Towards-Total-Design-of-Heterogeneous-Catalysts电子教案.ppt

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Towards Total Design of Heterogeneous Catalysts,Harold H.Kung,Chemical Engineering Department,Northwestern University,Evanston,IL 60208-3120,October 13,2003,What would one like to accomplish in total catalyst synthesis?,Shape of the cavity,Path to cavity,Ability to design and position ancillary groups,Complete atomic control of active site,(metal,oxide),Metal Crystallite Catalytic Active Phase,Surface arrangement of atoms,Composition,Nature of support,Location of crystallite on support(defect sites),Structure sensitivity,Electronic effect,Ligand,effect,Size-selective cluster beam deposition of Au,n,clusters on MgO,Heiz,Sanchez,Abbet,Schneider,Chem.Phys.262(2000)189.,MS signal of C,16,O,18,O in TPD after exposure to,18,O,2,and then CO,Aaron S.Eppler,Gnther Rupprechter,Lszl Guczi,and Gabor A.Somorjai,J.Phys.Chem.B 101(1997)9973.,Array of Pt on silica,Deposition of metal clusters using lithography,Insufficient control of shape,exact size,and atom locations;current limit on smallest size achieved.,P,-SO,3,2-,+M,n+,(aq),P,-SO,3,2-,M,n+,P,-SO,3,2-,M,n+,+NaBH,4,P,-SO,3,2-,/Mo,Preparation of uniform sized metal particles using functional resins,Corain,Centomo,Ferrari Meyer-Zaika,Schmid,Gold2003,October 2003.,Control of surface coordinative unsaturation sites of aluminum oxide(Al,2,O,3,)by synthesis,Active sites are surface exposed Al ions(Lewis acid sites).,Al,O,Al,O,O,Al,O,O,O,Active site,Al,Al,OR,OR,RO,RO,R,O,O,R,NRH,2,H,2,O,O,H,2,RN,Al,Al,O,O,O,H,2,RN,Strategy:use amine(Lewis base)to preserve Lewis acidity.,Al,OR,NRH,2,RO,RO,2,monomer,Can make monomer,Amine protection is retained,Final solid an active catalyst,Kozlov,Kung,Xue,and Kung,Angew.Chem.Int.Ed.42(2003)2415,Conversion of cyclopentene oxide in reaction with piperidine catalyzed by various aluminas.,PPD-Al,2,O,3,SG-Al,2,O,3,-200,SG-Al,2,O,3,-500-H,2,O-200,SG-Al,2,O,3,-500-H,2,O,PA,-Al,2,O,3,-500-H,2,O-200 PA-Al,2,O,3,-500-H,2,O,blank.,Xue,Kung,Kozlov,Popp,and Kung,Catal.Today,2003.,Generation of active site by building on a well-defined structure,001203c,J.M.Thomas,et al.Nature 398(1999)227;,Angew.Chem.Int.Ed.39(2000)2310.,Hexane()Oxidation,Two Co(III)ions in CoAlPO-18 at the desired distance apart in Co/P=0.1 samples.,CoAlPO-36 of larger pore structure and shape,produces much more 3-ol and 3-one.,Importance in controlling relative location of sites,Raja and Thomas,J.Molec.Catal.181(2002)3,29,Si NMR of(Si-O),n,oligomer units,Atom-by-Atom Synthesis of Metal-Oxygen Chain,Chang,Kung,and Kung,Chem.Comm.submittted.,Metal-Oxygen Backbone of Designed Sequence and Structure,O,Si,M,Molecular templating:,A.Katz and M.E.Davis,Nature 403(2000)286.,Introduce functional groups at specific locations in the cavity.,Molecules diffuse through silica wall into and out of cavity.,Preparing sites with predetermined spacing,Dufaud and Davis,JACS 125(2003)9403,Table 3.Synthesis of Bisphenol A with Sulfonic Acid Functionalized SBA-15 Silicas and,para,-Toluene Sulfonic Acid,a,per site yield of bisphenol A,b,p,p,/,o,p,molar ratio,catalyst,functional group,GC,c,NMR,d,GC,c,NMR,d,para,-toluene