactivity

-Strong oxidizing acids are generally soluble in water with the release of hydrogen ions. The resulting solutions have a pH of 1 or close to 1.

-The materials in this group react with chemical bases (for example: amines and inorganic hydroxides) to form salts. These neutralization reactions occur when the base accepts hydrogen ions that the acid donates.

-Neutralizations can generate dangerously large amounts of heat in small spaces.

-Addition of water to acids often generates enough heat in the small region of the mixture to make that part of the water boil explosively, potentially causing very dangerous acid splashes.

-These materials have a significant capacity as oxidizing agents, but that capacity varies from one to the other.

-They can react with active metals (such as iron and aluminum) and also with many less active metals, to dissolve the metal and release hydrogen and / or toxic gases.

-Its reactions with cyanide salts and their compounds release gaseous hydrogen cyanide.

-Flammable and / or toxic gases are also generated by their reactions with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides and weak or strong reducing agents.

-Additional gas-generating reactions occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2) and even carbonates: the carbon dioxide gas of the latter is not toxic but the heat and splashes of the reaction they can be annoying.

-Perchloric acid solutions are strong oxidizing acid solutions.

-They can react vigorously or detonate, when mixed with oxidizable materials (alcohols, amines, borans, dicyanogen, hydrazines, hydrocarbons, hydrogen, nitroalkanes, powdered metals, silanes and thiols, among others).

-Perchloric acid ignites on contact with sulfinyl chloride.

Toxicity

-Strong oxidizing acids are corrosive to fabrics. Acid fumes irritate sensitive tissues (such as the eyes and respiratory system) severely.

-Inhalation, ingestion or contact (of the skin, eyes, etc.) with perchloric acid solutions or its vapors can cause serious injury, burns or death.

-When they come into contact with fire, they can produce irritating, corrosive and / or toxic gases.

-Runoff from fire control or dilution water can cause contamination.

Applications

-Perchloric acid is used in the areas of scientific research and development, and in the manufacture of chemical products and electrical, electronic and optical equipment.

-It is used as a precursor in the production of pure ammonium perchlorate, a basic ingredient in explosives and solid propellants for rockets and missiles.

-Uses for perchloric acid in the home include toilet, metal and drain cleaners, rust removers, in batteries, and as a primer for false nails.

-Industrial uses include: metal refining, plumbing, bleaching, etching, electroplating, photography, disinfection, ammunition, fertilizer manufacturing, metal cleaning, and rust removal.

-Perchloric acid is also used, on a limited scale, as a reagent for analytical purposes.

Clinical effects

Acids cause coagulation necrosis. Hydrogen ions dry out epithelial cells, causing edema, erythema, shedding of tissue, and necrosis, with formation of ulcers and bedsores.

On exposure to these acids via the gastrointestinal route, patients may develop grade II burns (superficial blisters, erosions, and ulcerations) that are at risk of subsequent stricture formation, particularly the gastric route and esophagus.

Deep burns and necrosis of the gastrointestinal mucosa can also develop. Complications often include perforation (esophageal, gastric, rarely duodenal), fistula formation (tracheoesophageal, aortoesophageal), and gastrointestinal bleeding.

Inhalation exposure can cause dyspnea, pleuritic chest pain, cough and bronchospasm, upper respiratory edema, and burns. Upper respiratory edema is common and often life threatening.

Eye exposure can cause severe conjunctival irritation and chemosis, corneal epithelial defects, limbic ischemia, permanent loss of vision and in severe cases of perforation.

Mild dermal exposure can cause irritation and partial thickness burns. Longer or high concentration exposure can cause full thickness burns.

Complications can include cellulitis, sepsis, contractures, osteomyelitis, and systemic toxicity.

Safety and risks

Hazard statements of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS)

The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is an internationally agreed system, created by the United Nations and designed to replace the various classification and labeling standards used in different countries by using consistent criteria globally.

The hazard classes (and their corresponding chapter of the GHS), the classification and labeling standards, and the recommendations for perchloric acid are as follows (European Chemicals Agency, 2017; United Nations, 2015; PubChem, 2017):

GHS Hazard Statements

H271: May cause fire or explosion; Strong oxidant (PubChem, 2017).

H290: May be corrosive to metals (PubChem, 2017).

H302: Harmful if swallowed (PubChem, 2017).

H314: Causes severe skin burns and eye damage (PubChem, 2017).

H318: Causes serious eye damage (PubChem, 2017).

H371: May cause organ damage (PubChem, 2017).

Caution Instruction Codes

P210, P220, P221, P234, P260, P264, P270, P280, P283, P301 + P312, P301 + P330 + P331, P303 + P361 + P353, P304 + P340, P305 + P351 + P338, P306 + P360, P309 + P311, P310, P321, P330, P363, P370 + P378, P371 + P380 + P375, P390, P404, P405, and P501 (PubChem, 2017).

(United Nations, 2015, p. 359).

(United Nations, 2015, p.366).

(United Nations, 2015, p.371).

(United Nations, 2015, p.381).

(United Nations, 2015, p. 394).

References

1. European Chemicals Agency (ECHA). (2016). Perchloric acid. Brief Profile. Retrieved on February 8, 2017, from: echa.europa.eu.
2. JSmol (2017) Perchloric acid. Recovered from: chemapps.stolaf.edu.
3. NASA (2008) Ares-1 launch 02-2008 Recovered from: commons.wikimedia.org.
4. National Center for Biotechnology Information. PubChem Compound Database. (2017). Perchloric Acid - PubChem Structure. Bethesda, MD, EU: National Library of Medicine. Recovered from: pubchem.ncbi.nlm.nih.gov.
5. Oelen, W. (2011) Perchloric acid 60 percent Recovered from: en.wikipedia.org.
6. Wikipedia. (2017). Perchloric acid. Retrieved February 8, 2017, from: es.wikipedia.org.
7. Wikipedia. (2017). Perchloric acid. Retrieved February 8, 2017, from: es.wikipedia.org.