scholarly journals Transformation of 2-Butene into Propene on WO3/MCM-48: Metathesis and Isomerization of n-Butene

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 585 ◽  
Author(s):  
Derun Hua ◽  
Zheng Zhou ◽  
Qianqian Hua ◽  
Jian Li ◽  
Xinning Lu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Temperatures ◽  
Thermodynamic Analysis ◽  
Reaction Temperature ◽  
Thermodynamic Calculations ◽  
Metathesis Reaction ◽  
Good Catalytic Activity

The metathesis of 2-butene (Trans and Cis) to propene was investigated over W-based catalysts. Thermodynamic calculations for metathesis and isomerization were carried out at various temperatures to test the reactions. The results showed that the WO3/MCM-48 catalyst had good catalytic activity. The metathesis activity depended on the acidity of the catalyst and the dispersity of the WO3 on the supports. High temperatures promoted the isomerization of 2-butene to 1-butene. According to thermodynamic analysis, however, this is adverse to the metathesis reaction, making it important to determine an appropriate reaction temperature.

Catalytic Decomposition of Methane: Effect of Various Factors on Catalytic Properties

2007 ◽  
Vol 544-545 ◽  
pp. 23-26 ◽  
Author(s):  
Hyun Chang Shin ◽  
Hyun Jung Kim ◽  
Dong Shin Yun ◽  
Jung Whan Yoo ◽  
Dong Jin Lee ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Temperature ◽  
Methane Conversion ◽  
Catalytic Properties ◽  
Catalytic Decomposition ◽  
Good Catalytic Activity ◽  
Decomposition Of Methane ◽  
Mesoporous Supports ◽  
Mcm 41

The effect of various reaction factors such as amount of Ni loaded, temperature, and variety of supports on the methane conversion were investigated to obtain higher methane conversion. The high activities were observed over Ni(10 wt%)/SiO2 catalyst and at 650oC of reaction temperature. Catalysts using mesoporous supports such as SiO2 and MCM-41 showed good catalytic activity and stability.

High resolution electron microscopy of lanthanum phosphate crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 274-275
Author(s):  
J. C. Wheatley ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
High Resolution ◽  
Petroleum Industry ◽  
High Resolution Electron Microscopy ◽  
Lanthanum Phosphate ◽  
Good Catalyst ◽  
Resolution Electron ◽  
Good Catalytic Activity ◽  
Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

scholarly journals CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 131 ◽  
Author(s):  
Rola Mohammad Al Soubaihi ◽  
Khaled Mohammad Saoud ◽  
Myo Tay Zar Myint ◽  
Mats A. Göthelid ◽  
Joydeep Dutta
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Active Sites ◽  
Bond Activation ◽  
Dissociative Adsorption ◽  
High Catalytic Activity ◽  
Good Catalytic Activity ◽  
Pretreatment Conditions ◽  
Oxidation Efficiency

Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (Tig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than Tig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at Tig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition.

scholarly journals Palladium-Supported Zirconia-Based Catalytic Degradation of Rhodamine-B Dye from Wastewater

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1522
Author(s):  
Salma Jabeen ◽  
Muhammad Sufaid Khan ◽  
Rozina Khattak ◽  
Ivar Zekker ◽  
Juris Burlakovs ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Rhodamine B ◽  
Dye Degradation ◽  
Freundlich Isotherm ◽  
Impregnation Method ◽  
K Value ◽  
First Order Kinetics ◽  
Good Catalytic Activity ◽  
Rhodamine B Dye ◽  
Best Fit

The catalytic activity of Pd/ZrO2 was studied in terms of the degradation of rhodamine-B dye in the presence of hydrogen peroxide. Pd/ZrO2 was prepared by impregnation method, calcined at 750 °C and characterized by XRD, SEM and EDX. The catalyst showed good catalytic activity for dye degradation at 333 K, using 0.05 g of the catalyst during 5 h. The reaction kinetics followed the pseudo-first order kinetics. The Freundlich, Langmuir and Temkin isotherms were applied to the data and the best fit was obtained with Freundlich isotherm. Thermodynamic parameters, like ΔH, ΔG and ΔS were also calculated. The negative values of ΔH (−291.406 KJ/mol) and Gibbs free energy (ΔG) showed the exothermic and spontaneous nature of the process. The positive ΔS (0.04832 KJ/mol K) value showed suitable affinity of catalyst for dye degradation. The catalyst was very stable, active and was easily separated from the reaction mixture by filtration. It can be concluded from the results that the prepared catalyst could be effectively used in dyes degradation/removal from water subjected to further validation and use for various dyes.

