Elements Of X Ray Diffraction

Thermal decomposition of ammonium perchlorate

(1990). Conversion of Methane by Oxidative Coupling. Catalysis Reviews: Vol. 32, No. 3, pp. 163-227.

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Conversion of Methane by Oxidative Coupling

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Analysis Synthesis And Design Of Chemical Processes

Natural gas is an abundant resource in various parts of the world. Methane is the major component of natural gas, often comprising over 90 mol% of the hydrocarbon fraction of the gas. Methane itself is primarily used as a fuel, while the nonmethane components can be separated and used as feedstocks for the production of chemicals or liquid fuels. In many cases, however, natural gas reserves are found in locations distant from their place of utilization. Since it is not generally economical to transport liquefied natural gas, efficient methods are needed to convert methane into transportable liquid products. A possible route is oxidative dimerization of methane followed by oligomer-ization of the C2 products.

Oxidative Coupling of Methane to Higher Hydrocarbons

Vanadium pentoxide catalysts supported on γ-alumina (1 - 50 mole %) were prepared by impregnation method and calcined at 400 and 680 °C for 4 h. The structure of the original and calcined samples was characterized by DTA and X-ray diffraction. The electrical conductivity measurements of the calcined samples reveal that the conductance increases while the Fermi potential decreases on increasing V 2 O 5 content up to 50 mole %. The catalytic dehydration of isopropanol was carried out at 250 °C using a flow system. The results showed an observable increase in the extent of catalytic dehydration of the alcohol on increasing V 2 O 5 content from 5 mole % to 50 mole % with the samples calcined at 400 °C. The catalysts calcined at 680 °C were found to exhibit maximum activity at the composition of 20 mole % V 2 O 5 . Above the maximum a sharp decrease in the conversion and the yield towards propylene was found due to formation of aluminium vanadate, i.e. AlVO 4 spinel. The low activity associated with the existence of this spinel was correlated with the sharp decrease in the Fermi potential.

Influence of the Formation of Aluminium Spinel, AlVO 4 , on the Catalytic Activity of V 2 O 5 Supported on γ-Alumina

Molybdenum oxide catalysts doped or mixed with (1–50) mol% Fe3+ ions were prepared. The structure of the original samples and calcined at 400 °C were characterized using DTA, X-ray diffraction, and IR spectra. The measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mol%. The activation energies of charge carriers were determined in presence and absence of alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mol% Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted between the catalyst composition and their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

Role of the structure and electronic properties of Fe2O3-MoO3 catalyst on the dehydration of isopropyl alcohol

Vanadium oxide catalysts doped or mixed with 1-50 mole % Fe 3+ ions were prepared. The structure of the original samples and those calcined from 200 up to 500 °C were characterized by TG, DTA, IR and X-ray diffraction. The S BET values and texture of the solid catalysts were investigated. The catalytic dehydration-dehydrogenation of isopropanol was carried out at 200 °C using a flow system. The results obtained showed an observable decrease in the activity of V 2 O 5 on the addition of Fe 3+ ions. Moreover, Fe 2 V 4 O 13 is the more active and selective catalyst than FeVO 4 spinels. The results were correlated with the active sites created on the catalyst surface.

Physicochemical and Catalytic Properties of Spinels Formed by Solid-Solid Interaction Between Fe2O3and V2O5

Conversion of methanol to dimethyl ether (MTD) has known to be one of the main routes for the production of a clean bio-fuel, i.e., dimethyl ether (DME). However, efficient, selective, and stable catalyst is highly required for production of DME especially at relatively low temperature. Herein, aluminum phosphate nanocatalysts were fabricated by a co-precipitation method in the presence of triethylamine (TEA) as a surfactant. Thermal, structural, spectroscopic, morphological and texture properties of the catalysts were characterized by thermal analyses (TG–DTA), X-Ray diffraction (XRD), Fourier transform infrared (FTIR), high resolution transmission electron microscopy (HR-TEM) and N2-sorption analyses. In addition, the acidity of these catalysts was evaluated by isopropyl alcohol dehydration and chemisorption of basic probes. Results of acidity and pyridine-TPD indicated that these catalysts possessed Brϕnsted acidic sites of weak and intermediate strengths. The results of catalytic activity demonstrated that aluminum phosphate nanocatalyst (AP1T1) calcined at 400 °C exhibited the best catalytic performance for methanol dehydration into DME with a conversion of 100% and a 100% selectivity at 250 °C. In addition, this catalyst (AP1T1) exhibits a unique behavior where its catalytic performance only decreases by 10% upon increasing the % of methanol in the reacting feed to 35%. Moreover, it possessed excellent long-term stability with almost the same efficiency after a period of 120 h. The observable catalytic activity of these catalysts was well linked to the catalyst acidity and the activation energy.

Abd El-Aziz A. Said

Papers

Influence of the Formation of Aluminium Spinel, AlVO 4 , on the Catalytic Activity of V 2 O 5 Supported on γ-Alumina

Role of the structure and electronic properties of Fe2O3-MoO3 catalyst on the dehydration of isopropyl alcohol

Physicochemical and Catalytic Properties of Spinels Formed by Solid-Solid Interaction Between Fe2O3and V2O5

The Catalytic Performance of Ultrasonically Prepared AlPO4 Nanocatalysts for the Selective Production of Dimethyl Ether from Methanol

Thermal studies on cobalt(II), nickel(II) and copper(II) ternary complexes of N-(2-acetamido) iminodiacetic acid and imidazoles