Sulfated zirconia[1]

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Sulfated zirconia[1]

  1. 1. MetalsCeramicsPolymersCompositesZrO2synthesisPoornaprajna institute ofscientific Research ,BangaloreVijaykumar MarakattiSulfated Zirconia as a strong solid acidcatalyst for selected organictransformations
  2. 2. Outline of the talk Introduction. Synthesis of zirconia supported catalyst. Characterization. Structure. Acidity and super acidic properties of SZ. Application of SZ catalyst for organictransformations. Conclusions.
  3. 3. IntroductionMost of the industrially catalyzedprocess are based on acid catalyst. Different types of acid catalysts1. Heteropolyacids.2.Amberlyst3.Nafion-H4.Clays and Zeolites.5.Metal oxides.6. Anion modified metal oxide.(1980)ex:Sulfated zirconia, tungated zirconia
  4. 4. Metal oxide – ZrO2,TiO2,SnO2,Al2O3 etcAnion - MoO4-2 ,SO4-2,WO4-2 . Modification of metal oxide with anion generatenew active acid sites.Which are different then their individual acid sites.Combination of different metal oxide with differentanion gives a large no of catalyst with differentdistribution of acid sites.
  5. 5. Advantages of Anion Modified metal oxide Active over wide range of Temperature. Resistant to thermal extrusion. Low reaction temperature. Easy preparation and low cost.Disadvantages of Anion Modified metal oxide Sensitive to Reducing atmosphere. Forms acid if Water is present at hightemperature
  6. 6. SynthesisSulfated zirconiaa. Sol-GelH2SO4Zirconium n- PropoxidepropanolDrying 120 CCalcination 650 Cb. DecompositionZr(SO4)2SO4-2/ZrO2Journal of catalysis 150, 18-33(1994)
  7. 7. C. Precipitation and impregnation methodZrOCl2 NH4OHPH - 8Zr(OH)4Zr(OH)4120 CH2SO4SO4-2/ Zr(OH)4650 CSO4-2/ZrO2Acidity of catalyst depends Activation temperature. Precursorzirconiumsulufur sulfur content 1N,2N. PHSynthesisChemical review 109, 2185-2206(2009)
  8. 8. SynthesisTungstated zirconiaa. Impregnation method( dry , wet ,incipient)Ammonium tungatate + H2OZrO2 or Zr(OH)480 C 2hrStir for 4 hr110 C 6hrCalcined at 600CWOX/ZrO2Evaporation Co-precipitation Calcinations temperature. Preparation method.Catalysis letters 131, 122-128(2009)
  9. 9. Characterizationa. X-Ray Diffractometer10 20 30 40 50 60 70ZrO2SZ 1NSZ 1.5NSZ 2NWO3/ZrO2Intensity(a.u)ttPresent WorkWOX/ZrO2SZ-2NSZ-1.5NSZ-1NZrO2
  10. 10. b. FT-IR SpectraCharacterization900 1000 1100 1200 1300 1400995104411381212%TransmitanceWavenumber(cm-1)SZ 2NPRESENT WORK
  11. 11. C. TG-DTACharacterization575 C600 C650 CB.M Ready .etal Chemical review 109, 2185-2206(2009)
  12. 12. d. Textural propertiesCharacterizationmaterial SurfaceareaM2/gCrystallinesize(nm)Sulfur / WloadingZrO2 42 11.2 --SO4-2/ZrO2 100 7.3 2.3WO3/ZrO2 35 11.9 6Journal of molecular catalysis A. Chemical 109, 2185-2206(2009)
  13. 13. StructureB.M Ready .etal Chemical review 109, 2185-2206(2009)
  14. 14. ACIDITYmaterial NH3 desorbed(Ml/gram)ZrO2 5SO4-2/ZrO2 16WO3/ZrO2 9(TPD)
  15. 15. ACIDITY(FTIR- Pyridine)Catalyst B/L ratioSO42/ZrO2(1N) 1.6SO42/ZrO2(1.5 N) 1.03SO42/ZrO2(2 N) 0.92B/L Ratio : SZ 2N<SZ 1.5N< SZ1N.Present work1700 1650 1600 1550 1500 1450 1400ZrO2SZ-1NSZ-1.5NSZ-2NLB+LBAbsorption(a.u))wavenumber (cm-1)
  16. 16. Super acidity? Bronstead & lewis acidity. Ho indicator method. Colour change. Different acid sites. TPD Decomposition ofadsorbate molecule. adsorption on catalyticallynot active. CaO-NH3- at high T Skeletal isomerizationat low T.