Synthesis, Characterization, and Crystal Structure of Several Novel Acidic Ionic Liquids: 1-ethyl-2-alkyl-benzimidazolium Tetra-Fluoroborate

2013 ◽  
Vol 457-458 ◽  
pp. 139-143 ◽  
Author(s):  
Ming Tian Wang ◽  
Chang Ping Pan ◽  
Wei Peng Gai ◽  
Xiao Xia Lv ◽  
Min Gang Zhai ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ionic Liquid ◽  
Acetic Acid ◽  
Catalytic Activity ◽  
Lamellar Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acidic Ionic Liquid ◽  
Acidic Ionic Liquids ◽  
Good Catalytic Activity

A series of novel acidic ionic liquid: 1-ethyl-2-alkyl-benzimidazolium tetra-fluoroborate (alkyl= Et, Pr-n, Bu-n) were prepared by simple acid-based neutralization of 1-ethyl-2-alkyl-benzimidazole and tetrafluoroboric acid. The compounds were characterized by FTIR spectra, elemental analysis,1HNMR spectra and thermogravimetric analysis. These novel tetra-fluoroborate salts show good catalytic activity to esterification of benzyl alcohol and acetic acid. Furthermore, a crystal of ([H-ebBiBF4) was prepared with the crystal structure and determined by X-ray diffraction analysis. The molecular is of lamellar structure as mainly π electron ring is stacked interleaving between two layers. The results of cation and anion arranged orderly in pair indicate that the coulombic attraction is more dominant. Simultaneously, the weak local hydrogen bonds C-H···F exist in the molecules.

scholarly journals Catalytic Degradation of Chitosan by Supported Heteropoly Acids in Heterogeneous Systems

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Hang Zhang ◽  
Zhipeng Ma ◽  
Yunpeng Min ◽  
Huiru Wang ◽  
Ru Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Catalytic Activity ◽  
Activated Carbon ◽  
Reaction Time ◽  
High Molecular Weight ◽  
Reaction Temperature ◽  
Water Soluble ◽  
High Catalytic Activity ◽  
High Molecular Weight Chitosan

Several kinds of composite materials with phosphotungstic acid (PTA) as the catalyst were prepared with activated carbon as support, and their structures were characterized. According to the Box–Behnken central combination principle, the mathematical model of the heterogeneous system is established. Based on the single-factor experiments, the reaction temperature, the reaction time, the amount of hydrogen peroxide and the loading capacity of PTA were selected as the influencing factors to study the catalyzed oxidation of hydrogen peroxide and degradation of high molecular weight chitosan. The results of IR showed that the catalyst had a Keggin structure. The results of the mercury intrusion test showed that the pore structure of the supported PTA catalyst did not change significantly, and with the increase of PTA loading, the porosity and pore volume decreased regularly, which indicated that PTA molecules had been absorbed and filled into the pore of activated carbon. The results of Response Surface Design (RSD) showed that the optimum reaction conditions of supported PTA catalysts for oxidative degradation of high molecular weight chitosan by hydrogen peroxide were as follows: reaction temperature was 70 ℃, reaction time was 3.0 h, the ratio of hydrogen peroxide to chitosan was 2.4 and the catalyst loading was 30%. Under these conditions, the yield and molecular weight of water-soluble chitosan were 62.8% and 1290 Da, respectively. The supported PTA catalyst maintained high catalytic activity after three reuses, which indicated that the supported PTA catalyst had excellent catalytic activity and stable performance compared with the PTA catalyst.

Efficient UV-vis-IR photothermocatalytic selective ethanol oxidation on MnOx/TiO2 nanocomposites significantly enhanced by a novel photoactivation

2020 ◽  
Vol 8 (3) ◽  
pp. 1254-1264 ◽  
Author(s):  
Yi Yang ◽  
Shaowen Wu ◽  
Yuanzhi Li ◽  
Qian Zhang ◽  
Xiujian Zhao
Keyword(s):  
Activation Energy ◽  
Catalytic Activity ◽  
Ethanol Oxidation ◽  
Good Catalytic Activity

MnOx/TiO2 nanocomposites exhibit good catalytic activity and excellent durability for photothermocatalytic selective ethanol oxidation under UV-vis-IR and IR irradiation. A novel photoactivation is found to significantly enhance catalytic activity due to activation energy being reduced upon irradiation.

New palladium(ii) complexes with 3-(2-pyridyl)-5-alkyl-1,2,4-triazole ligands as recyclable C–C coupling catalysts

2019 ◽  
Vol 43 (27) ◽  
pp. 10973-10984 ◽  
Author(s):  
Borys V. Zakharchenko ◽  
Dmytro M. Khomenko ◽  
Roman O. Doroshchuk ◽  
Ilona V. Raspertova ◽  
Viktoriia S. Starova ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Good Catalytic Activity

Compounds 4a–d revealed good catalytic activity and prospects for use as mesomorphic materials.

Pd/SiO2–AlPO4 systems. Influence of the preparation variables on their catalytic activity

1985 ◽  
Vol 63 (12) ◽  
pp. 3471-3477 ◽  
Author(s):  
A. Alba ◽  
M. A. Aramendia ◽  
V. Borau ◽  
C. Jimenez ◽  
J. M. Marinas
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Reaction Temperature ◽  
Hydrogen Pressure ◽  
Pd Catalysts ◽  
Metal Precursor ◽  
Preparation Conditions ◽  
Liquid Phase Hydrogenation ◽  
Initial Hydrogen Pressure ◽  
Catalyst Reduction

A study on the liquid phase hydrogenation of cyclohexene over a series of Pd catalysts supported on various SiO2–AlPO4 systems (using a concentration of 2.47 M, with methanol as solvent, the initial hydrogen pressure is 5 bar and reaction temperature 300 K) is reported in this paper. The reaction has been studied as a standard in order to determine the most suitable preparation conditions for these catalystsWe have also studied the influence of other factors such as the kind of support, the nature of the metal precursor, the previous calcination of the precursor, the addition of alkaline hydroxides, and the catalyst reduction with various agents, on the catalytic activity of different Pd-supported systems

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