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1、OrganicSyntheses,Coll.Vol.4,p.261(1963);Vol.34,p.26(1954).DI-tert-BUTYLMALONATE[Malonicacid,di-t-butylester][I.ISOBUTYLENEMETHOD]SubmittedbyAllenL.McCloskey,GuntherS.Fonken,RudolphW.Kluiber,andWilliamS.Johnson1.CheckedbyJamesCason,GerhardJ.Fonken,andWilliamG.Dauben.1.ProcedureA500-ml.P
2、yrexheavy-wallednarrow-mouthedpressurebottleischargedwith100ml.ofether(Note1),5ml.ofconcentratedsulfuricacid,50.0g.(0.48mole)ofmalonicacid,andapproximately120ml.(about1.5moles)ofisobutylene(Note2),whichisliquefiedbypassageintoalargetesttubeimmersedinaDryIce-acetonebath.Thebottleisclose
3、dwitharubberstopperwhichisclampedorwiredsecurelyinplace(Note3)andisshakenmechanicallyatroomtemperatureuntilthesuspendedmalonicaciddissolves(Note4).Thebottleischilledinanice-saltbathandopened;thenthecontentsarepouredintoaseparatoryfunnelcontaining250ml.ofwater,70g.ofsodiumhydroxide,and2
4、50g.ofice.Themixtureisshaken(carefullyatfirst),thelayersareseparated,andtheaqueousportionisextractedwithtwo75-ml.portionsofether.Theorganiclayersarecombined,driedoveranhydrouspotassiumcarbonate,andfilteredintoadroppingfunnelattachedtotheneckofa125-ml.modifiedClaisenflask(Note5).Theflas
5、kisimmersedinanoilbathatabout100°,andtheexcessisobutyleneandetherareremovedbyflashdistillationeffectedbyallowingthesolutiontoruninslowlyfromthedroppingfunnel.Thedroppingfunnelisthenremoved,andtheresidueisdistilledatreducedpressure.Thefractionboilingat112–115°/31mm.iscollected.Theyieldo
6、fcolorlessdi-tert-butylmalonateis60.0–62.0g.(58–60%),nD251.4158–1.4161,freezingpoint?5.9to?6.1°(Note6)and(Note7).2.Notes1.Increaseintheconcentrationsofreactantsandproductbyeliminationofthesolventshiftstheequilibriumtotherightandthusincreasestheyieldofester.Inseveralrunsbythecheckersinw
7、hichthedescribedprocedurewasfollowedexceptthatetherwasomitted,isobutylenewasincreasedto240ml.(3moles),andshakingwascontinuedfor12–15hourstoeffectsolution,yieldsof88–91%wereobtained.Whenetherwasusedassolvent,thelargeramountofisobutyleneraisedtheyieldtoonly73%.Thesubmitters,however,hav
