SOP 005

A. Peroxide Forming Compounds

1. Handling Precautions

a. Peroxides are shock sensitive and have the potential to explode.

b. All peroxide forming chemicals are to be labeled with:

1) Date Received
2) Date Opened
3) Expiration Date

c. Peroxide forming chemicals are to be disposed of within 6 months after the container is opened.

d. All unopened containers are to be disposed of within 12 months of the date received.

e. Peroxide forming chemicals are not to be purchased in quantities that exceed actual needs.

f. Peroxide forming chemicals are not to be used when a precipitate forms or an oily viscous layer appears.

g. Do not attempt to open a container of peroxide forming chemicals when a cap is rusted, stuck or encrusted with scale.

h. Store all peroxide forming chemicals away from light, heat and air.

i. Do not use metal spatulas to handle peroxides because contamination by metals can lead to explosive decomposition. Magnetic stirring bars can unintentionally introduce iron, which can initiate an explosive reaction of peroxides. Ceramic, Teflon, or wooden spatulas and stirring blades may be used if it is known that the material is not shock-sensitive.

j. Avoid friction, grinding, and all forms of impact near peroxides, especially solid peroxides. Glass containers that have screw-cap lids or glass stoppers should not be used. Polyethylene bottles that have screw-cap lids may be used.

k. To minimize the rate of decomposition, store peroxides at the lowest possible temperature consistent with their solubility or freezing point. Do not store liquid peroxides or solutions at or lower than the temperature at which the peroxide freezes or precipitates because peroxides in these forms are extremely sensitive to shock and heat.

2.  Disposal of Peroxide Forming Chemicals

a. Empty Containers

1) Assure no liquid is in the container.
2) Triple rinse the container with water.
3) Dispose of the uncapped container in regular trash.

b. Chemical Waste

1) Fill out a Hazardous Waste Tag.
2) Send the blue copy to Chemical Safety at CI-1001 or FAX to 1-9844.

3.  Inform Chemical Safety, ext. 1-2663, if the peroxide forming chemical is outdated or signs of peroxide are evident.

a. Chemical Safety will schedule a time for pretreatment of the peroxide forming chemical.

4. Pretreatment of peroxide forming chemicals.

a. If it appears a container may be dangerous to open, i.e. crystals around the cap, container bulging, etc., treatment will be done by a disposal company. This will be arranged through Chemical Safety, ext. 1-2663.

5. Before a peroxide forming chemical is picked up for disposal, if there is no potential risk for explosion:

a. Lab personnel must test for peroxides in the following manner:

1) Dip test strips into test solution for 1 second.
2) After 5 seconds, compare color change of strip to the color scale which correlates with the percent of peroxides present.
3) If peroxides are present, refer to Neutralization procedures.

6. Neutralization Procedures for peroxide forming chemicals:

a. Chemical Safety will provide proper training, instruction, support and materials for the neutralization of peroxide forming chemicals.

1) Add Ferrous Sulfate to 1 liter.
2) Stir
3) Test for peroxides using the above test method.
4) Add Hydroquinone reagent to inhibit future formation of peroxides.

NOTE: Contact Chemical Safety, ext. 1-2663, before making any attempt to neutralize a peroxide forming chemical.

6. Collection for Disposal

a. Chemical Safety will collect and transport pretreated peroxide forming chemicals on the first Wednesday following notification for storage and disposal, unless otherwise arranged.

b. Once collected by Chemical Safety, peroxide forming chemicals shall be stored in an explosion-proof refrigerator until relinquished to a professional waste disposal company.

Common Compounds Forming Peroxides During Storage

List A

List B

List C

*3 months
Peroxide Hazard
on Storage

*12 months
Peroxide Hazard
on Storage

**12 months
Hazard due to Peroxide
Initiation of Polymerization

Isopropyl ether Ethyl Ether Styrene
Divinyl Acetylene Tetrahydrofuran Butadiene
Sodium Amide Diazine Tetrafluoroethylene
Potassium Metal Acetal Chlorotrifluoroethylene
  Methyl Butyl Dimethyl Ether Vinyl Acetylene
  Vinyl Ethers Vinyl Acetate
  Dicyclopentadiene Vinyl Chloride
  Diacetylene Vinyl Pyridine
  Cumene Chlorobutadiene

* Represents the maximum time period for storage and retesting for peroxide formation.

** When stored as a liquid, the peroxide-forming potential increases and certain of these monomers (especially butadiene, chloroprene, and tetrafluoroethylene) should then be considered List A compounds.


B. Picric Acid

1. Handling Procedures:

a. When Picric Acid is less than 30% solution in water or it is not hydrated it is to be considered a highly shock sensitive chemical.

b. Containers that have a yellow crystal formation around the cap should not be opened without hydration of the crystals.

1) Hydration Method

a) Use a squeeze bottle filled with water.
b) Rinse the area with crystals, continue to rinse until no yellow liquid is noted.
c) All liquid from rinse procedures must be collected and placed in a suitable container for waste collection.

2. Waste Collection of Picric Acid

a. All Picric Acid containers must be free of exterior crystals

b. If crystals are present they must be hydrated using the above Hydration Method prior to collection for disposal by Chemical Safety.

c. Containers free of exterior crystals will be picked up by Chemical Safety according to prescribed collection procedures for hazardous chemicals (See SOP # 003).