scholarly journals Oxidative Dehydrogenation of Propane over Vanadium Catalyst Supported on Alkali-Modifiedx-Al2O3

2021 ◽  
pp. 1-15
Author(s):  
Vinicius M. Crivelaro ◽  
Sayuri Okamoto ◽  
Gilberto G. Cortez
Keyword(s):  
Oxidative Dehydrogenation ◽  
Alkali Metals ◽  
Large Fraction ◽  
Molar Fraction ◽  
Propane Conversion ◽  
Promoting Effect ◽  
Alumina Support ◽  
Molar Ratios ◽  
Propane Odh ◽  
Acidic Sites

The propane oxidative dehydrogenation (ODH) reaction has been considered as an alternative method for propene production owing to its exothermic nature, which renders it environmentally friendly. The use of alkaline promoters for supported V catalysts can increase propene selectivity and partially inhibit the formation of CO and CO2. Our goal was to evaluate the promoting effect of K and Na and the support effect using gibbsite as precursor for the propane ODH reaction. Catalysts were prepared via co-impregnation of V and alkali metals on a previously prepared alumina support and were characterized using N2 adsorption-desorption, X-ray diffraction, temperature-programmed reduction, and isopropanol decomposition tests to evaluate their acid-base properties. The activity of the synthesized catalysts for the propane ODH reaction was evaluated at the O2:C3H8:He molar ratios of 5:2:4, 6:1:4, and 4:3:4. The addition of alkali metals to the V catalysts increased propane conversion and propene selectivity; moreover, both parameters increased with increasing molar fraction of O2 in the reactants. K doping increased the propene selectivity of the doped catalysts, because it inhibited a large fraction of catalytic surface acidic sites. A high molar fraction of O2 in the reactants facilitated the regeneration of the catalyst, whereas a high reoxidation rate improved catalytic activity and propene selectivity.

Preparation, Characterization, and Oxidative Dehydrogenation of C3H8 with CO2 of V-Cr/SBA-15/Al2O3/FeCrAl Metal Monolithic Catalysts

2011 ◽  
Vol 287-290 ◽  
pp. 1671-1674 ◽  
Author(s):  
Hong Jiang Zhang ◽  
Zhi Gang Jia ◽  
Sheng Fu Ji
Keyword(s):  
Catalytic Activity ◽  
Oxidative Dehydrogenation ◽  
Mesoporous Structure ◽  
Propane Conversion ◽  
Monolithic Catalysts ◽  
Propylene Selectivity ◽  
Vanadium Species

A series of V-Cr/SBA-15/Al2O3/FeCrAlmetal monolithic catalystswithV content of 10wt% and Cr contents from 0 to 12.5wt% were prepared. The structure of the catalysts was characterized using XRD, XPS and TPR techniques. The catalytic activity for oxidative dehydrogenation (ODH) of propane with CO2was evaluated. The results indicate that the mesoporous structure of SBA-15 was retained after vanadium and chromium incorporation and the vanadium species were well dispersed. The V-Cr/SBA-15/Al2O3/FeCrAl catalyst with 10wt%V and 10 wt% Cr exhibited the best activity with a propane conversion of 49.9% and a propylene selectivity of 86.5% at 650 °C.

scholarly journals Higher propene yield by tailoring operating conditions of propane oxidative dehydrogenation over V2O5/γ-Al2O3

2015 ◽  
Vol 80 (3) ◽  
pp. 355-366 ◽  
Author(s):  
Yousef Zaynali ◽  
Seyed Alavi
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxidative Dehydrogenation ◽  
Atmospheric Pressure ◽  
Operating Conditions ◽  
Propane Conversion ◽  
Propane Oxidative Dehydrogenation ◽  
Wet Impregnation ◽  
Vanadia Catalyst ◽  
Oxygen Ratio

