棉籽油酯交换制备生物柴油固体碱催化过程研究

204No.4Vol.2020068JournalofChemicalEngineeringofChineseUniversitiesAug.20061003-9015(2006)04-0593-05,(,100084)()-MgOCaOMgO-Al2O3CaOMgO-Al2O323012:12%(wt)3h90%CO2-TPDCaOMgO-Al2O3TQ645.8ABiodieselfromTransesterificationofCottonSeedOilbySolidBasesCatalysisCHENHe,WANGJin-fu(DepartmentofChemicalEngineering,TsinghuaUniversity,Beijing100084,China)Abstract:Methylesters(biodiesel)wereproducedbytransesterificationofcottonseedoilwithmethanolinthepresenceofsolidbasesasheterogeneouscatalyst.ThesolidbasecatalystsMgO,CaOandMgO-Al2O3werepreparedrespectivelyfromthedissociationofbasicmagnesiumhydroxide,calciumcarbonateandhydrotalciteatelevatedtemperature.TheexperimentsshowthattheCaOandMgO-Al2O3havehighcatalyticactivityfortransesterificationreaction,andtheyieldofmethy1estersreachesover90%undertheconditionof230°C,methanol/oilmoleratioof12,andcatalystdosage(catalyst/oil)of2%afterreaction3h.TheCO2-TPDprofilesshowthatthecatalystsCaOandMgO-Al2O3havehighbasestrengthandmoreamountofbasesite,whichimplicatesthosecatalystswillhaveahighercatalyticactivity.Keywords:solidbases;biodiesel;methylesters;cottonseedoil;transesterification1()[1](SOx)850[2]2005-01-042005-05-23(973)(2004CB719706)(1978-)[e-mail]59420068313323333TriglyceridesCHOHDiglyceridesRCOOCHDiglyceridesCHOHMonoglyceridesRCOOCHMonoglyceridesCHOHGlycerineRCOOCH⇔⇔⇔()(KOH)[3,4]100~150100%[5,6]MgOCaO[7]MgO-Al2O3[8](MgOCaOMgO-Al2O3)22.1100mL1mol⋅L−1Mg(NO3)2200mL1mol⋅L−1Mg(OH)2Mg(OH)26003hMgOCaO100mL1mol⋅L−1Ca(NO3)2100mL1mol⋅L−1Na2CO3CaCO39002hMgO-Al2O380mLH2O0.16molNaOH0.04molNa2CO30.06molMg(NO3)2·6H2O0.02molAl(NO3)3·9H2O80mLH2OpH9~106518h5504hMgO-Al2O32.2XRDD/max-5AXRDCuKα50kV30mA0.2º⋅min−1(2θ)BETNOVA-4000CO2-TPDHe1h50CO21hHe30min10⋅min−1(N250mL⋅min−1)9002.3250mL()2.4(10A)TGDGMGEODS2(250mm×4.6mm)40:1:1(v/v)1mL⋅min−1Acros33.1XRD(1)Mg(OH)2CaCO3204595MgOCaOMgO-Al2O3MgOXRDMgO-Al2O3MgOAlMgOMgCO2-TPD2CaOyMgOMgO-Al2O3CO2423K523KMgO-Al2O3MgOCaO723KCO2CaOMgOMgO-Al2O31BETTPDXRDMgO-Al2O3Al2O3MgOMgO-Al2O3MgOMgO-Al2O3CO2CaOMgO-Al2O3MgOCO23.234(TG)(ME)/12:12302(wt)MgOTG(DG)(MG)CaOMgO-Al2O3CaOMgO-Al2O33hTG95%ME90%3.352CaO1BETTable1BETspecificsurfaceareaofsolidbasesCatalystsBETsurfacearea/m2⋅g−1MgO67.78MgO-Al2O3220.51CaO13.68102030405060708010203040506070801020304050607080MgOCaOMgO-Al2O3θ/degrees1XRDFig.1XRDpatternofsolidbases400600800100040060080010004006008001000MgOCaO1/2MgO-Al2O3Temperature/K2CO2-TPDFig.2TPDprofilesofcarbondioxidedesorbedfromsolidbases050100150200406080100MgO-Al2O3MgOCaOConversionofTG/%Time/min3Fig.3Conversionoftriglyceridesversusreactiontimefordifferentsolidbasecatalysts050100150200250-20020406080100MgO-Al2O3MgOCaOYieldofME/%Time/min4Fig.4Methylesteryieldversusreactiontimefordifferentsolidbasecatalysts596200682Table2EffectoftemperatureonproductionoftransesterificationProductionwithcatalystCaO/%(wt)ProductionwithcatalystMgO-Al2O3/%(wt)Temperature/TGDGMGMETGDGMGME2004.53.33.189.110.96.85.576.82102.92.82.591.885.44.583.12202.12.31.993.75.63.43.187.923012.01.895.24.42.52.490.7MgO-Al2O3CaO(200)TG95%90%MEMgO-Al2O3TGDGMGME(20080%)3:16(12:1)3.47MgO-Al2O3CaO5CaO80%CaOMgO-Al2O3MgO-Al2O33.5CaOMgO-Al2O3(230)[9]CH3O−CH3O-CH3OHCH3O−CaOMgO-Al2O3MgO-Al2O3MgOMgO-Al2O3MgOMgO4(1)2002102202304060801006080100CaOMgO-Al2O3CaOMgO-Al2O3ConversionofTG/%YieldofME/%Temperature/512:12(wt)Fig.5EffectoftemperatureonTGconversionandMEyieldwithsolidbasesascatalysts.Catalyst:2%(wt),reactiontime4h,moleratioCH3OH/oil=12:1061218246080100MgO-Al2O3CaOYieldofME/%Methanol/oilratio6Fig.6Effectofmethanol/oilmoleratioonMEyield.Temperature:230,catalyst:2%(wt),reactiontime4h.Catalystreusedtimes712:12%(wt)Fig.7Stabilityofsolidbasesascatalysts.Temperature:230,catalyst:2%(wt),reactiontime4h,moleratioCH3OH/oil=12:1123454060801006080100CaOMgO-Al2O3CaOMgO-Al2O3ConversionofTG/%YieldofME/%204597CaO(2)CaO23012:12%(wt)95%MgO-Al2O390%(3)CaOMgO-Al2O3[1]AnjanaS,RamP.Triglycerides-baseddieselfuels[J].RenewableandSustainableEnergyReviews,2000,4(2):111-133.[2]WANGRui-yuan().LipidindustryofChinain2003(2003)[J].ScienceandTechnologyofCereals,OilsandFoods(),2004,12(4):1-3.[3]SHENGMei(),WUGuo-ying(),XUGe,etal().Preparationofbiodieselfromrapeseedoil()[J].JChemEngofChineseUniv(),2004,18(2):231-236.[4]DraganN,RupertP,ManfredW,RichardG.Preparationofrapeseedoilesterofloweraliphaticalcohols[J].JAOCS,2000,77(3):275-279.[5]PetersonmGR,ScarrahWP.Rapeseedoiltransesterificationbyheterogeneouscatalysis[J].JAOCS,1984,61(10):1593-1597.[6]GalenJ,MohanprasadA,EricJ,PratikJ,MichaelJ.Transesterificationofsoybeanoilwithzeoliteandmetalcatalysts[J].AppliedCatalysisA:General2004,257(2):213-223.[7]WeiTong,WangMou-hua,WeiWei,etal.Effectofbasestrengthandbasicityoncatalyiticbehaviorofsolidbasesforsynthesisofdimethylcarbonatefrompropylenecarbonateandmethanol[J].FuelProcessTechnology,2003,83(1-3):175-182.[8]NodaP,PérezCA,HenriqueCA,MonteiroJ.HydrotacilteasprecursorsforMgAl-mixedoxidesusedascatalystsontheadolcondensationofcitralwithacetone[J].AppliedCatalysisA:General,2004,272(1-2):229-240.[9]EckeyEW.Esterificationandinteresterification[J].JAOCS,1956,33(3):57