1. Handling Pyrophoric Reagents
Mikhail Alnajjar Ph D
Alnajjar, Ph.D.
e-mail: ms.alnajjar@pnl.gov
Pacific Northwest National Laboratory
(PNNL)
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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Handling Pyrophoric Reagents
Illustrate best practices for handling liquid
p g q
pyrophorics
1) Using a syringe
2) Using a double-tipped needle
17. Handling Pyrophoric Reagents
---Syringe Transfer---
y g
Syringe Transfer Assembly Equipped with an Inert Gas Line
and a Bubbler during Reagent Transfer
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. 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. Handling Pyrophoric Reagents
---Double-Tipped Needle Transfer---
Double-Tipped Needle Assembly Equipped with a Bubbler and
Kept Under an Inert Atmosphere during Reagent Transfer