Supported vanadia catalyst was successfully synthesized using wet impregnation of ?-Alumina to study Propane Oxidative Dehydrogenation (POD). The prepared catalysts were characterized with XRD, BET, and TPR tests. In a broad temperature range (340 to 630?C), effects of vanadia loading (2.7, 5.4, and 9 wt%) and propane to oxygen ratio (3/1 to 1/3) were thoroughly investigated on propane conversion as well as propene yield at atmospheric pressure. Results indicate that by increasing the vanadia content the activity of catalyst increases while selectivity to propene decreases monotonically. As the temperature increases from 340?C to 630?C, yield to propene shows ascending behavior in case of all catalyst samples. Yield to propene shows a climax with changing propane to oxygen ratio from 3/1 to 1/3. The yield increases with increase in oxygen partial pressure of feed until equimolar ratio of propane and oxygen, then it declines with further increase of oxygen partial pressure. A maximum propene yield of 17% was experienced on catalyst with 2.7wt% vanadia at temperatures at 550?C.

scholarly journals Femtosecond Laser-Induced Formation of Gold-Rich Nanoalloys from the Aqueous Mixture of Gold-Silver Ions

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Yuliati Herbani ◽  
Takahiro Nakamura ◽  
Shunichi Sato
Keyword(s):  
Femtosecond Laser ◽  
Large Fraction ◽  
Molar Fraction ◽  
Silver Ions ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Transmission Electron ◽  
Direct Irradiation ◽  
Gold Silver ◽  
Aqueous Mixture

The synthesis of gold-silver (AuAg) nanoalloys of various compositions has been performed by direct irradiation of highly intense femtosecond laser pulse in the presence of polyvinylpyrrolidone (PVP). The mixture of Au and Ag ions of low concentration was simply introduced into a glass vial and subjected to femtosecond laser pulses for several minutes. The AuAg nanoalloys of 2-3 nm with reasonably narrow size distribution were formed, and the position of the surface plasmon resonance (SPR) increased monotonically with an increase in the gold molar fraction in the ion solutions. The high resolution transmission electron microscope (HRTEM) images exhibited the absence of core-shell structures, and the energy dispersive X-ray spectroscopy (EDX) analysis confirmed that the particles were Au-rich alloys even for the samples with large fraction of Ag+ions fed in the solution mixture. The formation mechanism of the alloy nanoparticles in the high intensity optical field was also discussed.

ChemInform Abstract: Synergistic Promoting Effect of Ball Milling and KF-Alumina Support for the Green Synthesis of Benzothiazinones.

ChemInform ◽  
2016 ◽  
Vol 47 (21) ◽  
Author(s):  
Ali Sharifi ◽  
Mohammad Ansari ◽  
Hossein Reza Darabi ◽  
M. Saeed Abaee
Keyword(s):  
Green Synthesis ◽  
Ball Milling ◽  
Promoting Effect ◽  
Alumina Support

scholarly journals Development of V-Based Oxygen Carriers for Chemical Looping Oxidative Dehydrogenation of Propane

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 119
Author(s):  
Tianwei Wu ◽  
Qingbo Yu ◽  
Kun Wang ◽  
Martin van Sint Annaland
Keyword(s):  
Oxidative Dehydrogenation ◽  
Oxygen Transport ◽  
Propane Conversion ◽  
Chemical Looping ◽  
Impregnation Method ◽  
Oxygen Carriers ◽  
Oxidative Dehydrogenation Of Propane ◽  
Transport Capacity ◽  
Mechanical Mixing ◽  
Oxygen Transport Capacity

Two different preparation methods, viz. incipient impregnation and mechanical mixing, have been used to prepare V-based oxygen carriers with different V loadings for chemical looping oxidative dehydrogenation of propane. The effect of the preparation method, V loading, and reaction temperature on the performance of these oxygen carriers have been measured and discussed. It was found that the VOx species can be well distributed on the support when the V loading is low (5 wt.% and 10 wt.%), but they may become aggregated at higher loadings. For oxygen carriers with a higher V loading, the oxygen transport capacity of the oxygen carrier, propane conversion and COx selectivities increase, while the propylene selectivity decreases. With a V-loading of 10 wt.%, the maximum propylene yield was achieved. The VOx species were better distributed over the support when applying the impregnation method; however, at higher V loadings the V-based oxygen carriers prepared by mechanical mixing showed a larger oxygen transport capacity. The oxygen carriers prepared by impregnation showed a better performance for the oxidative dehydrogenation of propane (ODHP) and re-oxidation reactions compared to oxygen carriers prepared by mechanical mixing. Higher reaction temperatures are favorable for the re-oxidation reaction, but unfavorable for the propylene production.

