Nickel and cobalt phosphides as effective catalysts for oxygen removal of dibenzofuran: role of contact time, hydrogen pressure and hydrogen/feed molar ratio

2015 ◽  
Vol 5 (6) ◽  
pp. 3403-3415 ◽  
Author(s):  
A. Infantes-Molina ◽  
E. Gralberg ◽  
J. A. Cecilia ◽  
Elisabetta Finocchio ◽  
E. Rodríguez-Castellón
Keyword(s):  
Catalytic Activity ◽  
Contact Time ◽  
Hydrogen Pressure ◽  
Oxygen Removal ◽  
Molar Ratio ◽  
Metal Loading ◽  
Molar Ratios ◽  
Feed Molar Ratio

The catalytic activity of nickel and cobalt phosphides, with a metal loading of 5 wt.%, supported on silica was investigated in the hydrodeoxygenation reaction (HDO) of dibenzofuran (DBF) as a model oxygenated compound at different contact times, H2 pressures and H2/DBF molar ratios.

Appearance, corrosion properties, and leach resistance of spruce and pine wood treated with Mea modified micronized copper preservative (MCu)

Holzforschung ◽  
2014 ◽  
Vol 68 (4) ◽  
pp. 477-486 ◽  
Author(s):  
Myung Jae Lee ◽  
Sedric Pankras ◽  
Paul Cooper
Keyword(s):  
Wood Species ◽  
Wood Preservative ◽  
Molar Ratio ◽  
Corrosion Properties ◽  
Pine Wood ◽  
Molar Ratios ◽  
Copper Leaching ◽  
Mold Resistance ◽  
Refractory Wood

Abstract Canadian refractory wood species treated with micronized copper (MCu) wood preservative become mottled and streaky in appearance. To overcome this issue, the MCu system was modified by adding small amounts of monoethanolamine (Mea). The modified systems were evaluated to clarify the role of Mea in terms of leaching, corrosion, and mold resistance of MCu systems. The mottled and streaky surface on treated spruce was prevented at Mea/Cu molar ratios between 0.7 and 1.5. Copper leaching remained modest and was only slightly higher than that of MCu alone up to a Mea/Cu molar ratio of 1.2. However, adding even a small amount of Mea to the MCu formulation increased fastener corrosion compared with MCu. Protonated Mea increased as more Mea was added and was identified as the main corrosion-causing electrolyte in the system.

scholarly journals A green approach to the synthesis of a nano catalyst and the role of basicity, calcination, catalytic activity and aging in the green synthesis of 2-aryl bezimidazoles, benzothiazoles and benzoxazoles

RSC Advances ◽  
2017 ◽  
Vol 7 (67) ◽  
pp. 42000-42012 ◽  
Author(s):  
Pramod K. Sahu
Keyword(s):  
Catalytic Activity ◽  
Green Synthesis ◽  
Room Temperature ◽  
Molar Ratios ◽  
Green Approach ◽  
Grinding Method ◽  
Nano Catalyst ◽  
Layered Catalyst

A green synthesis of hydrotalcite (a double layered catalyst) by a grinding method using Al/Mg molar ratios of 1.0–3.0 at room temperature is described.

The Control of the Reactions of Strontium Hexaferrite Formation by the Molar Ratio of Precursors

2007 ◽  
Vol 280-283 ◽  
pp. 471-472
Author(s):  
S.A. Seyyed Ebrahimi
Keyword(s):  
Critical Parameters ◽  
Molar Ratio ◽  
Strontium Hexaferrite ◽  
Strontium Oxide ◽  
Molar Ratios ◽  
Temperature Method ◽  
Wide Range ◽  
Method Of Production ◽  
Thermal Analysis Techniques

Strontium hexaferrite is one of the very important categories of magnetic materials with a wide range applications. One of the very critical parameters in the high temperature method of production of this material is molar ratio of iron oxide to strontium oxide. Although there could be found some reports on the effect of this parameter on the physical properties of the material in the literature but there are very few investigations about the role of this factor on the reactions occurred in the process. In this work the effect of different molar ratios of precursors on the reactions carried out for processing of strontium hexaferrite have been investigated by using thermal analysis techniques such as DTA/TG. Furthermore, the microstructure and the powder and bulk magnetic properties of the products have been studied by SEM, VSM and permeameter.

