Chemical and physical properties



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Pyrophoric Chemicals Fact Sheet

CHEMICAL AND PHYSICAL PROPERTIES
Pyrophoric chemicals are liquids and solids that have the potential to spontaneously ignite in air at temperatures near 130oF (54oC). They are extremely reactive to oxygen and moisture, so precautions must always be taken to prevent their exposure to air. These chemicals are often sold and stored in flammable solvents, such as ethyl ether, tetrahydrofuran(THF), or pentanes, exacerbating the dangers. Whenever possible, purchase chemicals that are stored in heptane, since it is less hazardous than the other solvents. There are numerous pyrophoric chemicals that are frequently used in scientific research laboratories. Below is a list of some general examples:


  • Grignard reagents, RMgX

  • Metal alkyls and aryls, such as RLi, RNa, R3Al, R2Zn

  • Metal carbonyls such as Ni(CO)4, Fe(CO)5, Co2(CO)8

  • Alkali metals such as Na, K

  • Metal powders, such as Al, Co, Fe, Mg, Mn, Pd, Pt, Ti, Sn, Zn, Zr

  • Metal hydrides such as NaH, LiAlH4

  • Nonmetal hydrides, such as B2H6 and other boranes, PH3, AsH3

  • Nonmetal alkyls, such as R3B, R3P, R3As

    • Phosphorus (white)



HEALTH HAZARDS / TOXICITY
Eyes: Can cause severe burns to the eyes.

Skin: Can cause severe burns to the skin.

Ingestion: May cause severe and permanent damage to the digestive tract. Can cause severe burns to the gastrointestinal tract. May cause central nervous system depression.

Inhalation: Causes chemical burns to the respiratory tract. Exposure produces central nervous system depression. May cause drowsiness, unconsciousness, and central nervous system depression. Vapors may cause dizziness or suffocation.

Chronic: Repeated exposure can cause nervous system abnormalities with muscle weakness and damage, motor incoordination, and sensation disturbances.


EXPOSURE LIMITS
See chemical specific MSDS.
SAFE HANDLING AND STORAGE
Compatibility with other chemicals/materials

Pyrophoric chemicals must be used and stored away from all other flammable and combustible materials such as paper, bench liners, and solvents.


General Storage information

Pyrophoric chemical containers usually come from the manufacturer with secondary containment in metal cans. Keep the manufacturer’s can for storage of the chemicals when not in use, and for disposal of the containers after completion of the experiment. Pyrophoric liquids, or compounds dissolved in a liquid, must be stored in containers that are sealed with PTFE-lined septa to prevent exposures to the air. Minimize stored quantities of pyrophoric chemicals, preferably to the minimum necessary to conduct your experiments. Store these compounds at no more than room temperature and away from heat sources. Whenever possible, store all forms of pyrophorics under inert atmosphere.


Safe Use of Pyrophoric Chemicals
Engineering Controls

  • Laboratories that use pyrophoric chemicals must be equipped with an emergency eyewash station, an emergency shower, and a class C fire extinguisher.

  • Solid pyrophoric compounds must be handled in an inert atmosphere glove box. You can also purchase inexpensive inert atmosphere glove bags if you do not have access to a glove box (http://www.sigmaaldrich.com/labware/products/aldrich-atmosbag.html).

  • Liquid pyrophorics are best handled in an inert atmosphere glove box. If you do not have access to a glove box, work with pyrophoric liquids must be conducted using a cannula or syringe transfer to prevent exposure to air. These procedures must be done in a chemical fume hood. In addition, the work must be conducted using a spill tray with the sash pulled down as low as possible. Needles must have locking mechanisms to prevent accidental disconnection and release of pyrophoric liquids. Mineral oil bubblers must be used at all times in order to release excess pressure from the reaction vessels. A blast shield can make provide an excellent protection barrier, if available.

  • For additional information on the safe handling of pyrophoric liquids, please watch the safety movie from the University of California Las Angeles (UCLA). Keep in mind, some specific details such as what volumes are permissible will depend on what department you work for, and the specific engineering controls you have in place. Please view the video as a general safety tool, and be sure to get more specific information from your supervisor. Link to movie: http://www.youtube.com/watch?v=RaMXwNBAbxc


Administrative Controls

  • Researchers that use pyrophoric chemicals must have Laboratory Safety Training through the Department of Environmental Health and Safety (DEHS) prior to beginning work. (http://www.dehs.umn.edu/training_newlabsafety.htm)

  • Researchers must review standard operating procedures (SOPs) and MSDS prior to beginning work in the laboratory. In addition, procedure-specific training must be given by a qualified, experienced supervisor. DEHS recommends that new researchers practice techniques with non-hazardous chemicals prior to working with the “real thing.” New researchers must be supervised the first few times they conduct any work with pyrophoric chemicals.

