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1、正溴丁烷的制备思考题（Preparationofnbromobutanequestions）Four,n-butylbromide1.Whatisthefunctionofsulfuricacidinthisexperiment?What'swrongwiththeamountofsulfuricacidandtheconcentrationistoolargeortoosmall?Answer:theroleis:reactants,catalysts.Toolarge,thereactiongeneratedalargenumberofHBrout,anditiseasytobro
2、mineionoxidationintobromineelemental;overanhour,thereactionisincomplete.2.Whatimpuritiesmaybefoundintheproductsafterthereaction?Whatisthepurposeofwashingineachstep?Whydoyouneedadrysplitfunnelforwashingwithconcentratedsulfuricacid?Answer:maycontainimpurities:NC4H9OH(NC2H5),2O,HBr,n-C4H9Br,H2OObje
3、ctive:toeachstepwashingwashinginadditiontoHBr,mostofthenC4H9OHofconcentratedsulfuricacid(n-C4H9)from2O,nC4H9OHandtherestofthewaterinmostoftheH2SO4NaHCO3H2SO4andtherestofthewashandfinallywashedexceptNaHSO4andexcessNaHCO3residues.Whenwashingwithconcentratedsulfuricacid,thedryingfunnelshouldbeusedt
4、opreventthereductionoftheconcentrationofsulfuricacidandinfluencethewashingeffect.If1-butylbromidecontainsn-butanol,theformerfractionwillbeformedwhendistillation(1-azeotropicn-butylalcoholis98.6DEGC,13%butanol),whichwillleadtoareductioninrefiningyield.3.Whenwashingproductswithafunnel,theproductis
5、sometimesintheupperlayerandsometimesinthelowerlayer.Whatistheeasywaytojudgeit?Answer:pouralittleoftheupperliquidfromthefunnel,orreleasealittleoftheunderlyingliquidinawatertesttubetoseeifthereisanoilbead.4.Whywashwaterwithsaturatedsodiumbicarbonatesolutionbeforewashing?Answer:firstwashwithwater,c
6、anremovepartofsulfuricacidwithsodiumbicarbonate,preventwash,reactionsodiumbicarbonatewithsulfuricacidtoproducelargeamountsofcarbondioxidegas,thepressurefunnelistoolarge,causingthepistontocomeout,andthenwashthesaturatedsodiumbicarbonatesolutioncanfurtherremovethesulfate.Washingshakeshakeprocesssh
7、ouldpayattentiontodeflation!5.Whenwashingproductswithaseparatingfunnel,whydoyouwanttodeflateimmediatelyaftershaking?Howshoulditbeoperated?Answer:inthisprocess,thegaswillbegeneratedaftershakingsothatthepressureinsidethefunnel
