Safe Handling of Pyrophoric (PP) Reagents · Safe Handling of Pyrophoric (PP) Reagents 1 Purpose...

SafeHandlingofPyrophoric(PP)Reagents

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PurposeThisPowerPointpresenta0onoffersadetaileddescrip0ononthesafehandling,useandstorageofpyrophoricliquids.Theinforma0onprovidedcanassistlabpersonnelwithconduc0ngariskassessment,traininganddevelopinganSOPbeforeusingpyrophoricliquidssuchastert-Butyllithium,diethylzincetc.

Disclaimer:ThisSafetyGuidelinesdocument/SOPwaspreparedexclusivelyfortheuseofUniversityofWisconsin-Madisonstudents,staffandfacultyengagedinacCviCesrelatedtotheireducaCon,research,and/oremployment.ThecontentisintendedtoprovidesafeoperaConalpracCcescurrentlybelievedtorepresentbestpracCcesintheuseandhandlingofchemicalsinvolvedintheprocess,andisnotintendedtoreplacehands-onpracCcaltraininginthetechniquesdescribed.ItremainstheresponsibilityofthePrincipalInvesCgatortoassurethathis/herco-workersareproperlytrainedonhazardmanagement,whichmayincludeadaptaConcontainedwithinthisdocumenttomeetspecificneedstoaddressspecifichazardsinaparCcularexperimentinalaboratory.Referencetoanyspecificcommercialproduct,process,orservicebytradename,trademark,manufacturer,orotherwise,doesnotimplyitsendorsementorrecommendaConbyUniversityofWisconsin-Madison.

Preparedby:TilakChandra,Ph.D.

HazardsA=ributedtothePPReagentManipula?ons

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Pyrophoricreagentsignitespontaneouslywhenexposedtoair,andcancauseseverecaus?cinjuriesorburnsoncontactwithskin,eyesandmucousmembranesastheyreactwithmoistureresul0nginthegenera0onofalkalinehydroxide.Fumesarisingfromthecombus0onofPPcompoundsaremainlylithiumoxideandlithiumhydroxide.Theyalsohaveaburning(caus0c)effect.

EngineeringControls

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Becauseofthedangersofreac0vity(spontaneousigni0on),specialprecau0onsmustbeengagedwhenworkingwithpyrophoricreagents.Allopera0onswithsolidandconcentratedreagentsshouldbeperformedinaproperlyfunc0onalchemicalfumehood.Afireex0nguisher,emergencysafetyshowerandeyewashshouldbereadilyavailablewithin10secondtravel0me.Smallscalepyrophoricmanipula0onscanbecarriedouteasilyinaglovebox,theyprovideexcellentinertatmosphereforpyrophoricchemicals.

Administra?veControlsAvoidworkingalonewhileconduc0ngexperimentwithPPreagents.Thebuddysystemprovidesaddedprotec0onintheeventofanemergency.Knowexactloca0onofeyewashsta0on,safetyshowerandfireex0nguishersbeforestar0ngexperiment.

PersonalProtec?veEquipment

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EyeProtec?onSafetyglassesorgogglesshouldalwaysbeworntoprotecttheeyesfromthecorrosivityofPPcompounds.Addi0onaleyeprotec0on,providedbyafaceshield,isrecommendedinexperimentswherehighervolumesofPPreagentsareemployedandPPsolu0onsarepressurized,forinstanceinordertotransferthemviatubing.BodyProtec?onAlong-sleevedfire-resistantlaboratorycoatwhichisclosedshouldbewornatall0meswhenworkingwithpyrophoricchemicals.Inaddi0on,itisrecommendedtowearfire-resistantclothingunderneath,asopposedtosynthe0cclothingnotintendedtobefireresistantwhileworkingwithpyrophoricchemicals.GlovesNitrileglovesareacceptableformanipula0ngPPreagentsinagenerallaboratoryopera0onbuttheyarecombus0ble.DryandcleanNomex®glovesserveforprotec0onofthehands.

Fig.1

LaboratoryScaleChecklistBeforeWorkingwithPyrophoric(PP)Reagents

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Items Y NSecurelatestversionofSDS/MSDSofPPsolu0onofinterestfromvendor

ReadlatestversionofSDSofPPsolu0onofinterestfromvendor

Aresafetyglasses,gogglesandfaceshieldavailable?

Isaflameresistantlabcoatorcoverallsavailable?

AreglovesofViton®ornitrileavailable?

Areextendedsleeveglovesavailable?

Areleather,closedtoeshoesavailable?

IsanappropriatelysizedboYletotesafetycarrieravailable?

IsaClassBfireex0nguisheravailable?

Knowtheloca0onofnearesteyewashandsafetyshower?

DidyouordertheminimumamountofPPsolu0onnecessaryfortheexperiment?

HasthePPsolu0onboYlebeenstoredat<10oCina0ghtlyclosedcontainer?

Isasuitablelaboratoryfumehoodavailabletoconducttheexperiment?

