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Monday, August 3, 2020 | History

2 edition of Studies of skeletal hydrocarbon reactions on platinum/zirconia based superacid catalysts found in the catalog.

Studies of skeletal hydrocarbon reactions on platinum/zirconia based superacid catalysts

Michael Richard Smith

Studies of skeletal hydrocarbon reactions on platinum/zirconia based superacid catalysts

by Michael Richard Smith

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  • 1 Currently reading

Published by University College Dublin in Dublin .
Written in English

    Subjects:
  • Catalysis.,
  • Platinum catalysts.,
  • Zirconium oxide.

  • Edition Notes

    Statementby Michael Richard Smith.
    ContributionsUniversity College Dublin. Department of Chemistry.
    The Physical Object
    Paginationvi, 262p. :
    Number of Pages262
    ID Numbers
    Open LibraryOL16573884M

    Zirconia Based Ceramic, In-Cylinder Coatings and Aftertreatment Oxidation Catalysts for Reduction of Emissions from Heavy Duty Diesel Engines Diesel engines are coming under stricter requirements to reduce emissions. particularly those of particulates and nitrogen oxides (NOx). Recently, the U. S. EPA put into place staged requirements. Zirconium dioxide (ZrO 2), sometimes known as zirconia (not to be confused with zircon), is a white crystalline oxide of most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite.A dopant stabilized cubic structured zirconia, cubic zirconia, is synthesized in various colours for use as a gemstone and a diamond simulant.

    Some studies have demonstrated a potential problem in sandblasting the internal surface with respect to crack growth, while others have shown an improvement in properties. 11, The following case demonstrates the use of zirconia as a framework material. Overall, zirconia has proven to be a strong and reliable framework material. Sulfated zirconia has attracted extensive attention due to its superactivity to isomerize alkane and alkenes. Platinum or iron/manganese promoted sulfated zirconia has been shown to increase the reaction rate. These catalysts are normally activated to °C in air before use. Through on-line analysis of evolved gas species during dynamic heating of the catalysts, some significant.

    Ceria is widely used in catalytic converters for exhaust gases because of its exceptional redox properties. The material is able to store oxygen during the lean phase (i.e., excess of oxygen) and to give oxygen back to metal particles during the rich phase (when there is virtually no O 2 in the gas phase); this is the so‐called oxygen storage capacity (OSC) of ceria. s: The zirconia dispersion-strengthened platinum thermocouple materials were successfully fabricated by powder metallurgic method. It was studied the zirconia grains influences on platinum materials. The results of the study show that its density is g/cm3 and its relative density is %. Its tensile strength obvious overtop pure platinum, the maximum tensile strength is MPa.


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Results

Results

Studies of skeletal hydrocarbon reactions on platinum/zirconia based superacid catalysts by Michael Richard Smith Download PDF EPUB FB2

~ APPLIED CATALYSIS A: GENERAL ELSEVIER Applied Catalysis A: General () Skeletal reactions of hydrocarbons on platinum/sulphated zirconia superacid catalysts having an oxidative redispersion stage in their preparation A polar mechanism of C-C bond scission on platinum affects selectivity M.R.

Smitha, J.K.A. Clarkea, G. Fitzsimonsb, J.J. Rooneyb'* Cited by: 5. Request PDF | Comparative study of n-pentane isomerization over solid acid catalysts, heteropolyacid, sulfated zirconia, and mordenite: Dependence on hydrogen and platinum addition | Skeletal.

The preparation of platinum-zirconium alloy catalyst systems is described and their characterisation reveals interesting structures. Studies on a number of catalytic reactions indicate that these alloy systems have catalytic properties significantly different from platinum on zirconia systems.

In addition these catalysts do not segregate into platinum and zirconia or zirconium carbide either. Reaction mechanism of skeletal isomerization of n-butane over sulfated zirconia (SZ), CsHPW12O40 (Cs) and H-form mordenite (H-MOR) catalysts was studied using 13C MAS NMR with 13C-labeled.

The crystalline structure of Zr(SO 4) 2 /γ-Al 2 O 3 calcined in air at different temperatures for 2 h were checked by X-ray diffraction. For the Zr(SO 4) 2 /γ-Al 2 O 3, as shown in Fig. 3, X-ray diffraction data indicated only γ-Al 2 O 3 phase at – °C.

However, at °C, a tetragonal phase of ZrO 2 was observed due to the decomposition of zirconium sulfate, showing good Cited by: Skeletal reactions of hydrocarbons on platinum/sulphated zirconia superacid catalysts having an oxidative redispersion stage in their preparation A polar mechanism of C—C bond scission on platinum affects selectivity.

Applied Catalysis A: General(), DOI: /SX(97) hazardous acids. The development of new processes based on strong solid acid catalysts to replace HF and H2S04 is strongly needed for environmental as well as safety considera tions [51].

Among solid superacids studied so far [14,52] sulfate supported zirconia is highest in acid strength. S/Zr02 materials impregnated with noble metal. Studies on the employed cata-lysts for this reaction showed that Sulfated Zirconia (SZ), as an environmentally friendly catalyst, was believed to be the most promising catalyst among the solid acids due to low-temperature hydrocarbon skeletal rearrangements for thermodynamic consider-ation [6,7,].

