Structural characteristics of selected metal oxides used for the catalytic pyrolysis of sunflower oil

2015 ◽  
Vol 114 ◽  
pp. 60-67 ◽  
Author(s):  
Zerihun Demrew Yigezu ◽  
Karuppan Muthukumar
Keyword(s):  
Metal Oxides ◽  
Sunflower Oil ◽  
Catalytic Pyrolysis ◽  
Structural Characteristics

scholarly journals Mathematical modeling of perspective structures of metal oxides

2020 ◽  
Vol 22 (4) ◽  
pp. 268-271
Author(s):  
P. A. Sechenykh
Keyword(s):  
Metal Oxides ◽  
Crystal Lattice ◽  
Structural Characteristics ◽  
Elementary Cell ◽  
Group Symmetry ◽  
Cubic Symmetry ◽  
Lattice Constants ◽  
General Chemical ◽  
Crystalline Metal ◽  
Chemical Formulas

Information about the structure and properties of materials is especially important when working with micro-and nanoscale objects due to the high complexity of their obtaining. This makes it relevant to use computer modeling to predict the required characteristics of materials. Electronic, magnetic, mechanical, and other properties of crystalline substances are determined by their structure-the periodicity of the lattice and the symmetry of the unit cell. This article discusses metal oxides with the general chemical formulas MeO (metals: Ca, Cd, Mg), MeO2 (metals: Hf, Ce, Zr), Me2O3 (metals: Er, Nd, Sc, Mn, Tl) and Me3O4 (using Fe as an example) and a cubic symmetry type crystal lattice — structural types NaCl (rock salt), Fluorite, Bixbyite, Spinel accordingly. The paper describes the model of ion-atomic radii, which is widely used in the modeling of crystalline metal oxides. The application of the annealing simulation algorithm for calculating the metric parameters of the compounds under consideration is shown. The software implementation of the algorithm presented in this paper allows us to determine the coordinates of the atoms that are included in the elementary cell of the crystal lattice, calculate the lattice constant and the density of the packing of atoms in the crystal cell using the specified chemical formula and the space group symmetry. These structural characteristics can be used as input parameters for determining electronic, magnetic, and other properties. The article compares the values of lattice constants obtained as a result of modeling with experimental data.

Aromatics production with metal oxides and ZSM-5 as catalysts in catalytic pyrolysis of wood sawdust

2019 ◽  
Vol 188 ◽  
pp. 146-152 ◽  
Author(s):  
Qingfeng Che ◽  
Minjiao Yang ◽  
Xianhua Wang ◽  
Xu Chen ◽  
Wei Chen ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Catalytic Pyrolysis ◽  
Wood Sawdust

Catalytic pyrolysis of polyethylene waste with Fuller’s earth clay and metal oxides under mild conditions

2022 ◽  
Author(s):  
Muhammad Shozab Mehdi ◽  
Muhammad Taqi Mehran ◽  
Salman Raza Naqvi ◽  
Shafiq Uz Zaman ◽  
Asif Hussain Khoja ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Catalytic Pyrolysis ◽  
Mild Conditions ◽  
Fuller’S Earth

scholarly journals Comparisons of metal oxides activity in the transesterification of triglycerides by С1–С4 alcohols

2020 ◽  
pp. 99-105
Keyword(s):  
Metal Oxides ◽  
Sunflower Oil ◽  
Manganese Oxides ◽  
Reaction Rate ◽  
Aliphatic Alcohols ◽  
Transesterification Reaction ◽  
Molar Ratio ◽  
Initial Reaction ◽  
High Catalytic Activity ◽  
Reaction Duration