IsthehoodfreefromcluYer(solventboYles,samples,combus0blematerials)?

Permissionfrom:Org.ProcessRes.Dev.2014,18,1192−1210 Cont.

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Items Y NIsinertgas(drynitrogenorargon)availableinthehood?

Isaninertgasdeliverysystem(Schlenkline)ormanifoldavailableinthehood?

Isaglasswaredryingovenorheatgunavailabletodrytheequipment?

Isaglassdesiccatoravailableofsufficientsizetoallowthedryglasswaretocooltoroomtemperature?

Isavacuumpumpavailable,toevacuatetheequipment,ifthistechniqueisselected?

IsanexplosionproofrefrigeratororcoldroomavailabletostorePPsolu0on?

Haveyoualertedyourlabmates/co-workersthatyouwillbehandlingPPsolu0ons?

Haveyourehearsedyouremergencyresponseprocedure?

Aretheretwoinertgasbubblersavailable?

Isthereasyringeavailablewithasufficientlylongneedle?Or,isthereacannulaavailable?

Hasalltheequipmentbeendriedinanovenat125oCforatleastfourhours?

Wastheequipmentassembledhotandallowedtocooltoroomtemperatureinstreamofinertgas?

Isthereametalbowlunderthereac0onflaskasasecondarycontainment?

Issufficient0meavailabletocompletetheexperiment?

Isaco-workeravailableduringthePPtransfer?

Isthereaninertgaspurgeonduringtheen0reexperiment?

Methods:Small/LargeGlassAssemblyDrying

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Smallflasksandacondenserareeasytodryinanovenandcoolunderacalciumchloridedesiccator,butalargescaleassembly(condenser,1litflaskanddroppingfunnel)cannotbedriedinadesiccator.Aheatgunandvacuumisappropriateforsuchassembly.ASerassemblingtheset-upinafumehood,connecttheassemblytoavacuumusingasuitabletakeoff.ASchlenkline(SL)isappropriateforthisdryingwherenitrogenisusedasaninertgas.HeattheassemblyusingaheatgunandconCnuouslyevacuatetheassembly.DonotheatTygon®tubesusedforchilledwaterfiWed to the condenser and Keck Clips during the dryingprocess.Keck®clipslosetheirholdingcapacityiftheyareheatedunderhightemperatureorusedincorrectly.

(Fig.2)

SafetyMeasures&Techniques

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•  Inthefirststepcleananddryglasswareinanovenabove120oCfor4horusingaheatgunthencoolinaglassdesiccatoroveranhydrouscalciumchloride.•  Inspectyourglasswareandreac0onset-upforanydeepnotchingstarcracks,oranycrackingatallintheflasks,youshouldreplaceitimmediatelyiftheglasswareiscracked.•  Useasecondarycontainmenttosupportthereac0onflaskincaseofanyemergencyorotherpurposessuchashea0ngandcooling.•  DonotcannulatePPreagentsoranypyrophoricchemicalstoanyopenglassware.•  Thehoodsashshouldbeclosedasmuchaspossibleduringthetransferopera0onandreac0on,toprovideanaddi0onallevelofpersonnelprotec0on.

TechniquesforTransferringtert-Butyllithium(fortransferring>10mLDoubleTippedNeedle/CannulaMethod)

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Reac?onassemblyforlarge-scalepyrophoricreagenttransfer

Small-scalepyrophoricreagenttransfer

(Fig.3a)(Fig.3b)

TransferringPyrophoricReagentswithaSyringe

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Transferofpyrophoricreagentsviasyringeisconvenient,butshouldnotbeusedformorethan10mL.Youwillneedasmallposi0vepressureinthereagentboYleinordertodrawthereagentintosyringe.EnsurethatexcesspressureisreleasedthroughthemineraloilbubblerthatisaYachedtothegasline.SLequippedwithapressurereleasesystem,wheretheinertgaslineisventedthroughanoilbubblerisagoodop0on.

Fig.4fillingsyringewithslightN2pressure

I.  ItisrecommendedthatthesyringebeatleasttwicethevolumeofthePPtobedispensed.II.  Thesyringeshouldbedriedinanovenat125°Cforatleast4h,placedinadesiccator(smallglassitems)tocooltoambienttemperature,andthenpurgedwithastreamofinertgas(plas0csyringecanbedriedinadesiccatorwithouthea0ng).

PyrophoricReagentsTransferwithSyringe

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I.  Inserttheneedle,connectedtotheinertgasline(bubbler),throughtheseptumintotheheadspaceabovethereagentmaintainingasmallposi0vepressureinsidetheSure/SealTMpyrophoricreagentboYle.(neverover-pressurizereagentbo@lecontainingPPreagents).

II.  Insertneedleofaluer-locksyringethroughtheseptumintothereagentboYle.

III.  Pulltheplungerbackslowlytofillthesyringewiththerequiredvolumeofreagent.Alwayskeeptheplungerinyourgraspandavoidpullingbacktheplungerquicklyasthisac0oncausesleaksandbuildsgasbubbles.