  • Pyrophoric chemicals are NOT to be used without at least 2 people present in the laboratory, in case of an accident or emergency. Pyrophoric chemicals must NOT be used outside of normal business hours.

Personal Protective Equipment (PPE)

  • Nitrile gloves, safety goggles, and a protective lab coat must be worn at all times when working with pyrophoric chemicals.

  • Highly flammable synthetic clothing is to be avoided, as well as loose clothing. Always wear long pants and closed-toe shoes. Long hair should be tied back to prevent ignition in the event of a flash fire.

  • Fully enclosed safety goggles or a face shield are preferred, if available, as they offer greater facial protection than safety goggles. Prescription eyeglasses are NOT a sufficient protection barrier for pyrophoric chemicals.


EMERGENCY AND SPILL INFORMATION
Emergency Information:
Eyes: Flush eyes at the emergency eyewash station for 30 minutes. Seek medical attention immediately.

Skin: Remove any contaminated clothing, in case of flash fire. Rinse skin with copious amounts of water for at least 15 minutes. If larger areas of skin are affected, rinse under the emergency safety shower for at least 15 minutes. If you experience any burning or irritation thereafter, seek medical attention.

Ingestion: Do NOT induce vomiting. Seek medical attention immediately.

Inhalation: Remove victim from exposure area to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Do NOT use mouth-to-mouth resuscitation. Seek immediate medical attention or Call 911 if not breathing.

Spill Information:
Large Spills Use extreme caution due to potential for spontaneous ignition. If anyone is exposed or on fire, rinse with copious amounts of water under the emergency shower. Call 911 and evacuate the spill area. Do NOT attempt to clean up the spill yourself. Cordon-off the spill area with tape and keep other people from entering. If possible, provide emergency responders with technical information on the chemicals involved. Contact DEHS immediately at (612) 626-6002.

Small Spills Use extreme caution due to potential for spontaneous ignition. If anyone is exposed, or on fire, rinse with copious amounts of water, or utilize the emergency safety shower. In the event of a flash fire, dial 911. If nobody is injured and nothing has ignited, first access a class C fire extinguisher and place it nearby the spill area prior to proceeding. Then, carefully remove any flammable materials that are near the spill area. Completely cover the spill with powdered lime (calcium oxide, CaO) or dry sand. Next, quench the spill by slowly adding isopropanol to the area. After quenching is completed, double bag spill residues and manifest through the University’s hazardous waste program. Call DEHS at (612) 626-6002 for assistance.

CHEMICAL WASTE AND CLEAN-UP PROCEDURES
Quenching of Pyrophoric Residue Small amounts of unused pyrophorics must be destroyed by

quenching of the residue. The basic procedure for quenching is as follows: Transfer the residue to a reaction flask for neutralization. Dilute with copious amounts of a less hazardous solvent such as heptane or toluene. Place the flask in an ice bath, and slowly add isopropanol to quench pyrophoric residue. Next, slowly add methanol as a more reactive quenching agent to ensure completion. Finally, add water drop-wise to ensure that there are no pockets of reactive materials left. Dispose of as hazardous waste through the University’s Hazardous Waste Program (612) 624-1604. Do not leave containers with residues of pyrophoric materials open to the air, because this is a possible flash fire hazard.


Disposal of Pyrophoric Solids through the Hazardous Waste Program

Larger quantities of pyrophoric solid chemicals can be disposed of as hazardous waste.

Carefully package and label the wastes, according the University’s hazardous waste guidelines (http://www.dehs.umn.edu/hazwaste_chemwaste_umn_cwmgbk_sec2.htm). Contact DEHS at (612) 624-1604 and specifically state that you have pyrophoric hazardous waste that needs removal.
ADDITIONAL INFORMATION


  • For general information regarding the safe use of pyrophoric chemicals, please contact DEHS at (612) 626-6002.

  • If you have any concerns regarding the stability or testing of a chemical, contact the Hazardous Waste Program at (612) 624-1604.


REFERENCES
http://www.ehs.ucsb.edu/units/labsfty/labrsc/factsheets/Organolithium_FS34.pdf
http://pharmacy.osu.edu/safety/pdf/chemhygiene_sop_pyrophoric.pdf
http://ehs.unl.edu/sop/s-pyrophoric_chemicals.pdf
http://ehs.columbia.edu/pyrophorics.pdf
http://www.youtube.com/watch?v=RaMXwNBAbxc
http://www.chemistry.ucla.edu/file-storage/publicview/pdfs/ProceduresSafeSolids.pdf

January, 2010 Page




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