Role of calcium ions and phospholipids in platelet aggregation and plug formation

1965 ◽  
Vol 209 (6) ◽  
pp. 1128-1136 ◽  
Author(s):  
Melvin J. Silver
Keyword(s):  
Thrombus Formation ◽  
Divalent Cations ◽  
Adenosine Diphosphate ◽  
Molar Ratio ◽  
Triggering Mechanism ◽  
Molar Ratios ◽  
Phospholipid Micelles ◽  
Plug Formation ◽  
Aggregation Of Platelets

Certain phospholipids aggregate and form "plugs" in a simple system in which all variables are easily controlled. Aggregation requires the presence of divalent cations. Suspensions of lecithin are totally inactive whereas those of phosphatidylethanolamine and interaction products of lecithin and phosphatidylserine (molar ratio 1/1) aggregate and form plugs. Phosphatidylserine and lecithin-phosphatidylserine interaction products at higher molar ratios produce some aggregation but do not form plugs. Adenosine diphosphate (in the presence of small amounts of calcium) can accelerate the formation of small aggregates of platelets or exogenous phospholipids, but cannot bring about the formation of large aggregates or plugs. The hypothesis is presented that aggregation of platelets in physiological thrombus formation occurs after a triggering mechanism "uncovers" phospholipid micelles in platelets. The newly available negative charges on the polar ends of phospholipids would then be bridged by divalent cations present in the surrounding plasma, producing aggregates and plugs.

Study on CO2 Hydrogenation to Light Olefins on Iron Catalysts

2011 ◽  
Vol 347-353 ◽  
pp. 808-811 ◽  
Author(s):  
Cheng Xue Wang ◽  
Xiang Bo Wang
Keyword(s):  
Catalytic Activity ◽  
Calcination Temperature ◽  
Reaction Temperature ◽  
Space Velocity ◽  
Light Olefins ◽  
Iron Catalysts ◽  
Molar Ratio ◽  
Factors Of Influence ◽  
Xrd And Tem

Fe-Cu-K2O-La2O3catalysts were prepared by special impregnation on the SiO2, ZrO2and SiO2-ZrO2. Some factors of influence on catalytic activity were researched,such as the content of active component Cu and La, calcination temperature, reaction temperature and space velocity. The structures and physicochemical properties of the catalysts were characterized by XRD and TEM. When the SiO2-ZrO2play the role of carrier , Fe:Cu:K:La = 100:15:7:7:250:250, the calcination temperature is 773K, the reaction temperature is 613K and space velocity is 2400ml • h-1• g-1(cat), the catalyst shows the best catalytic activity , if the reaction pressure is 0.1 Mpa , and the molar ratio of H2to CO2is 3 . The conversion of CO2is more than 64%. Light olefin’s selectivity is more than 25%.

scholarly journals The Role of Silica in the Chlorination–Volatilization of Cobalt Oxide by Using Calcium Chloride

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2036
Author(s):  
Peiwei Han ◽  
Zhengchen Li ◽  
Xiang Liu ◽  
Jingmin Yan ◽  
Shufeng Ye
Keyword(s):  
Cobalt Oxide ◽  
Calcium Chloride ◽  
Molar Ratio ◽  
Molar Ratios

The role of silica in the chlorination–volatilization of cobalt oxide, using calcium chloride, is investigated in this paper. It is found that the Co volatilization percentage of the CoO–Fe2O3–CaCl2 system is not larger than 12.1%. Silica plays an important role in the chlorination–volatilization of cobalt oxide by using calcium chloride. In the CoO–SiO2–Fe2O3–CaCl2 system, the Co volatilization percentage is initially positively related to the molar ratio of SiO2 to CaCl2, and remains almost constant when the molar ratio of SiO2 to CaCl2 rises from zero to eight. The critical molar ratios of SiO2 to CaCl2 are 1 and 2 when the molar ratios of CaCl2 to CoO are 8.3 and 16.6, respectively. The Co volatilization percentage remains almost constant with the increase in CaO concentration, and decreases when Al2O3 and MgO are added. Ca2SiO3Cl2 is determined after roasting at 1073 K and 1173 K, and disappears at temperatures in excess of 1273 K in the calcines from the CoO–SiO2–CaCl2 system. CaSiO3 always exists in the calcines at temperatures in excess of 973 K.