  17. 17. Commercial application in hydroisomerization processn- Paraffins H2 iso-Paraffin- Aromatics – high octane number and C/H ratio- Branched HC – High octane Number- Hydro cracking is competing reaction.- Low temperature.- Bi-functional catalyst.- Pt/Alumina /Cl-.- Pt / SiO2-Al2O3.- Pt /Sulfated zirconia-HYSOPAR-100 ppm- WO3/ZrO2.Applications in organic transformations
  18. 18. Selective hydrolysis of cellulose into glucose Cellulose is the most abundant source of biomass. Enzyme catalyst – separation problems.
  19. 19. Reaction conditions: milled cellulose 45 mg, catalyst 50 mg, distilled water 5.0mL, 24 h.
  20. 20. Prins CyclizationOH HOOH+ Condensation of olefin with aldehyde. C-C bond forming reaction.Styrene Para formaldehyde 4-Phenyl 1,3-Dioxane Industrially high boiling solvent. Plasticizer, curing agent , Pigment dispersant Protecting group in organic synthesis. monomer and additives in polymer industry.U.S Patent -4,185 ,019 Jan.22(1980)
  21. 21. Catalyst Formaldehyde source YieldSulfuric acid Formaldehyde 75Heteropolyacids Paraformaldehyde 99Trifluromethane sulfonic acid Formaldehyde 92MoO3/SiO2 paraformaldehyde 73SO3H-SBA-15 Formaldehyde 100Indium bromideIonic liquidsparaformaldehyde 91Organic salt of heteropolyacids Formaldehyde 97Zeolites paraformaldehyde 40Sulfated zirconia paraformaldehyde 93Literature survey
  22. 22. Reaction conditions; 20 mmol styrene, 60 mmolparaformaldehyde, solvent :dichloroethane =10ml ;Catalyst: SZ-2N. Temp =80 C. Reaction time: 6hrCatalyst Timein hrsConversionWt%SelectivityWt%TONmmol/gramSO4-2/ZrO2 7 99.8 92 67.66WO3/ZrO27 96 85 60.14H-Beta(25) 7 22 88 14.14H-ZSM-5(38) 7 1 30 o.22H-Y(16) 7 1 50 o.36H-Mordenite(16) 7 2 46 0.67Cs2.5H0.5SiW12O40 1 97 68 49.33Montomorlonite-K-10 2 100 67 49.36Reaction conditions; 20 mmol styrene, 60 mmol paraformaldehyde, solvent :dichloroethane =10ml ;Catalyst : 7 wt % of reactant, Temp =80 C. Reaction time: 6hrScreening of catalyst
  23. 23. Effect of solventsolvent DielectricconstantAcceptorNumber(A.N)DonorNumber (D.N)Yield for4-Phenyl1,3 dioxaneNo solvent --- --- --- 56Tri ethyl amine 2.4 0Cyclohexane 2.6 47Toluene 2.4 641,2dichloro ethane 10.1 85Nitrobenzene 34.8 22Acetonitrile 36 0Isopropyl alcohol 18.3 33.8 21.1 0Reaction condition: 10 mmol styrene; 30 mmol Paraformaldehyde; 10 wt% of catalyst (reactant); Temp =80 C;solvent =5ml; reaction time =7 hr.The acceptor number( Lewis acidic) is obtained from the 31PNMR chemical shift values related to that of the1:1 adduct (C2H5)3PO-SbCl5 dissolved in 1,2 dichloroethane.The Donor number (Lewis base) defines the negative DH value for 1:1-adduct formation between sbCl5 and anelectron pair donor solvent in diluted solution in non coordinating solvent 1, 2-dichloro ethane.1.4 610 08.2 016.7 014.8 4.418.9 14.1
