Common Peroxide Forming Compounds:
List A
Peroxide Hazard on
Storage
Isopropyl ether
Divinyl acetylene
Potassium metal
Sodium amide
Potassium amide
Vinylidene chlorine
List B
Peroxide Hazard on
Concentration
Ethyl ether
Tetrahydrofuran
Dioxane
Acetal
Methyl isobutyl ketone
Ethylene glycol dimethyl ether
Vinyl ethers
Dicyclopentadiene
Diacetylene
Methyl acetylene
Cumene
Tetrahydronaphthalene
Cyclohexene
Methylcyclopentane
t-Butyl alcohol
List C
Hazard Due to Peroxide
Initiation of Polymerization
Styrene
Butadiene
Tetrafluoroethylene
Chlorotrifluoroethylene
Vinyl acetate
Vinyl chloride
Vinyl pyridine
Chlorobutadiene (Chloroprene)
9,10-Dihydroanthracene
Indene
Dibenzocyclopentadiene
Peroxide
Hazards
This pamphlet is intended as a reminder of
the hazards of peroxide formation in
chemicals with which you may potentially
work. Please review the information and
check your chemicals on a regular basis. If
you have any questions or observe signs of
peroxide formation contact the Office of
Environmental Health and Safety (OEHS) at
the numbers listed below.
•List A compounds may form peroxides simply during storage. These compounds must be
properly consumed or properly discarded after exposure to air. Peroxide accumulations can
result in explosion even without being concentrated. Store unopened containers no longer than
three months dispose of open containers within three days.
•List B compounds will form peroxides in storage readily through the process of concentration.
This process will defeat the action of most peroxidation inhibitors. Special management and
accountability, is required particularly with HPLC grade compounds. HPLC grade inhibitors are
packaged without auto-oxidation inhibitors typically because of the interference potential with
the UV detection of eluted species. Test six months after opening and dispose within twelve
months of date received.
•List C compounds can present a hazard due to peroxide initiation of polymerization. When
stored in the liquid state, the peroxide forming potential dramatically increases. Test six
months after opening and dispose within twelve months of date received.
Environmental Health & Safety
Charles River Campus: 353-4094
Medical Campus: 638-8830
Web: http://www.bu.edu/EHS
Peroxide Formation
Visual Identifiers
Hazard Analysis of Test Results:
Highly explosive peroxide compounds can
form as a variety of chemicals are exposed to
air over a period of time. This problem is
most prevalent in ethers, but can also occur in
a selection of other organic compounds and
to some alkali metals and amides. A number
of severe laboratory explosions have
occurred across the nation due to handling
old peroxide forming compounds. As a result,
extreme caution must be used to prevent the
formation of peroxides in these chemicals.
Organic solvents contained in glass bottles
provide the investigator with the ability to visually
inspect the container and its contents. As bottles
containing organic solvents are typically amber
or brown glass, a soft light source, like a
flashlight, is effective in lighting the interior of the
bottle to allow the inspector a good view of
liquid. The light source should either be used as
a back light or a side light to the bottle to avoid
distortion. This should be performed without
picking up or moving the container. The
investigator is searching for:
·3-30 ppm: Expired compounds testing
within this range offer little or no threat of
violent reaction on the given test date. For
compounds testing in this range, remove
from laboratory.
Most peroxide formers are purchased from
the manufacturer with an inhibitor like
hydroquinone, tert-butyl catechol or BHT,
which function to prevent the formation of
peroxides by consuming free radicals in the
solvent as they are formed. The inhibitor can
be burned off by several factors, leading to
the development of peroxides. This had led to
several laboratory accidents around the
world.
The development of peroxides is usually due
to one of the following factors:
·Oxygen is a necessary ingredient for
peroxide formation. A cap left off a container
or drum, or a loose fitting seal may supply
enough oxygen to initiate peroxide formation
by eliminating the inhibitor and supporting the
initiation of the auto-oxidation process.
·Light sources, including sunlight, promote
the auto-oxidation process and the
eradication of the inhibitor. Light, though, will
only promote the auto-oxidation process if
there is sufficient oxygen present in the
container. Once formed, however, peroxides
can undergo autodetonation in direct sunlight
with destructive results.
·Storage time gives peroxides time to develop
and form structures. Since auto-oxidation is a
self sustaining reaction, the peroxide
formation process increases along with an
increase in the hazards.
·Gross contamination – Hard crystal formation in
the form of chips, ice-like structures, crystals,
solid mass or an obscure cloudy media.
·Contamination – Clear liquid presenting wisplike structures floating in suspension.
If any visual contamination is visible, do not
open or move the container and contact EHS
at 3-7233 (3-SAFE) on the Charles River
Campus or 4-6666 on the Medical Campus
immediately.
Testing for Peroxides
There are several methods of testing for
peroxides, two of which are most commonly
used:
·Peroxide Test Strips
Peroxide Test Strips, available from safety and
scientific supply companies, provide semiquantitative results and are simple to use. The
strip is saturated with a representative sample of
the liquid phase of the chemical. A section of the
strip will change color if peroxides are present,
and the color will then be compared to a graph,
indicating the concentration of peroxides up to
100 ppm.
·Potassium iodide (KI) test
Simple Chemistry can also be used to dissolve
100 mg of potassium iodide in 1 ml of glacial
acetic acid, ad to 1 ml of suspect solvent. A pale
yellow color indicates a low concentration of
peroxides and a bright yellow or brown color
indicates a higher concentration. This is the
preferred method of testing diisopropyl ether.
·30-80 ppm: Expired or mismanaged
compounds originally inhibited by the
supplier may pose a threat to the operation
of the laboratory. There have been
documented exothermic reactions during the
reduction of peroxides in containers with this
range of peroxides. It is recommended that
the investigator contact OEHS and have the
container picked up for disposal.
·Greater than 80 ppm: The container is
considered potentially shock sensitive. It
should not be moved, and OEHS should be
contacted immediately to remove the
container.
Container Labeling
For the safety of everyone involved,
containers of peroxide forming chemicals
should be marked with the date the container
was first received, first opened, the results of
any peroxide tests.
Remember to:
·Always store peroxide forming chemicals in
the original container they came in
·Read the MSDS carefully before use
·Never store peroxide forming chemicals
near heat, sunlight or ignition sources
·Adhere to the testing schedule according to
the chemicals designated listing
·Test for the presence of peroxides before
distilling or performing other processes which
may concentrate peroxides.
·Dispose of all expired chemicals