專業(yè)英語(yǔ)實(shí)驗(yàn)報(bào)告

Preparationofbenzylalcoholandbenzoicacid湛江師范學(xué)院11化本2班專業(yè)英語(yǔ)實(shí)驗(yàn)報(bào)告First,thepurposeoftheexperiment

1.Learningtheprinciplesandmethodsofpreparationofbenzylalcoholandbenzaldehydebenzoicacid.

2.Morefamiliarwiththeuseofamechanicalstirrer.

3.Furtherunderstandtheextraction,washing,distillation,dryingandrecrystallizationbasicoperations.

4.Comprehensivereviewandconsolidatebasicskillsinorganicchemistryexperiment.Second,thebasicprinciple

Noα-Haldehydeoccursintheconcentratedalkalinesolutiononthedisproportionationreaction,thealdehydeisoxidizedtoacarboxylicacidmoleculeandanothermoleculealdehydeswerereducedtothealcohol,thereactioncalledCannizzaroreaction.ThisexperimentCannizzaroreactionofbenzaldehydeoccursinconcentratedsodiumhydroxidesolution,benzylalcoholandbenzoicacidwasprepared,followingreactionformula:Third,themainreagentandinstrument

1.Reagentsbenzaldehyde10mL(0.10mol),sodiumhydroxide8g(0.2mol),concentratedhydrochloricacid,diethylether,asaturatedsodiumhydrogensulfitesolution,10%sodiumcarbonatesolution,driedoveranhydrousmagnesiumsulfate.

2.Instrument100mLroundbottomflask,sphericalcondenser,aseparatoryfunnel,straightcondenser,distillationhead,thermowell,thermometer(250℃),escortsmanifoldpipe,theconicalflask,thehollowplug,graduatedcylinders,beakers,Brinellfunnel,suctionflask,dishsurface,infraredlight,mechanicalstirrer.Fourth,theexperimentalprocedure

1.Mechanicalstirrerandarefluxcondenserinstalledin250mLthree-neckedflask,andtheotherportpluggedinFigure1.

2.8gofsodiumhydroxideand30mLofwaterwasaddedandstirredtodissolve.Coolish,10mLoffreshlydistilledbenzaldehyde.

3.Opentheblender,adjustthespeed,sostirsmoothly.Heatedtorefluxforabout40min.

4.Heatingwasstopped,wasslowlyaddedfromthesphericalcondensercoldcatchy20mL,shakeevenlycooledtoroomtemperature.

5.Afterthereactionwascooledtoroomtemperature,pouredintoaseparatoryfunnel,andextractedthreetimeswithdiethylether,each10mL.Theaqueouslayerreservedforfutureuse.

6.Threeetherextractswerecombined,successivelywashedwith5mLofsaturatedsodiumbisulfite,washedwith10mL10%sodiumcarbonatesolution,washedwith10mLofwater.

7.Etherlayerwasseparated,driedintoaconicalflask,addanhydrousmagnesiumsulfate,payattentiontotheflaskstoppered.

8.Figure2isinstalledinalow-boilingliquiddistillationapparatusandslowlyheatedtodistilloutdiethylether(recovery).

9.Distillationatelevatedtemperatures,whentheairtemperatureisraisedto140℃switchcondenser,collectingfractionsof198℃~204℃,isbenzylalcohol,theamountofvolumerecoveryyieldiscalculated.

10.Step5Theaqueouslayerwasslowlyaddedtothereserved30mLcontaining30mLofconcentratedhydrochloricacidandthemixtureofwater,whilestirringwithaglassrod,awhitesolidprecipitated.

11.Cooling,filtration,togivethecrudeacid.

12.Thecrudeacidwasrecrystallizedusingwaterasasolvent,theneedtoaddactivecarbon.Aftertheproductwasdriedunderaninfraredlampload,recoveredyieldwascalculated.V.Notes

1.Theexperimentneedswithether,andtheetherethereasytousefire,mustnothaveanykindofopenflameinthevicinityofthetime.SteamedethercanbeconnectedwithinalongrubbertubeintubeescortspassintothebranchpipeunderthesinkpipesorleadoutsidetoacceptUsedcoldbathtocool.

2.Purifiedwaterasthecrystallizationsolventcanbere-benzoicacid,benzoicacidsolubilityinwater:80℃,each100mLofwatersolubleacid2.2g.SixQuestions

1.ComparetheCannizzaroreactionaldolreactionwithaldehydestructureonthedifferences.

2.Inthisexperimentthetwoproductsisbasedontheprincipleoftheseparationandpurificationofwhat?Itwaswashedwithsaturatedsodiumhydrogensulfiteand10%sodiumcarbonatesolutionwiththepurposeof?

Firstly,theextractionprinciple:thesolubilityofbenzylalcoholandsodiumbenzoateinetherisdifferentfromtheextractionagentwithether,benzylalcoholwasextractedintoetherlayer,therebyseparatingthetwo.Theetherlayersweretreatedandthentheaqueouslayer,andthedistillationwasrecrystallizedtwomorepureisolatedproduct.

Theequation:C6H5CHO+NaHSO3=C6H5CH(OH)SO3NaSulfiteishappeningwiththecarbonyladditionreaction

Thereactioncanberemovednotbenzaldehyde3.Theremainingaqueoussolutionwasextractedwithdiethylether,acidifiedwithconcentratedhydrochloricacidtoneutralisthemostappropriate?Why?

4.Whyusefreshlydistilledbenzaldehyde?Long-termplacementofbenzaldehydecontainanyimpurities?Ifnotremove