Perchloric Acid is a clear, odorless liquid that is stable at room temperature. It is highly volatile and requires special precautions when in use, handled, or in the working vicinity. At 150ᵒ C and above, or at a concentration greater than 72%, perchloric acid is a strong oxidizer and eventually becomes unstable. At concentrations below 72%, perchloric acid is a highly corrosive. Substitution of perchloric acid with a less hazardous chemical or a dilute solution of less than 48%, if applicable, is recommended. Use of an amount 48% or greater requires close supervision or a knowledgeable, skilled person to perform the work. This document serves as guidance to all users of perchloric acid ensuring proper and safe use within laboratories
Hazards
- At a highly corrosive concentration, perchloric acid may cause severe burns to the eyes, skin, and mucous membranes upon contact.
- Many hazards involve potential explosions and/ or fire.
- When heated, vapors produced can condense within fume hood ventilation ductwork potentially causing dangerous formation of explosive perchlorates.
- Contact with organic materials such as cotton, wood, paper, etc. may cause an explosion or fire once the perchloric acid dries.
- Note that clothing is also made of organic material.
- Perchloric acid must not be distilled in a vacuum as this may form an unstable anhydride causing a spontaneous explosion.
- Many chemicals will produce reactions with perchloric acid including:
- Acetic anhydride
- Alcohol
- Reducing agents
- Metals such as sodium, calcium, and lithium
- Incompatible greases
Protection
- Principle investigators must ensure that all personnel working with or around perchloric acid are properly trained and knowledgeable regarding hazards and safety procedures.
- Must be familiar with the chemical safety data sheet (SDS). This can be found online (see references section also).
- Personal Protective Equipment includes:
- Eye protection: Splash-proof safety goggles
- Gloves: Polyvinyl chloride (PVC) or neoprene
- Face shield: Worn with safety goggles
- Lab coat
- Ventilation: Fume hood must be designated for use of perchloric acid.
- Metal-free
- Shatter-proof glass
- Procedures using a concentration of 50% or less, without heating, may be used in a standard fume hood.
- Procedures using a concentration greater than 50% with heating must be used in a perchloric acid fume hood with a wash down feature.
- Always lower the fume hood sash when working.
- Laboratory personnel must be familiar with the location and operation of safety features.
- Eyewash/drench hose
- Safety Shower
- Perchloric acid quantity within the laboratory should be limited to a one-pound reagent bottle.
- Should remain in the original glass container and in a glass/ceramic secondary containment tray in case of spills.
- The reagent bottle should be rinsed with water after use and returned to secondary containment tray.
- Should be separated from other chemicals, but it can be stored with other corrosive inorganic acids in a corrosive-resistant cabinet.
- Perchloric acid is incompatible with the following:
- Organic chemicals
- Flammable or combustible materials
- Dehydrating agents such as sulfuric acid
- Use non-reactive plastic or preferably glass when working.
- NEVER use metal.
- Use only glass-to-glass apparatuses and silicon-based lubricants for joints.
- Do not use rubber stoppers, tubes, or stopcocks.
- All glass apparatuses should be rinsed with water after perchloric acid work.
- Do not allow perchloric acid to freeze or dry.
- Dispensing and transfer methods:
- Use a dispensing burette or a reaction flask to measure out the quantity of perchloric acid needed.
- Always transfer the perchloric acid over secondary containment to catch any spills that may occur.
- In the event of a spill, the following steps should occur:
- Immediately dilute the spill with large quantities of water.
- Spread sodium bicarbonate to isolate the spill. Be careful when utilizing bases to neutralize strong acids. The heat produced can inadvertently cause formation of vapors.
- Mop and rinse with water repeatedly if the spill occurs on a wooden surface.
- A second neutralization with sodium bicarbonate is recommended.
- Do NOT use organic materials to clean up the spill such as paper towels, cotton rags, and kim wipes.
- Organic materials may spontaneously ignite upon contact.
- If organic materials are inadvertently used, wet the material with water and place into a sealed plastic bag.
- When heating perchloric acid:
- This should only be performed in a perchloric acid hood, not a standard fume hood.
- Hot plates, electric mantles, steam baths, or steam-heated sand baths are acceptable means of heating.
- Gas flames or oil baths should NOT be used.
- When disposing of perchloric acid:
- NEVER mix the unwanted waste with other chemical waste.
- Perchloric acid waste should have a designated waste container properly labeled with hazardous waste labels provided on the UA EHS website.
- Do not accumulate large quantities of waste.
- Contact EHS for a chemical waste pick up (see references section).
Emergency Procedures for Exposure
- Immediately provide first aid based on the chemical SDS instructions.
- Seek medical attention as soon as possible.
- A copy of the SDS should be taken with the exposed person for quick treatment.
References
Hazardous Waste Labels – Environmental Health and Safety
Waste Disposal Request – Environmental Health and Safety
Training
EHS requires in-person training for use, handling, and storage of perchloric acid in laboratories on UA campus.
For further questions, contact the EHS Laboratory Safety Team.