THE CATALYTIC ROLE OF BIRNESSITE IN THE TRANSFORMATION OF IRON

1987 ◽  
Vol 67 (3) ◽  
pp. 533-543 ◽  
Author(s):  
G. S. R. KRISHNAMURTI ◽  
P. M. HUANG
Keyword(s):  
Key Words ◽  
Infrared Absorption ◽  
Molar Ratio ◽  
Acidic Ph ◽  
Chemical Analyses ◽  
X Ray ◽  
Molar Ratios ◽  
Fe Oxides ◽  
Catalytic Role

The influence of birnessite (δ-MnO2) on the precipitation products of iron was studied, in the FeCl2-NH4OH system at different Mn/Fe molar ratios (0, 0.01, 0.1 and 1.0) and in the acidic pH (4.0, 5.0 and 6.0) range, by X-ray, TEM, IR and chemical analyses. The precipitation products formed at pH 5.0 and 6.0 were found to be lepidocrocite (γ-FeOOH) in the absence of birnessite. Birnessite promoted increased precipitation of Fe oxide; the oxidation of Fe(II) by MnO2 was thermodynamically feasible and was confirmed by the presence of Mn(II) in the solution by ESR data. Birnessite also influenced the crystallization processes of hydrolytic products of Fe which range from lepidocrocite through goethite (α-FeOOH), akaganeite (β-FeOOH), to X-ray noncrystalline Fe oxides. The noncrystalline Fe oxides formed at a Mn/Fe molar ratio of 1.0 were characterized by infrared absorption maxima at 1400 and 750 cm−1. Key words: Birnessite, Fe(II) oxidation, ESR, lepidocrocite, akaganeite, noncrystalline oxide

Catalytic activity of rhodium(I) complexes containing poly(siloxy)alkyldiphenylphosphines

1980 ◽  
Vol 45 (7) ◽  
pp. 2100-2107 ◽  
Author(s):  
Vladimír Kavan ◽  
Martin Čapka
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Pressure ◽  
Catalyst Activity ◽  
Molar Ratio ◽  
Normal Hydrogen ◽  
Kinetics Of

Kinetics of homogenous hydrogenation of 1-heptene catalysed by rhodium(I) complexes prepared in situ from di-μ.μ'-chloro-bis(dicyclooctenerhodium) and phosphine L (L = 2-(diethoxymethylsilyl)ethyldiphenylphosphine, 3-(diethoxymethylsilyl)propyldiphenylphosphine and their copolymers with diethoxydimethylsilane) have been studied at 64°C under normal hydrogen pressure. The dependence of the catalyst activity on the type of L( monomeric, polymeric, supported on silica) has been examined. The effects of Rh : P molar ratio, the concentration of phosphine groups in siloxane copolymers and of the method of catalyst fixation to support on catalyst performance are discussed.

scholarly journals Facile fabrication, characterization and catalytic activity of a NiMo/Al2O3 nanocatalyst via a solution combustion method used in a low temperature hydrodesulfurization process: the effect of fuel to oxidant ratio

RSC Advances ◽  
2020 ◽  
Vol 10 (21) ◽  
pp. 12439-12450
Author(s):  
Roya Hamidi ◽  
Reza Khoshbin ◽  
Ramin Karimzadeh
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Combustion Method ◽  
Solution Combustion ◽  
Solution Combustion Method ◽  
Molar Ratios ◽  
Facile Fabrication ◽  
Hydrodesulfurization Process ◽  
Hydrodesulfurization Activity

Novel bimetallic NiMo/Al2O3 nanocatalysts were fabricated via a solution combustion method to evaluate the role of fuel to oxidant molar ratios on their structural properties and hydrodesulfurization activity.

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