电化学选择性氢化脱氯反应.ppt

银、钯催化的电化学选择性氢化脱氯反应,浙江工业大学/化学工程学院绿色化学合成技术国家重点实验室培育基地,徐颖华、马红星、丁旭芬、马淳安,Silver,Palladium-electrocatalyzedselectivehydrodechlorination,1,目录,1.银、钯催化的电化学选择性氢化脱氯反应简介,2.多氯吡啶甲酸的电化学选择性氢化脱氯反应,3.其他多氯有机物的电化学选择性氢化脱氯反应,4.总结和展望,ZhejiangUniversityofTechnology,2,1.银、钯催化的电化学选择性氢化脱氯反应简介,有机合成：合成部分氯代有机物作为药物中间体或原料药；要求:区域选择性脱氯。,1.1.主要用途及要求,ZhejiangUniversityofTechnology,RondininiS.,etal.ElectroreductionofHalogenatedOrganicCompounds,2010,279;AlonaoF.,etal.Chem.Rev.,2002,102(11):4009-4091.,环境保护：降解环境中存在的高毒、难降解氯代有机物；要求：化学选择性脱氯。,3,1.2.催化原理,IsseA.A.,etal.J.Phys.Chem.C,2009,113:14983;WangA.,etal.J.Am.Chem.Soc.:2010,132:9534.,DaboP.,etal.Environ.Sci.Technol.,2000,34:1265;ChenG.,etal.J.Phys.Chem.B,2006,110:4863.,Fig.1.1Thehydrodechlorinationmechanismonsilverelectrode,Fig.1.2Thehydrodechlorinationmechanismonpalladiumelectrode,4,2.多氯吡啶甲酸的电化学选择性氢化脱氯,化工学报,2010,61:699.,ZhejiangUniversityofTechnology,5,Fig.2.1CVsof3,5,6-T(a)atfourelectrodesinaN2-saturated0.25MPBSatpH=3,(b)ataAg(r)electrodeinaN2-saturated0.5MH2SO4(pH=0.2),a0.5MNaOH(pH=13.3)aqueoussolution,and0.25MPBSofthreedifferentpHvalues(3,7,and11);scanratev=50mVs-1,T=297K.,Electrochim.Acta,2015,151:284;ZL201410264884.1,ZhejiangUniversityofTechnology,2.1.银催化,pH=3,Ag(r),6,Table2.1Electrochemicalreductionof3.33mM3,5,6-TinaN2-saturated0.5MH2SO4(pH=0.2),a0.5MNaOH(pH=13.3)aqueoussolution,and0.25MPBSofthreedifferentpHvalues(3,7,and11)at297Konfivecathodes.,a2Fmol-1of3,5,6-Twereconsumedintheall10electrolysisexperiments.bCurrentefficiencycalculatedwithrespecttotheproduced3,5-D.c3,5-Dand3,6-Dselectivitycalculatedwithrespecttotheconverted3,5,6-T.,ZhejiangUniversityofTechnology,7,Fig.2.2Productselectivityandcarbonmassbalanceduringtheelectrochemicalreductionof42.5mM3,5,6-Tat297K.Catholye:30mL0.25MPBSatpH=3.Cathode:Ag(r)meshelectrodes(2.5cm3cm).,ZhejiangUniversityofTechnology,8,ZhejiangUniversityofTechnology,Fig.2.3EffectsofpHontheselectivityforhydrodechlorinationofTeCPonsilvercathodes.,9,Fig.2.5LSVofNifoam,Agmesh,Cufoamelectrodes,andPd/Nifoam,Pd/Agmesh,Pd/Cufoamelectrodesina0.5MNaOHaqueoussolution,v=5mV/s,withtwoconcentrationsof3,6-D,Temperature:25.,Fig.2.4SEMofNiandPd/Nifoam,AgandPd/Agmesh,CuandPd/Cufoam.,ZL201510401434.7;ZL201510401039.9.,ZhejiangUniversityofTechnology,2.2.