Peroxidizable Compounds 

All laboratory workers must learn to recognize and safely handle peroxidizable compounds. Formation of peroxides is accelerated by light and heat. Some organic and inorganic compounds are capable of reacting with atmospheric oxygen to form potentially explosive peroxides. This reaction of molecular oxygen and peroxidizable compounds is formed by a process called autoxidation or peroxidation.   

Substances which have undergone peroxidation are sensitive to thermal or mechanical shock and may explode violently. Peroxide forming substances include: aldehydes, ethers (especially cyclic ether), compounds containing benzylic hydrogen atoms, compounds containing the allylic structure (including most alkenes), vinyl, and vinylidene compounds. The tables listed below further detail classes of chemicals that may form explosive peroxides. 

 Safe Handling and Usage 

Labels on peroxide forming substances must include the date the container was received, date first opened, date expired, and the initials of the person who first opened the container. Including a notice such as “Warning-Peroxide Former” on the container can also be helpful. When interacting with peroxides, do not use a metal spatula because it could lead to explosive decomposition.  If the concentration of peroxides is found to be 20ppm or greater, it is considered explosive and Northeastern University’s hazardous waste vendor will NOT dispose of it. Please contact OARS immediately for any peroxide former substances found to be 20 ppm or greater. 

Follow these 9 management guidelines to ensure that peroxide forming chemicals remain safe to use:  

1. Ensure all peroxide forming chemicals are up to date in ChemTracker, SciShield’s chemical inventory system 
   1. a. While adding peroxide forming chemicals to ChemTracker, you must indicate both the received and expiration dates for containers to ensure timely disposal and testing frequency. 

2. Keep chemical containers tightly closed. Tightly sealing containers and stabilizing them with an added chemical or packing under inert gas such as nitrogen or helium will reduce the chance of peroxides forming. 
3.  Keep chemicals in opaque containers away from light sources. Exposure to light accelerates peroxide formation. Airtight amber glass containers are best. 
4. Label all peroxide forming chemicals with the peroxide former label (pictured below). 
5. Monitor the container volume for evaporative loss.  
6. Test for peroxides quarterly, preferably before each use. Assume peroxide forming chemicals contain peroxides unless they have been recently tested. Place the test data on the container for the next user.   
7. Properly dispose of chemicals that are within their maximum retention times.  
8. Purchase chemicals in the smallest amount necessary. 
9. If refrigeration is required, make sure it is appropriately designed for the storage of flammable substances. 

Hazardous Waste Disposal 

Depending on the peroxide concentration of the chemical, there would be different ways to manage and dispose of them.  For instance, if more than 1 year has passed since a peroxide-forming substance from class I or II (see table below) was opened, it should be disposed of as hazardous waste.  Dispose of class III (see table below) peroxidizable solvents within one year of purchase or 6 months of opening.  Please follow the steps in order to have your peroxidizable waste picked up: 

1.  Use a peroxide test strip to test for the concentration of peroxides if the peroxide forming substance is within its maximum retention time.
2.  If concentration is less than 20ppm:
   • Fill in the correct information and the date of the test on the hazardous waste disposal label (got to Hazardous Waste Page for updated label).  
   • Tape the test strip below the hazardous waste disposal label, so our waste vendor will be able to know the compound has a peroxide concentration of less than 20ppm 
   • Submit a pickup request within the same week of the test. 
3.  If it is more than 2 years old and has not been tested or if crystals, precipitation, or an oily viscous layer forms: If concentration is more than 20ppm: 

• • Do not open the container to test it 
  • Contact OARS for assistance.  

Evaluation and Testing 

The following test procedures may be used on most organic solvents. However, there is not one simple test procedure for detection of peroxides in substances such as alkali metals, alkali metal alkoxides, amides, or organometallics.  

1. Before testing, examine the chemical for visible crystals, precipitate or an oily viscous layer.   
2. Do not test or treat any peroxide forming chemicals if you are unsure of the age, there are visible crystals, precipitate or an oily viscous layer.  Contact the Office of Academic and Research Safety (OARS) for next steps if the above occurs.  DO NOT handle the chemical further because crystals subject to movement or friction may cause an explosion. 
3. Determine whether it is safe to test for peroxides. If the contents of the container have evaporated to less than 10% of the original volume, do not test for peroxides. 
4. Test for peroxides using Peroxide Test Strips. Peroxide test strips can be requested through OARS using the hazardous waste pickup request form in SciShield  Note: If you wish to only receive supplies, you can simply indicate that on the pickup request page.   
5. Destruction of peroxides. If you see crystals or viscous liquid in the container or are not comfortable testing your chemical, it must be deactivated by personnel arranged by OARS. Secure the area near the chemical so that no one will disturb it. Contact OARS; we will contact you to arrange for deactivation. Note: deactivation occurs at the expense of the laboratory. Protect the substance from any unnecessary movement and secure the area where it is being stored.