Isomerizations of n-pentane and n-hexane over cesium hydrogen salt of 12-tungstophosphoric acid promoted by platinum
TL;DR: In this paper, isomerizations of n -pentane and n -hexane were carried out in the presence of hydrogen over Cs 2.5 H 0.5 PW 12 O 40 (Cs2.5) promoted with Pt by direct impregnation and mechanical mixing, and results were compared with similarly Pt-promoted H-ZSM-5 and sulfated zirconia.
Abstract: Isomerizations of n -pentane and n -hexane were carried out in the presence of hydrogen over Cs 2.5 H 0.5 PW 12 O 40 (Cs2.5) promoted with Pt by direct impregnation and mechanical mixing, and the results were compared with similarly Pt-promoted H-ZSM-5 and sulfated zirconia. The mechanical mixture of Pt/Al 2 O 3 and Cs2.5 showed the highest stationary activity and selectivity and the least deactivation for both reactions at a relatively low temperature (453 K) and a low H 2 pressure (pentane:H 2 :N 2 =0.05:0.05:0.9, hexane:H 2 :N 2 =0.05:0.2:0.75).
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TL;DR: In this paper, a review of self-assembled nanostructured materials and their catalytic applications is presented, focusing on mesoporous and nanoparticle-based catalysts.
Abstract: The purpose of this review is to highlight developments in self-assembled nanostructured materials (i.e., mesoporous and nanoparticle-based materials) and their catalytic applications. Since there are many available reviews of metal-based nanoparticles as catalysts, this review will mainly focus on self-assembled oxide-based catalytic materials. The content includes: (1) design and synthetic strategies for self-assembled mesoporous catalysts, (2) polyoxometalate (POM)-based nanocatalysts, (3) dendrimer-based nanocatalysts, and (4) shaped nanomaterials and catalytic applications. We show that controlled assembly of molecules, crystalline seeds, and nano building blocks into organized mesoscopic structures or controlled morphologies is an effective approach for tailoring porosities of heterogeneous catalysts and controlling their catalytic activities.
75 citations
Cites background from "Isomerizations of n-pentane and n-h..."
...The polyanions emulate the catalytic activities of other solid acids such as zeolites or superacids like SO4 2 /ZrO2 for isomerization of n-pentane and n-hexane and coking is circumvented in the gas phase reaction [126, 127]....
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...[127] Liu, Y....
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TL;DR: In this article, the catalysts were characterized by chemical analysis, nitrogen adsorption, XRD, SEM, TGA-DTA and IR spectroscopy, assuming that activation of the C-O bond in the DME molecule and formation of a metal-alkyl bond occurs in the presence of the strong acid sites and these strong acids sites act in conjunction with Rh carbonyl complexes, which are responsible for CO insertion and acetate formation.
Abstract: Acidic cesium salts of 12-tungstophosphoric acid promoted with rhodium, Rh/CsxH3-xPW12O40 (1.5≤x≤2 and Rh≥0.1%), were shown to be novel and effective catalysts for halide-free carbonylation of dimethyl ether (DME) to methyl acetate. The catalysts were characterized by chemical analysis, nitrogen adsorption, XRD, SEM, TGA-DTA and IR spectroscopy. Their behavior may be explained by assuming that (1) activation of the C—O bond in the DME molecule and formation of a metal-alkyl bond occurs in the presence of the strong acid sites and (2) these strong acid sites act in conjunction with Rh carbonyl complexes, which are responsible for CO insertion and acetate formation.
49 citations
TL;DR: In this article, the Pt+Cs2.5 (abbreviated as Pt+Cs2.4) isomerization of n-hexane and n-heptane was carried out over Cs 2.5H0.5PW12O40 in the presence of hydrogen at atmospheric pressure.