Sulfated zirconia as a solid super acid. Sulfated Zirconia (SZ) has opened up a very interesting area for application predominantly as catalyst for various acid catalyzed organic syntheses and transformation reactions.

Catalytic properties of SZ vary with methods of preparation. Lot of efforts is made to modify SZ to increase reactivity and stability of the catalyst.

This review focuses on the individual synthesis routes to prepare. On the other hand, some solid superacid catalysts are known to catalyze the skeletal isomerization of hydrocarbons at low temperatures, but these catalysts tend to deactivate quickly. In particular, sulfated zirconia (SZ) is a very strong solid acid that is able to catalyze the isomerization of n -hexane at room temperature, even in the absence.

A solid strong acid catalyst useful for hydrocarbon reactions, especially for the skeletal isomerization of paraffinic hydrocarbons is provided by supporting sulfate (SO 4) and at least one member selected from Group VIII metals on a support consisting of hydroxides and oxides of Group IV metals and Group III metals and mixtures thereof and then calcining and stabilizing the catalyst.

The twelfth Congress on Catalysis was held in Granada (Spain) under the auspices of the International Association of Catalysis Societies and the Spanish Society of Catalysis. These four-volume Proceedings are the expression of the Scientific Sessions which constituted the main body of the Congress.

They include 5 plenary lectures, 1 award lecture, 8 keynote lectures, oral presentations and. Abstract.

The objective of this study is to report usage of laboratory-prepared zirconia-based samples, normal zirconia (ZD), calcined zirconia at K (ZC) and sulfated and calcined zirconia at K (SZC), as potential catalysts for the oxidative removal of.

Pt/SO4/ZrO2/Al2O3 acid catalyst during n hexane isomerization in a hydrogen environment. EXPERIMENTAL Preparation of Catalysts Our studies were conducted using platinum free acid catalysts γ Al2O3 and SO4/ZrO2/Al2O3, and platinum supported catalysts Pt/Al2O3 and Pt/SO4/ZrO2/Al2O3.

Their chemical compositions and denotations are listed in Table 1. at 2θ = ˚, ˚. In all these catalysts zirconia main-tains its monoclinic phase. SEM micrographs of fresh samples, reported in. Figure 2, show the homogeneity of the crystal size of monoclinic zirconia.

The micrographs of Pt/ZrO. 2, Pd/ZrO. 2, Pt-Pd/ZrO. and Bi. 3 /ZrO. reveal that the active metals are well dispersed on. Zirconia based ceramics are chemically inert materials, allowing good cell adhesion, and while no adverse systemic reactions have been associated with it.

(Ichikawa et al., ). However, particles from the degradation of zirconia at low temperature (LTD) or from the manufacturing process can be released, promoting an immune localized.

A conspicuous interest has been devoted to these materials thanks to their great activity as catalysts in different organic reactions, such as hydrocarbon skeletal isomerization or alkylation of paraffins, in particular superacidic Zr, Ti, Fe, Hf, Si, Sn and Al metal oxides have been investigated in.

@article{osti_, title = {Chemistry of catalytic hydrocarbon conversions}, author = {Pines, H.}, abstractNote = {The catalytic conversion of hydrocarbons is used for the production of both high octane gasoline and petrochemicals. The chapters are arranged according to the type of catalyst used in the various reactions.

Chapters cover: acid-catalyzed reactions, base-catalyzed reactions. Restart reaction studies and reaction rate studies using platinum surfaces precovered with carbonaceous overlayers containing carbon were used to investigate the catalytic activity and selectivity of carbon-covered platinum in hydrocarbon hydrogenation, dehydrogenation, and skeletal.

The physicochemical properties and catalytic activity of pure and sulfated titanium oxide (TiO2 and) is described in this work. Titanium hydroxide synthesized by the sol-gel method was impregnated with a 1 N H2SO4 solution, varying amount of sulfate ions in the range from 10 to 20 wt%. Pure and modified hydroxides were calcined at °C for 3 h and then characterized by TGA-DTG, XRD, BET, FT.

2. Reactions of butane and isobutane catalyzed by zirconium oxide treated with sulfate ion. Solid superacid catalyst. J Am Chem Soc. ; – doi: /jaa Corma A, Martinez A, Martinez C. Influence of process variables on the continuous alkylation of isobutane with 2-butene on superacid sulfated zirconia catalysts.

The formation rate and primary particle size of monoclinic, hydrous zirconia particles produced by the hydrolysis of various ZrOCl 2 solutions (with and without the addition of HCl, NH 4 OH, NaCl, CaCl 2, or AlCl 3) were measured to clarify the effects of the H + and Cl − ion concentrations on the nucleation and crystal‐growth processes of primary particles of hydrous zirconia.

In an alternative system, metal oxide-based catalysts are applied for the isomerization of light naphtha at temperatures between and K.

2 As environmentally benign catalysts, inorganic solid acids have gained much attention in recent years due to recognized advantages of heterogeneous catalysts, like simplified product isolation, mild.