Peroxide Forming Chemicals

This group forms explosive levels of peroxides without concentration; these are the most hazardous and can form explosive peroxide levels even if not opened.

Several methods are available to check for peroxides; the two most common are the use of peroxide test strips or the potassium iodide test. These chemicals shall be tested for peroxide formation or discarded after 3 months of receiving the chemicals.

* Indicates a peroxide former when stored as a liquid monomer.

This group of chemicals will readily form peroxides when they become concentrated (e.g., via evaporation or distillation). The concentration process defeats the action of most auto‐oxidation inhibitors. As a result, these chemicals shall be tested for peroxide formation or disposed of within 12 months of receiving.

This group of chemicals forms peroxides due to initiation of polymerization. When stored in a liquid state, the peroxide forming potential dramatically increases. Liquids shall be tested for peroxide formation or discarded after 6 months, gases after 1 year.

** Can form explosive levels of peroxides if stored as a liquid. When stored as gas, peroxide accumulation may cause autopoly- merization.

Clark, Donald E., Peroxides and Peroxide Forming Compounds, 2000. Texas A&M University. Boston University

• Never work alone with peroxide forming chemicals.
• Due to the strict limitations on prolonged storage of peroxide formers, do not order large containers, only order the amount of peroxide formers you need for planned or foreseeable experiments.
• Always keep a testing record for peroxide forming chemicals including the date received, date opened, and date last tested. Each bottle should be labeled with this information.
• Review the Safety Data Sheets (SDSs) for all chemicals used in the experiment.
• All manipulations of peroxide formers should be conducted in containment devices (e.g. fume hoods, gloveboxes, or similar devices). When working in a fume hood keep the sash as low as possible.
• If there is a high probability of fire or explosion a portable blast shield inside the fume hood is recommended.
• Test for peroxides before any distillation or purification of peroxide forming chemicals. Use extreme caution when concentrating or purifying peroxide forming chemicals as explosions can occur (https://ehs.uci.edu/safety/pdfs/lesson‐learned_peroxide.pdf).
• Never allow peroxide formers to evaporate to dryness, such as during distillation, always leave a minimum of 20% liquid.
• Peroxide crystals formed in a chemical container are particularly likely to accumulate within the threads of the screw cap and may explode when subject to heat, light, friction, or mechanical shock (e.g. unscrewing the cap). Never open, move, or disturb a bottle that is suspected to have peroxides.
• For liquids evidence of possible peroxide formation includes formation of solids or crystals, visible discoloration, and liquid stratification.
• For solids evidence of possible peroxide formation includes formation of a surface crust, and discoloration of the solid.
• Alkali metals and amides should be evaluated based on visual criteria only. There are no peroxide tests that can be used on these materials.
• Never open, disturb, or move a container suspected of having peroxides, immediately notify UK EQMD (859) 323‐ for evaluation or disposal.

NOTE: The use of certain concentrations of perchloric acid must be performed in a fume hood equipped with washdown facilities.

• Segregateperoxide forming chemicals from incompatible materials.
• Store away from ignition and initiation sources such as flames, static electricity, heat, and light.
• Peroxide forming chemicals should be stored in their original manufacturer’s container.
• Minimize the quantity of peroxide forming chemicals stored in the lab.
• If possible, keep the material under an inert atmosphere (e.g. nitrogen, argon) when not in use, except for chemicals that contain an inhibitor that requires oxygen to function.