scholarly journals Acetonitrile Synthesis via Ammoxidation: Mo/zeolites Catalysts Screening

2020 ◽  
pp. 16-30
Author(s):  
Faouzi Ayari ◽  
Emna Mannei ◽  
Esther Asedegbega-Nieto ◽  
Mourad Mhamdi ◽  
Gérard Delahay
Keyword(s):  
Oxidative Dehydrogenation ◽  
The Other ◽  
Combustion Reaction ◽  
Hydrophobic Character ◽  
Molar Ratios ◽  
Solid Interface ◽  
Oxidative Treatment ◽  
Other Hand ◽  
Dispersion State ◽  
Dehydration Enthalpy

Mo/zeolites catalysts were investigated in ethane and ethylene ammoxidation into acetonitrile. The catalysts were prepared either in solid‒solid or liquid‒solid interface after varying different parameters. The stabilization of Mo species upon the exchange is dependent on the hydrophilic/hydrophobic character of the zeolite and the type of Mo precursor. In fact, zeolites with low Si/Al molar ratios should be avoided due to their higher dehydration enthalpy values (Δdehyd.H). On the other hand, the use of MoOCl4, Mo(CO)6 and MoCl3 precursors and zeolites with high Si/Al ratios led to inefficient [Mo7O24]6‒ species and amorphous MoO3 which catalyzes the combustion reaction. Nevertheless, the use of MoCl5, MoO3 and MoO2(C5H7O2)2 led to promising activities. In catalysis, [MoO4]2‒ species are required to activate C2H6 into C2H4, while [MoxO3x+1]2‒ (x =1, 2) species catalyze the ammoniation of C2H4 and the ethylamine dehydrogenation into CH3CN. Interestingly, active catalysts could be obtained by humid impregnation and a simultaneous oxidative treatment. Such a treatment improves the dispersion state of crystalline MoO3, which activate ethane molecules. It is judicious to perform C2H6 oxidative dehydrogenation before ammoxidation since the interference between the different investigated parameters could be noted.

scholarly journals Balancing the Activity and Selectivity of Propane Oxidative Dehydrogenation on NiOOH (001) and (010)

2020 ◽  
Vol 26 (5) ◽  
pp. 341-351
Author(s):  
Lisheng Li ◽  
Hua Wang ◽  
Jinyu Han ◽  
Xinli Zhu ◽  
Qingfeng Ge
Keyword(s):  
Oxidative Dehydrogenation ◽  
Density Functional ◽  
Activation Barrier ◽  
Propane Oxidative Dehydrogenation ◽  
Functional Theory ◽  
Activation Barriers ◽  
Propylene Oxidation ◽  
Propane Odh ◽  
High Activation Barrier ◽  
Allylic Radical

Abstract Propane oxidative dehydrogenation (ODH) is an energy-efficient approach to produce propylene. However, ODH suffers from low propylene selectivity due to a relatively higher activation barrier for propylene formation compared with that for further oxidation. In this work, calculations based on density functional theory were performed to map out the reaction pathways of propane ODH on the surfaces (001) and (010) of nickel oxide hydroxide (NiOOH). Results show that propane is physisorbed on both surfaces and produces propylene through a two-step radical dehydrogenation process. The relatively low activation barriers of propane dehydrogenation on the NiOOH surfaces make the NiOOH-based catalysts promising for propane ODH. By contrast, the weak interaction between the allylic radical and the surface leads to a high activation barrier for further propylene oxidation. These results suggest that the catalysts based on NiOOH can be active and selective for the ODH of propane toward propylene.

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