MetalsCeramicsPolymersCompositesZrO2synthesisPoornaprajna institute ofscientific Research ,BangaloreVijaykumar MarakattiSulfated Zirconia as a strong solid acidcatalyst for selected organictransformations
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.
IntroductionMost 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
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.
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
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.
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
Selective hydrolysis of cellulose into glucose Cellulose is the most abundant source of biomass. Enzyme catalyst – separation problems.
Reaction conditions: milled cellulose 45 mg, catalyst 50 mg, distilled water 5.0mL, 24 h.
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)
SOOMechanism of reactionCOH HHOHHCOHZrOOOOOHOOCH2OHOOOHHSLBZrO2
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.