Revision 10/2018

The requirements in Penn's Chemical Hygiene Plan SOP: Corrosives  and SOP:  Strong Oxidizers apply to all work involving perchloric acid.  The Fact Sheet below gives hazard information and precautions for working with this chemical; however, this information is provided as a supplement to the SOPs, which must first be read and understood by anyone planning to work with this chemical.

Background

Perchloric acid is a colorless, odorless, oily liquid that is extremely corrosive and a powerful oxidizing agent.  An explosion or fire may result when concentrated perchloric (72%) comes in contact with organic or combustible materials.  Heating perchloric acid at any concentration leads to potent oxidizing conditions and therefore explosion risk.  When possible, substitute perchloric acid with a less hazardous material. 

Approvals

EHRS approval is required for any perchloric acid purchases that exceed concentrations of 40%.

Storage

  • Store perchloric acid in its original glass bottle and inspect the bottle monthly.
  • Date the bottle once it is opened and clearly mark the concentration on the bottle.
  • Immediately dispose of a solution of perchloric acid if any discoloration is visible, as this indicates that the acid has begun decomposition and the products are known to be spontaneously explosive. 
  • Inspect the bottle for the accumulation of a white solid, particularly around the neck joint.  The solid is the perchloric acid salt which is shock sensitive and highly reactive. 
  • Store perchloric acid in a secondary container and segregated from other organic reagents. 
  • Store the acid only in a corrosives-storage cabinet; do not store concentrations equal to or greater than 40% perchloric acid in wood cabinets.   

Work Practices

Do not heat perchloric acid of any concentration.  

If a protocol requires the heating of a perchloric acid solution, contact EHRS.

Explosive perchlorate salts can form in exhaust ducts when perchloric acid is heated. For this reason, specialized fume hoods with a neutralizing washdown function are required for all processes in which perchloric acid is exposed to heat.   No fume hoods of this type are available on Penn's campus, and thus, the practice of heating perchloric acid is not permitted. 

The heat from exothermic reactions must also be controlled to avoid elevating the temperature of any process involving perchloric acid of greater than 40% concentration.

Even at room temperature and low concentrations (less than 40%), perchloric acid will cause severe burns on contact with skin, eyes or mucous membranes.  At a minimum, a cotton lab coat, safety glasses and nitrile gloves must be worn for working with perchloric acid at any concentration. A chemical apron is recommended for work with concentrations greater than 72%. 

Never use perchloric acid while alone and notify others when in use.

Spills

In the event of a small spill, neutralize with 10% sodium carbonate; do not use organic materials, such as paper towels or Kim-Wipes to clean up spills. For large spills, evacuate the area and contact EHRS immediately; as the acid begins to dry, it concentrates and therefore increases the hazard. 

Waste

Perchloric acid stocks should be inspected monthly and prolonged storage should be avoided due to the build-up of shock sensitive perchloric salts.  Do NOT mix waste with organic waste!  Contact EHRS for waste pick-up. For more details see the Fact Sheet: Gas-Producing Waste.  

Emergencies

Emergency Contacts

General emergency response information can be found at Emergency Info

Spills

General procedures for chemicals spill response can be found in Section X: Chemical Spills in this CHP.

Do not hesitate to call EHRS for assistance with spill cleanup for perchloric acid.

24 hours: 215-898-4453

Contact Penn Police (511) only if the spill involves a fire, imminent risk of fire, an injury requiring an ambulance, or if there is a hazard that may affect others in the building.