Handling Pyrophoric Reagents


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Handling Pyrophoric Reagents

  1. 1. Handling Pyrophoric Reagents Mikhail Alnajjar Ph D Alnajjar, Ph.D. e-mail: ms.alnajjar@pnl.gov Pacific Northwest National Laboratory (PNNL)
  2. 2. Methods for the Safe Storage, Handling, and Disposal of Pyrophoric Liquids and Solids in the Laboratory Mikhail Alnajjar, Dave Quigley, Fred Simmons, Murty Kuntamukkula, Kuntamukkula David Freshwater & Samuel Bigger Freshwater, e-mail: ms.alnajjar@pnl.gov jj @p g Journal of Chemical Health & Safety (publication)
  3. 3. Handling Pyrophoric Reagents Acknowledgement Jason Armstrong Cindy Caldwell Todd Haynie Patti Ammonet Tim Bays, John Linehan, Aaron Appel, Tim Hubler, Michael Bates, Andy Minister, Sam Paulsen, & Judi Johannesen Neal Langerman
  4. 4. Handling Pyrophoric Reagents  Represent a unique class of reactants  They participate in many different types of reactions  They are very useful in organic synthesis  And play an important role in industrial applications and anionic polymerization
  5. 5. Handling Pyrophoric Reagents Definition  According to Occupational Safety and Health Administration (OSHA) and National Fire Protection ( ) Association (NFPA): ***Pyrophorics as substances that will self-ignite in air at temperatures of 130°F (54.4 C) or less*** 130 F (54.4°C) less  According to U.S. Department of Transportation (DOT): ***Pyrophorics as substances (liquid or solid) that, even in i small quantities and without an external i iti ll titi d ith t t l ignition source, can ignite within five minutes after coming in contact with air***
  6. 6. Handling Pyrophoric Reagents Due to their Inherent Nature,  Pyrophorics (gases, solids, and Liquids) “Ignite Spontaneously upon exposure to air” Therefore, *** Special precautions must be taken to ensure their safe handling and use ***
  7. 7. Handling Pyrophoric Reagents Three Types of Pyrophorics  1) Gases (diborane, phosphine, arsine, silane) These are easiest class of Pyrophorics to handle because the gas can be g connected directly to the application and use remotely.
  8. 8. Handling Pyrophoric Reagents Three Types of Pyrophorics  2) S ) Solids: A) Finely divided metals (Fe, Mg, U) B) Alkali metals (Li, Na, K, Na-K Alloy) C) Metal hydrides (LiAlH4, KH, UH3) D) Others (Ni-carbonyl, Raney Ni, FeS, FeS2, K2S, etc…) KO2 (superoxide) forming on the surface of the metal; is shock-sensitive and can explode when handled or cut.
  9. 9. Handling Pyrophoric Reagents Three Types of Pyrophorics  3) Li id : Liquids A) Pure liquids (diethylzinc, triethylborane (diethylzinc triethylborane, tributylphosphine, hydrazine – hypergolic and used in rocket fuel; an explosives) B) Solutions (alkyl metals such as Methyllithium, n-Butyllithium, t-Butyllithium) The alkyl metals are usually dissolved in pentane, hexane, diethyl ether, or THF
  10. 10. Handling Pyrophoric Reagents Objectives  Provide general precautions for handling pyrophorics  A brief discussion on proper techniques for disposal  A brief discussion on proper techniques for storage  Illustrate best practices for handling this class of reagents  Answer any questions you may have  Overall goal: to provide guidelines and general safety precautions to avoid serious or fatal injury.
  11. 11. Handling Pyrophoric Reagents General Precautions  Do not work alone (use the Buddy System)  Safety glasses, fire retardant coats & gloves should be fire-retardant mandatory along with chemically-resistant gloves when appropriate  Wear Natural fiber clothing; if possible Synthetic materials possible. tend to melt instead of charring when exposed to high heat.  In case of emergency, use the safety shower or a fire blanket. Stop, drop, blanket Stop drop and roll may come handy at times  Read the manufacturer’s MSDS and understand the technical information within … or find experienced staff  Work must be performed inside a (clean) Fume Hood with the sash down for protection from chemical splashes
  12. 12. Handling Pyrophoric Reagents General Precautions  The bottle should be secured to a stand with a clamp before use to prevent from tipping over  Ensure that the assembly is purged and maintained under an inert atmosphere  Practice the experimental technique with non-hazardous materials to refine the technique and build confidence  When extracting liquid pyrophoric from a reagent bottle, use a Luer-lock airtight glass syringe with a wide bore. Note: Note Needle with ga ge 18 or larger is preferred ith gauge preferred.  When possible, use oxygen “FREE” glovebox …
  13. 13. Handling of Pyrophoric Reagents ---Gases--- Gases Minimally-sized cylinders should be used when dealing with pyrophoric gases and stored in upright position Remote manual shutdown devices should be used … as it is the best procedure to stop the flow of the gas before attempting to extinguish the fire Note: extinguishing the fire while the flow of gas is continuing is extremely dangerous; an explosive cloud of gas/air mixture may be created that, if ignited, may cause that ignited far more damage than the original fire. Avoid the use of Halons as extinguishing agents because pyrophoric gases react violently with h l h i t i l tl ith halogens Store in gas cabinets with adequate ventilation
  14. 14. Disposal of Pyrophoric Reagents ---liquids and Solids--- Syringes, double-tipped needles, spatulas, and reaction assembly, should be rinsed with an inert solvent Excess reagents should be diluted with an inert solvent The rinsates are transferred to a flask under an inert atmosphere and cooled in a cooling bath (DMK/CO2) Start the St t th neutralization b slowly adding i t li ti by l l ddi isopropyl l alcohol (IPA) Follow the addition of IPA with methanol (a stronger ( g neutralization solvent) Finally, add copious amounts of water or dilute acid if needed to insure that neutralization is complete Dispose of the waste safely in accordance with requirements or organization’s waste disposal process
  15. 15. Storage of Pyrophoric Reagents Typically: keep away from heat and ignition sources, flammable and combustible materials, oxidizers, air, and water/in case of water reactive Pyrophorics Pyrophorics. Gases: Are stored upright in p p g pressurized cylinders Solids: Are stored as suspensions or chunks in mineral oil or under an i t atmosphere of d i l il d inert t h f dry Nitrogen or Argon Liquids: Are stored under an inert atmosphere of dry Nitrogen or Argon
  16. 16. Handling Pyrophoric Reagents  Illustrate best practices for handling liquid p g q pyrophorics 1) Using a syringe 2) Using a double-tipped needle
  17. 17. Handling Pyrophoric Reagents ---Syringe Transfer--- y g Syringe Transfer Assembly Equipped with an Inert Gas Line and a Bubbler during Reagent Transfer
  18. 18. Handling Pyrophoric Reagents ---Syringe Transfer--- y g Syringe Transfer Assembly with Inert Gas Line (1), Bubbler (2), Secure Reagent Bottle (3), and Fire Resistant Gloves
  19. 19. Handling Pyrophoric Reagents ---Syringe Transfer--- y g Transfer Assembly in Fume Hood (1) Fire resistant pilot glove (2) Fire resistant lab coat (3) safety glasses with side shield. Note: Sash has been lowered to reduce potential splash hazards hazards.
  20. 20. Handling Pyrophoric Reagents ---Double-Tipped Needle Transfer--- Double-Tipped Needle Assembly Equipped with a Bubbler and Kept Under an Inert Atmosphere during Reagent Transfer
  21. 21. Handling Pyrophoric Reagents Thank Th k you … Questions??? Comments!!!