IV.  OncetherequiredvolumeisaYained,slowlypullupthesyringeneedlefromthepyrophoricreagenttotheoverheadspaceabovetheliquid.

V.  Pulltheplungerupslowlyandallowtheinertgastopushthereagenttrappedintheneedleintothesyringe.

VI.  Shuttheinertgaslineoffandslowlypulltheneedleoutfromtheassemblytocompletethetransfer.

VII.  Rinsesyringeandneedlewithanon-reac0ngsolventajertransferringreagent,andquenchtheresidueunderaninertatmosphereusingisopropanol.

PyrophoricLiquidTransfer:CannulaMethod

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•  SecuretheboYlewithclampthenslightlypressurizetheSure/SealTMboYlewithnitrogenorargon.Insertthedouble-0ppedneedlethroughtheseptumintotheheadspaceabovethereagent.Nitrogenwillpassthroughtheneedle(Fig.5a).

•  Inserttheotherendthroughtheseptumatthegraduateddroppingfunnel(Fig.5b)ofthereac0onapparatuswhichmustbeequippedwithagaslinetoabubblerorcalciumchlorideguardtube.

•  Pre-measurethevolumeyourequireintoanaddi0onfunnel,markitcorrectlythendrytheglasswarethoroughlyasyourset-upunderinertgasoroven.Donotover-pressurizethereagentboYleanduseofSchlenklinenitrogenisrecommended.

Cont.

PyrophoricLiquidTransfer:CannulaMethod

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•  PushtheneedleintotheliquidintheSure/SealreagentboYleandtransferthedesiredvolume(Fig.5c).Tocontroltheflowrate,fitaLuerlockTMsyringevalveconnec0ngtwoelongatedneedles.

•  Thenwithdrawtheneedletoabovetheliquidlevel(headspace,5d).Allownitrogentoflushtheneedleorcannula(Fig.5a&5d).Takeouttheneedlefromthereac0onapparatusfirstandthenfromthereagentboYle(Fig.5e).

Cont.

PyrophoricLiquidTransfer:CannulaMethod

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StorageofPPReagents

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Alwaysstorepyrophoricchemicalsunderaninertatmosphere.ProcuresmallestvolumeofPPreagentforuse.PPreagentswilldegradeover0me.Avoidareaswithheat/flames,oxidizers,andwatersources.BoYleswithpyrophoricmaterialsmustbeclearlylabeledwiththecorrectchemicalname(fullnameandnoacronym)andhazardwarning.Storeincool,dryandwell-ven0latedareaawayfromincompa0blematerials(RTstablePPReagents).“Usealabsafe”Refrigeratorforstoringtemperaturesensi0vePPreagents.NeverallowPPreagentstogetincontactwithmoistureduringstorage.Keepcontainers?ghtlyclosed.Neverreturnexcessreagenttotheoriginalcontainer.

ManagingSpillsInvolvingPPReagents

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Forsmallspillsinsidechemicalfumehood,usedrysand/lime,orothernon-combus0bleMaterialforcoveringthespillmaterial,closethehoodsash.Ifaspilloccursoutsideafumehoodandyouareunabletohandlethespillcallimmediately911.

DisposalofPyrophoricReagents

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Largequan0tyofPPreagentshouldbedisposedofthroughsafetydept.SmallamountsofunusedorunwantedPPmaterialsmustbedestroyedbycarefulquenchingoftheresidue.Transferthematerialstoanappropriatereac0onflaskforHydrolysisorneutraliza0on.Dilutesignificantlywithanunreac0vesolventsuchasheptaneortolueneandplacetheflaskinanicewatercoolingbath.Slowlyaddisopropanoltoquenchpyrophoricmaterials.Uponcomple0on,addmethanolasamorereac0vequenchingagenttoensurecomple0on.Finally,addwaterdrop-wisetomakesuretherearenopocketsofreac0vematerials.AVOIDlowboilingdiluentssuchasetherandpentanethattendtocondensewateruponevapora0on.Donotleavecontainerswithresiduesofpyrophoricmaterialsopentotheatmosphereduetouncontrolledigni0on.Transferneutralizedmixtureintosolventcarboy*fordisposalpurpose.*Beforetransferringquenchedmaterialintosolventcarboy,makesurethereisnoreacCvePPreagentpresent(firehazards).

References

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•  Org.ProcessRes.Dev.18,2014,1192−1210.•  hYps://www.pnl.gov/main/publica0ons/external/technical_reports/PNNL-18668.pdf•  Methodsforthesafestorage;handling;anddisposalofpyrophoricliquidsandsolidsinthelaboratoryJ.Chem.Health&Saf.18(1),2011,5-10.•  Managementof0me-sensi0vechemicals(III):stabiliza0onandTreatmentJ.Chem.HealthSaf.,13(1)2006,24-

29.•  hYp://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Aldrich/Bulle0n/al_techbull_al134.pdf•  hYp://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Aldrich/Bulle0n/al_techbull_al164.pdf•  hYp://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?

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