Handling Pyrophoric Reagents

Mikhail Alnajjar Ph DMikhail Alnajjar, Ph.D.

e-mail: ms.alnajjar@pnl.gov

Pacific Northwest National Laboratory(PNNL)(PNNL)

Methods for the Safe Storage, Handling,Methods for the Safe Storage, Handling, and Disposal of Pyrophoric Liquids and

Solids in the Laboratory

Mikhail Alnajjar, Dave Quigley, Fred Simmons, Murty Kuntamukkula David Freshwater & Samuel BiggerKuntamukkula, David Freshwater, & Samuel Bigger

e-mail: ms.alnajjar@pnl.govjj @p g

Journal of Chemical Health & Safety(publication)

Handling Pyrophoric ReagentsHandling Pyrophoric Reagents

Acknowledgement

Jason ArmstrongCindy CaldwellTodd Haynie

Patti Ammonet

Tim Bays, John Linehan, Aaron Appel, Tim Hubler, Michael Bates, Andy Minister, Sam Paulsen, & Judi Johannesen

Neal Langerman

Handling Pyrophoric Reagents

Represent a unique class of reactants They participate in many different types of

reactionsreactions They are very useful in organic synthesis And play an important role in industrial And play an important role in industrial

applications and anionic polymerization

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***temperatures of 130 F (54.4 C) or less

According to U.S. Department of Transportation (DOT):***Pyrophorics as substances (liquid or solid) that, even i ll titi d ith t t l i itiin small quantities and without an external ignition source, can ignite within five minutes after coming in contact with air***

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 ***their safe handling and use ***

Handling Pyrophoric Reagents

Three Types of Pyrophorics

1) Gases (diborane, phosphine, arsine, silane)silane)

These are easiest class of Pyrophorics to handle because the gas can be gconnected directly to the application and use remotely.

Handling Pyrophoric Reagents

Three Types of Pyrophorics

) S 2) 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…) KO (superoxide) forming on the surface of theKO2 (superoxide) forming on the surface of the metal; is shock-sensitive and can explode when handled or cut.

Handling Pyrophoric Reagents

Three Types of Pyrophorics 3) Li id 3) Liquids:

A) Pure liquids (diethylzinc triethylboraneA) Pure liquids (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

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

reagentsreagents Answer any questions you may have Overall goal: to provide guidelines and general

safety precautions to avoid serious or fatal injury.

Handling Pyrophoric ReagentsGeneral PrecautionsGeneral Precautions

Do not work alone (use the Buddy System) Safety glasses, fire-retardant coats & gloves should be Safety glasses, fire retardant coats & gloves should be

mandatory along with chemically-resistant gloves when appropriate

Wear Natural fiber clothing; if possible Synthetic materials Wear Natural fiber clothing; if possible. Synthetic materials 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 and roll may come handy at timesblanket. 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

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 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 confidencematerials 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 Needle ith ga ge 18 or larger is preferredNote: Needle with gauge 18 or larger is preferred.

When possible, use oxygen “FREE” glovebox …

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 firebefore attempting to extinguish the fireNote: 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 causegas/air mixture may be created that, if ignited, may cause far more damage than the original fire.

Avoid the use of Halons as extinguishing agents because h i t i l tl ith h lpyrophoric gases react violently with halogens

Store in gas cabinets with adequate ventilation

Disposal of Pyrophoric Reagents---liquids and Solids---

Syringes, double-tipped needles, spatulas, and reaction assembly, should be rinsed with an inert solventExcess reagents should be diluted with an inert solventExcess reagents should be diluted with an inert solventThe rinsates are transferred to a flask under an inert atmosphere and cooled in a cooling bath (DMK/CO2)St t th t li ti b l l ddi i lStart the neutralization by slowly adding isopropyl alcohol (IPA)Follow the addition of IPA with methanol (a stronger ( gneutralization solvent)Finally, add copious amounts of water or dilute acid if needed to insure that neutralization is completeneeded to insure that neutralization is completeDispose of the waste safely in accordance with requirements or organization’s waste disposal process

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 Pyrophoricsand water/in case of water reactive Pyrophorics.

Gases: Are stored upright in pressurized p g pcylindersSolids: Are stored as suspensions or chunks in

i l il d i t t h f dmineral oil or under an inert atmosphere of dry Nitrogen or ArgonLiquids: Are stored under an inert atmosphereLiquids: Are stored under an inert atmosphere of dry Nitrogen or Argon

Handling Pyrophoric Reagents

Illustrate best practices for handling liquid p g qpyrophorics

1) Using a syringe2) Using a double-tipped needle2) Using a double-tipped needle

Handling Pyrophoric Reagents---Syringe Transfer---y g

Syringe Transfer Assembly Equipped with an Inert Gas Line and a Bubbler during Reagent Transfer

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

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 hazardsNote: Sash has been lowered to reduce potential splash hazards.

Handling Pyrophoric Reagents---Double-Tipped Needle Transfer---

Double-Tipped Needle Assembly Equipped with a Bubbler and Kept Under an Inert Atmosphere during Reagent Transfer

Handling Pyrophoric ReagentsHandling Pyrophoric Reagents

Th kThank you …

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