  24. 24. Catalyst Acidity B/LratioTime in (hr) conversion SelectivityBlank ---- 7hr 1.6 70Zr(OH)4 --- 7hr 1.7 72ZrO2 --- 7hr 2.3 74SZ-1N 1.6 3hr 87.8 74.6SZ-1.5N 1.04 3hr 76.3 78SZ-2N 0.92 3hr 73 887hr 99.8 92Sz-2Na --- 7hr -- --Sz-2Nb -- 7hr -- --Reaction conditions; 20 mmol styrene, 60 mmol paraformaldehyde, solvent :dichloroethane =10ml ;Catalyst: SZ-2N. Temp =80 C. Reaction time: 6hr.a- Aqueous Formaldehyde instead of paraformaldehyde.b – Aqueous Formaldehyde instead of paraformaldehyde, reaction temperature = 100 CSulfated zirconia catalyst
  25. 25. 60 80 100405060708090100Reaction Temperatureconversionofstyrene60708090100selectivityofdioxaneOptimization of reaction conditions.a. TemperatureReaction conditions; 20 mmol styrene, 60 mmol paraformaldehyde, solvent :dichloroethane=10ml ;Catalyst: SZ-2N. Temp =80 C. Reaction time: 7hr , catalyst weight -7 wt%.Reaction time -100C – 4hr
  26. 26. 3 5 7 96065707580859095100Percentage(%)catalyst (wt%)conversion of styreneselectivity for 4 phenyl 1,3 dioxaneb. Catalyst weightReaction conditions; 20 mmol styrene, 60 mmol paraformaldehyde, solvent :dichloroethane=10ml ;Catalyst: SZ-2N. Temp =80 C. Reaction time: 7hr
  27. 27. 1:1 1:2 1:3 1:4020406080100Percentage(%)Styrene:Paraformaldehyde mole ratioconversion of styreneselectivity for 4-Phenyl 1,3-dioxaneselectivity for cinnamyl alcoholC. Mole ratio of styrene :paraformaldehydeReaction conditions; solvent :dichloroethane =10ml ;Catalyst: SZ-2N. Temp =80 C. Reactiontime: 7hr , catalyst weight -7 wt%.
  28. 28. Leaching test0 1 2 3 4 5 6 7 8 9 100102030405060708090Percentage(%)Time (hr)conversion of styreneselectivity for 4-Phenyl1,3-dioxaneReaction condition: 20 mmol styrene: 60 mmol Paraformaldehyde; 7 wt% ofcatalyst (reactant); Temp =80 C; solvent: Dichloro ethane =10ml.
  29. 29. Recycling testCatalyst Yieldcycle 1 92cycle 2 91.4cycle 3 90cycle 4 89.810 20 30 40 50 60 70Cycle 4Cycle 3Cycle 2Cycle 1Intensity(a.u)2 Theta
  30. 30. SOOMechanism of reactionCOH HHOHHCOHZrOOOOOHOOCH2OHOOOHHSLBZrO2
  31. 31. conclusion Sulfated and tungstated zirconia catalyst weresynthesized by the precipitation and impregnationmethod. Characterization of sulfated zirconia by variousmethods were discussed. Prins reaction of styrene with Paraformaldehydeis carried out using Sulfated zirconia catalyst. Optimization study , effect of solvent and comparison ofother acid catalyst is done. SZ-2N showed good activity and selectivity for the prinsreaction.
  32. 32. Thank You

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