sulfonic acid,CH,3,aryl-SO,3,H,36,29,2,2.6,1-propane sulfonic acid,CH,3,CH,2,CH,2,-SO,3,H,9.6,e,n.d.,f,1.8,e,n.d.,11,SBA,Si-CH,2,CH,2,aryl-SO,3,H,13,11,3,3.0,9,SBA,Si-propyl-SO,3,H,8.8,8.4,10,6.4,10,SBA,Si-propyl-SO,3,H HO,3,S-propyl-Si,18,18,12,8.3,Vronique Dufaud,*,and Mark E.Davis,*,J.Am.Chem.Soc.,125(31),9403-9413,2003,What would one like to accomplish in total catalyst synthesis?,Shape of the cavity,Path to cavity,Ability to design and position ancillary groups,Complete atomic control of active site,Eliminated pore diffusion control,Little shape selectivity.,A.Corma,U.Diaz,M.E.Domine,V.Forn,s,Angew.Chem.Int.Ed.39(2000)1499.,(h00),K.Polborn and K.Severin,Chem.Commun.(1999)2481-2482.,Molecular Imprinting,Cat.4 made from 2;control cat.5 made from 1,R,P,R,P,Active,At rest,Molecular hinges to control accessibility of active sites,Figure 1 Molecular model of endoclucanase 12A and schematic model of the DMAAm-enzyme molecular switch.The red residues represent the catalytic glutamic acid side chains at the active site of EG 12A,the green residue is the Asn 55 position,the purple residue is the Ser 25 position,and the N-terminus is represented as the blue circle.,Tsuyoshi Shimoboji,Edmund Larenas,Tim Fowler,Allan S.Hoffman,*,and,Patrick S.Stayton,*,Bioconjugate Chem.,14,(3),517-525,2003,Figure 4 Characterization of ONPC enzyme activities for free DMAAm-EG 12A conjugates in solution at as function of polymer size and conjugation site.The enzyme activities were measured for 100 nM conjugates using ONPC(8mM)as a substrate and normalized to the activity of N55C or S25C EG12A controls as 100%at each temperature.EG 12A-M10,10 kDa DMAAm-EG12A conjugate;EG 12A-M6,6 kDa DMAAm-EG 12A conjugate;EG 12A-M3,3 kDa DMAAm-EG 12A conjugate;and EG 12A+M10,physical mixture of enzyme plus 10 kDa DMAAm.,Tsuyoshi Shimoboji,Edmund Larenas,Tim Fowler,Allan S.Hoffman,*,and,Patrick S.Stayton,*,Bioconjugate Chem.,14,(3),517-525,2003,Molecular Switching via Redox,Reduction by ascorbic acid,Oxidation with ammonium,persulfate,Conformational change monitored by circular,dichroism,S.,Zahn,and J.W.Canary,Angew,.Chem.Int.Ed.37(1998)305,-,V.Balzani,A.Credi,F.M.Raymo,J.F.Stoddart,Angew.Chemie Int.Ed.39(2000)3348,J.Rebek,Jr.Acc.Chem.Res.17(1984)258,V.Balzani,A.Credi,F.M.Raymo,J.F.Stoddart,Angew.Chemie Int.Ed.39(2000)3348,pH-Driven translocation of Ni(II)ion,Amendola,Fabbrizzi,Mangano,Pallavicini,Acc.Chem.Res.34(2001)488.,Translocation of metal ion is signaled by quenching/revival of the emission of fluorescent probe(anthracene substituent),Mesoporous benzene-silica,S.Inagaki et al,Nature,416(2002)304,Single-walled carbon nanotube,Single-walled metal-oxygen nanotube,Control of nanoreactor wall properties,M.C.Kung,3-D Macroporous material,After R.C.Schroden,C.F.Blanford,B.J.Melde,B.J.S.Johnson,A.Stein,Chem.Mater.13(2001)1074.,Dr.Ahn,Synthesis of wafers with a high density of micron size straight channels,Conclusion:,Shape of the cavity,Path to cavity,Ability to design and position ancillary groups,Complete atomic control of active site,Significant progress is made in recent years,and new revenues are discovered constantly,but more is needed to achieve complete synthesis.,