Abstract: Isomerization of n-hexane and n-heptane was carried out over Cs2.5H0.5PW12O40 (denoted by Cs2.5) promoted by Pt which was introduced by either impregnation of H2PtCl6 or mechanical mixing of Pt/Al2O3 and over non-promoted Cs2.5H0.5PW12O40 in the presence of hydrogen at atmospheric pressure. The reaction temperature studied was relatively low (typically 453 and 423 K for n-hexane and n-heptane, respectively) and the hydrogen pressure was also rather low (standard conditions: feed = n-alkane 0.05 atm, H2 0.20 atm, N2 balance; W/F = 40 g h mol−1). Results were compared with those obtained under the same conditions for other Pt-promoted solid acids, where particular attention was paid to the time courses of the reaction (initial vs. stationary performance). Both the activity and selectivity of Cs2.5 at the initial stage (after 5 min) increased by the addition of the Pt component. Pressure dependencies of the rate at the initial stage were approximately first and −0.5th orders in alkane and hydrogen, respectively. Most remarkable was the suppression of the deactivation during the reaction in the presence of both Pt and hydrogen. For example, the mechanical mixture of Pt/Al2O3 and Cs2.5 (abbreviated as Pt+Cs2.5) showed little deactivation and much improved selectivity; resulting in high stationary conversion and selectivity; e.g., 98.4 and 92.1% selectivities for n-hexane and n-heptane at the conversions of 58.6 and 39.4%, respectively. Most of the results were well explained by a classical bifunctional mechanism, although other mechanisms are not all excluded. As for the other solid acids, the initial activity of Pt-promoted SO4/ZrO2 was high, but decreased rapidly. The deactivation was small with Pt-promoted H-ZSM-5, but the activity was low. The stationary yields of isomerized products were higher for Pt-promoted beta zeolite and Al-pillared saponite (tested only for n-heptane), although higher reaction temperatures were necessary.
44 citations
TL;DR: In this article, the Pt-promoted Cs2H1PW12O40 pre-treatment under hydrogen flow at 473 K was used for n-hexane isomerization.
38 citations
TL;DR: In this article, the Fischer-Tropsch synthesis of F-T gasoline was performed in an atmospheric flow fixed-bed reaction system, where the mixture of Pt/Al2O3 and Cs2.5 showed the highest catalytic performance among various catalysts.
36 citations
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01 Dec 1980
TL;DR: In this paper, Asphaltene used the data of the Data Structural Group Analysis (DSGAA) to determine the effect of various factors on the stability or instability of the Crude Oil System.
Abstract: PART I: HISTORY, OCCURRENCE, AND RECOVERY History and Terminology Historical Perspectives Modern Perspectives Definitions and Terminology Native Materials Manufactured Materials Derived Materials Oil Prices Classification Classification Systems Miscellaneous Systems Reservoir Classification Origin and Occurrence Origin Occurrence Kerogen Properties Composition Classification Isolation Methods for Probing Kerogen Structure Structural Models Kerogen Maturation Exploration, Recovery, and Transportation Exploration Drilling Operations Well Completion Recovery Products and Product Quality Transportation New! Recovery of Heavy Oil and Tar Sand Bitumen Oil Mining Nonmining Methods PART II: COMPOSITION AND PROPERTIES Chemical Composition Ultimate (Elemental) Composition Chemical Components Chemical Composition by Distillation Fractional Composition Distillation Solvent Treatment Adsorption Chemical Methods Use of the Data Petroleum Analysis Petroleum Assay Physical Properties Thermal Properties Electrical Properties Optical Properties Spectroscopic Methods Chromatographic Methods Molecular Weight Use of the Data Structural Group Analysis Methods for Structural Group Analysis Miscellaneous Methods Asphaltene Constituents Separation Composition Molecular Weight Reactions Solubility Parameter Structural Aspects Structure of Petroleum Molecular Species in Petroleum Chemical and Physical Structure of