A green, efficient and reusable catalyst

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1、JournalofMolecularCatalysisA:Chemical234(2005)107110Bronstedacidicionicliquids:Agreen,efficientandreusablecatalyst¨systemandreactionmediumforFischeresterificationTrissaJoseph,SumanSahoo,S.B.Halligudi∗CatalysisDivision,NationalChemicalLaboratory,Pune411008,IndiaReceived19February2005

2、;receivedinrevisedform7March2005;accepted7March2005Availableonline11April2005AbstractBronstedacidicionicliquidcontainingnitrogen-basedorganiccations1-methylimidazoleand1-butyl-3-methylimidazoliumandinorganic¨anionsofthetypeBF−,PF−andPTSA−hasbeensynthesizedingoodyieldsandusedasacat

3、alystsandreactionmediumforFischer46esterificationofalcoholswithacids.ThesewerecharacterizedusingFTIRandNMRspectroscopy.Ionicliquidsascatalystaffordedgoodalcoholconversionandexcellentesterselectivity.FischeresterificationofaceticacidwithbenzylalcoholwithdifferentBronstedacidic¨ionicl

4、iquidswascarriedout.Maximumsubstrateconversion100%andproductselectivity100%wasobservedonusing[BMIM]+PTSA−ascatalystoveraperiodof2h.Theesterwaseasilyseparatedfromthereactionmixtureandtheionicliquidwasreusedfourtimesafterremovingwater.Nosignificantlossincatalyticactivitywasobservedon

5、recycling.©2005ElsevierB.V.Allrightsreserved.Keywords:Ionicliquid;Fischeresterification;Acids;Alcoholandreactionmedium1.Introductionneutralizationofhomogeneousacid.TheextensivedemandforcleanerenvironmentisforcingchemicalindustrytouseRoomtemperatureionicliquids(RTILs)haveattractedle

6、sshazardousmaterials.Toovercomethesedisadvantagesgreatresearchinterestduetothepotentialcommercialandeffortshavebeenmadetothedevelopmentofheterogeneousenvironmentaladvantagestheyofferoverexistingliquids.catalystssystems.Esterificationhasbeencarriedoutprevi-RTILsarecomprisedofionstha

7、tallowthemtopotentiallyouslyusingdifferentheterogeneousacidcatalystssuchasbehaveinaverydifferentmannertoconventionalmolecularresins[8,9],supportedmineralacid[10]heteropolyacidsliquidswhentheyareusedassolvents[13].Esterificationof[11,12],andzeolites[13]bydifferentgroups.Howeverthese

8、alcoholsbycarboxylicacidsisanimpo