钯催化,Pd/Nifoam,Nifoam,Agmesh,Cufoam,Pd/Agmesh,Pd/Cufoam,10,Table2.2EffectofelectrolytecompositionontheECHdechlorinationof0.25M3,6-D.a,aCathode:aPd/Nifoam(Projectedarea:26cm2,Pdloading:2.25mg/cm2).cCEwascalculatedwitht=6h.d3,6-Dwasaddedintothecatholyteinadividedfashionduringthefirsthourofelectrolysisduetoitspoorsolubility.,ZhejiangUniversityofTechnology,11,Fig.2.6EffectofpHonproductselectivityandCEduringtheECHdechlorinationof3,6-D.Cathode:aPd/Nifoam;Catholyte:(AandA)50mL1.25MNaOH+96mM3,6-D,andB(B)50mL0.75MH2SO4+96mM3,6-D+20%v/vEthanol;CEwascalculatedwitht=1,2,3,4,5or6.0h.,ZhejiangUniversityofTechnology,12,Scheme1ProposedmechanismsfortheECHdechlorinationof3,6-D.,ZhejiangUniversityofTechnology,13,Fig.2.7EffectsofcathodecatalystsandpHontheselectivityforhydrodechlorinationofTeCP.,ZhejiangUniversityofTechnology,14,3.其他多氯有机物电化学选择性氢化脱氯,3.1.三氯甲基苯,Fig.3.1CVof5.0mMbenzenyltrichlorideandbenzylchloride,inCH3CN+0.1mMTBAPonAgelectrode(2mm),at298K,v=100mVs-1,T=20.,物理化学学报,2013,29:973.,ZhejiangUniversityofTechnology,Agelectrode,Agelectrode,15,Table3.1ElectroreductionofbenzenyltrichlorideatAgmesh(2.53.0cm2),in40mLcatholyte(CH3CN+0.1mMTBAP+5.0mMbenzenyltrichloride),at20.,aAppliedpotentialvs.Ag/Ag+.bInpresentof1MCH3COOH,ZhejiangUniversityofTechnology,16,3.2.氯乙酸,Fig.3.2CVsofthreeelectrodesinblank0.5MNaOH(1(blue),2,3(red)andinpresentof50mMTCAA(1(black,redandgreen)or50mMMCAA(2,3(black),v=50mVs-1,T=298K.,J.Electroan.Chem.,2012,664:39.,ZhejiangUniversityofTechnology,CCl3COOH(TCAA),CH2ClCOOH(MCAA),Ag(p),Ag(r),17,Fig.3.3CVsofAg(r)electrodeinblankaqueoussolutions+(1)0.05MTCAA,(2)0.05MDCAA,(3)0.05MMCAA,(4)nothing,at50mVs-1.,ZhejiangUniversityofTechnology,1-CCl3COOH(TCAA)2-CHCl2COOH(DCAA)3-CH2ClCOOH(MCAA)4-blank,pH=2.2,pH=7,18,Fig.3.4ThereductionofTCAA(0.05M)usingAg(r)electrode,at298K,inaqueoussolutionsof(1)0.5MH2SO4,(2)0.5MNa2SO4and(3)0.5MNaOH.,Fig.3.5Currentefficiencyforthereductionof0.05MTCAA,usingAg(r)electrode(2cm3cm0.1cm),usingappliedcurrent110mA,(1)0.5MH2SO4,(2)0.5MNa2SO4and(3)0.5MNaOH.,ZhejiangUniversityofTechnology,19,Fig.3.6SEM:(1)Ag(p)electrode,(2)Pd/Ag(p)electrode,(3)Ag(r)electrode,and(4)Pd/Agelectrode.,3.3.2,4-二氯苯氧乙酸,Electrochem.Commun.,2009,11:2133;Electrochim.Acta,2013,96:90.,ZhejiangUniversityofTechnology,Ag(p)electrode,Ag(r)electrode,Pd/Ag(p)electrode,Pd/Ag(r)electrode,20,Fig.3.7CVsoffiveelectrodesinblank0.5MNaOH(a,b,c,d(black),f(black)andinpresenceof25mM2,4-D(d(red,green),e,f(red),=50mVs-1.,ZhejiangUniversityofTechnology,21,Table3.2Electroreductionsof25mM2,4-Din0.5MNaOH,onfourdifferentelectrodes(34cm2).PAA:phenoxyaceticacid;ClPAA:2-Cland4-Cl-phenoxyaceticacid;2,4-D:2,4-diCl-phenoxyaceticacid.,ZhejiangUniversityofTechnology,22,ZhejiangUniversityofTechnology,Fig.3.8TheproductselectivityandcarbonmassbalanceduringtheECHdechlorinationof2,4-D.,Fig.3.9ThehydrodechlorinationmechanismonPd/Ag(r)electrode,23,4.总结和展望,ZhejiangUniversityofTechnology,通过改变催化剂类型和电解液pH，很多氯代有机物氢化脱氯反应的选择性有望得到有效控制；银催化剂适合需要控制区域选择性的氢化脱氯反应，钯催化