Petroleum Stability or Instability of the Crude Oil System Effects on Recovery and Refining Completely Revised! Instability and Incompatibility Instability and Incompatibility in Petroleum Factors Influencing Instability and Incompatibility Methods for Determining Instability and Incompatibility Effect of Asphaltene Constituents PART III: REFINING New! Introduction to Refining Processes Dewatering and Desalting Early Processes Distillation Thermal Methods Catalytic Methods Hydroprocesses Reforming Isomerization Alkylation Processes Polymerization Processes Solvent Process Refining Heavy Feedstocks Petroleum Products Petrochemicals Completely Revised! Refining Chemistry Cracking Hydrogenation Isomerization Alkylation Polymerization Process Chemistry Completely Revised! Distillation Pretreatment Atmospheric and Vacuum Distillation Equipment Other Processes Completely Revised! Thermal Cracking Early Processes Commercial Processes Catalytic Cracking Early Processes Commercial Processes Catalysts Process Parameters New! Deasphalting and Dewaxing Processes Commercial Processes Dewaxing Processes Completely Revised! Hydrotreating and Desulfurization Process Parameters and Reactors Commercial Processes Catalysts Biodesulfurization Gasoline and Diesel Fuel Polishing Completely Revised! Hydrocracking Commercial Processes Catalysts Completely Revised! Hydrogen Production Processes Requiring Hydrogen Feedstocks Process Chemistry Commercial Processes Catalysts Hydrogen Purification Hydrogen Management Product Improvement Reforming Isomerization Alkylation Polymerization Catalysts Product Treating Commercial Processes Gas Processing Gas Cleaning Water Removal Liquids Removal Nitrogen Removal Acid Gas Removal Enrichment Fractionation Claus Process Completely Revised! Products Gaseous Fuels Gasoline Solvents (Naphtha) Kerosene Fuel Oil Lubricating Oil Other Oil Products Grease Wax Asphalt Coke Sulfonic Acids Acid Sludge Product Blending Petrochemicals Chemicals from Paraffins Chemicals from Olefins Chemicals from Aromatics Chemicals from Acetylene Chemicals from Natural Gas Inorganic Petrochemicals Synthesis Gas PART IV: ENVIRONMENTAL ISSUES New! Environmental Aspects of Refining Definitions Environmental Regulations Process Analysis Epilog New! Refinery Wastes Process Wastes Types of Waste Waste Toxicity Refinery Outlook Management of Refinery Waste New! Environmental Analysis Petroleum and Petroleum Products Leachability and Toxicity Total Petroleum Hydrocarbons Petroleum Group Analysis Petroleum Fractions Assessment of the Methods Conversion Factors Glossary Index *Each Chapter contains Introduction and Reference sections
2,226 citations
TL;DR: In this paper, a liquid phase alkylation of m -xylene or trimethylbenzene with cyclohexene was studied using heteropoly compounds and other typical solid acids as the catalysts.
322 citations
TL;DR: Sulfated zirconia is a strong solid acid that catalyzes isomerization of alkanes when metal crystallites are also present as mentioned in this paper, but it is only suitable for C4-C6 feeds and it has high cracking selectivities on Pt/ZrO2-SO4 and other solid and liquid acids.
309 citations
TL;DR: In this paper, the advances in acid catalysis by heteropolyacids are examined and data on the acidity of heteropolyACids are surveyed, and the characteristics of homogeneous and heterogeneous acid Catalysis by HPCs are discussed and its applied aspects are noted.
Abstract: The advances in acid catalysis by heteropolyacids are examined and data on the acidity of heteropolyacids are surveyed. The characteristics of homogeneous and heterogeneous acid catalysis by heteropolyacids are discussed and its applied aspects are noted. The bibliography includes 116 references.
296 citations
TL;DR: In this paper, the genesis of the high activity of zirconium oxide promoted by platinum and sulfate ion (Pt/SO 4 2− -ZrO 2 ) for skeletal isomerization of butane and pentane in the presence of hydrogen is studied in terms of the interaction of the catalyst with molecular hydrogen.
281 citations