The activity of heterogeneous catalysts for the transesterification reaction of sunflower oil triglycerides with aliphatic alcohols of normal structure was investigated in this work. Fine-dispersed oxides ZnO, NiO, FeO, CuO and MnO served as catalysts. The following aliphatic alcohols were used in the transesterification process of sunflower oil triglycerides: methanol, ethanol, propan-1-ol and butan-1-ol. The transesterification reaction was performed under the conditions as follows: the content catalyst of 0.25 wt.%, the triglycerides:alcohol molar ratio of 6.5:1 and the temperature of 333 K (methanol) or 348 K (ethanol, propan-1-ol and butan-1-ol). The investigated metal oxides were arranged in series according to their activity towards the transesterification reaction of sunflower oil triglycerides with C1–C3 alcohols. It was established that these series were practically the same for the mentioned alcohols. Similarity between the oil conversion curves of the reaction duration for C1–C3 aliphatic alcohols in the presence of all studied catalysts was shown. The use of the most active catalysts (ZnO and NiO) for the transesterification reaction of triglycerides with C1–C3 aliphatic alcohols allowed achieving the triglycerides conversion of more than 95% at the reaction duration of 2.5 h. Iron and manganese oxides exhibited relatively high catalytic activity in the transesterification reaction with aliphatic C1–C2 alcohols. However, the oil conversion was only 86.7–91.1% for the transesterification reaction by propan-1-ol in the presence of above-mentioned catalysts under the optimal conditions (reaction duration of 2.5 h). Copper oxide exhibited the lowest activity among all catalysts that were tested. The highest initial reaction rate in the presence of metal oxides was achieved in the transesterification of sunflower oil triglycerides by methanol. The reaction rate of triglycerides transesterification by butan-1-ol was by three orders of magnitude lower than that achieved by using of other alcohols.

scholarly journals Technological Aspects of Vegetable Oils Transesterification with Ethanol in the Presence of Metal Oxides

2020 ◽  
Vol 69 (7-8) ◽  
pp. 365-370
Author(s):  
Yuriy Melnyk ◽  
Roman Starchevskyi ◽  
Stepan Melnyk
Keyword(s):  
Zinc Oxide ◽  
Catalytic Activity ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Vegetable Oil ◽  
Vegetable Oils ◽  
Sunflower Oil ◽  
Mass Fraction ◽  
Oxide Catalyst ◽  
Oxide Particles

Transesterification of vegetable oil with ethanol in the presence of fine metal oxide particles as catalysts has been investigated. Zinc and nickel(II) oxides were shown to have the highest catalytic activity. In their presence, the conversion of sunflower oil triglycerides, after 150 min, reached 95.3 and 94.2 %, respectively. The optimal mass fraction of zinc oxide catalyst was found to be 0.25–0.31 %. In the presence of zinc oxide, with mass fraction of water in ethanol of 5 and 10 %, the conversion of triglycerides was 98.5 and 94.8 %, respectively.

scholarly journals EFFECT OF PHYSICOCHEMICAL PROPERTIES OF d-METAL OXIDES ON SUNFLOWER OIL TRANSESTERIFICATION

2021 ◽  
pp. 113-120
Author(s):  
Yurii Melnyk ◽  
Stepan Melnyk ◽  
Halyna Mahorivska ◽  
Viktor Reutskyy
Keyword(s):  
Specific Surface ◽  
Metal Oxides ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sunflower Oil ◽  
Aqueous Suspension ◽  
Surface Acidity ◽  
Weak Acid ◽  
Transesterification Reaction ◽  
Acidity And Basicity

The physicochemical indicators of d-metal oxides (NiO, CuO, MnO, FeO, PbO, ZnO) which are heterogeneous catalysts for the transesterification process of sunflower oil triglycerides by ethanol and butan-1-ol have been determined. The available specific surface area, surface acidity and basicity, as well as the hydrogen potential change of the catalyst suspension in water were determined for the oxides. The available specific surface area of the oxides was determined by titration of their aqueous suspension with a solution of methylene blue with a predetermined concentration. The surface acidity and basicity of the catalysts were determined by back titration of samples treated with an aqueous solution of ammonia and acetic acid, respectively. It was found that all investigated d-metal oxides have a low specific surface area. The value of specific surface area is in the range of 0.6-1.5 m2/g. The surface acidity and basicity of the catalysts is 0.13-0.27 mmol/g and 0.019-0.066 mmol/g, respectively. It is shown that the change in the aqueous suspension hydrogen potential of the investigated catalysts relative to the distilled water pH is maximum for NiO and ZnO and it is 0.6-0.65, while for CuO this change is the smallest and it is only 0.3. The character of the pH change curves and the pH values of the oxides suspension in equilibrium condition indicate the presence of weak acid sites in the studied catalysts. The indicated catalysts characteristics are compared with the results obtained in the transesterification process of sunflower oil triglycerides by ethanol and butan-1-ol. It was found that there is a correlation between the surface acidity of catalyst and the reaction initial rate of triglycerides transesterification by ethanol and butan-1-ol. At the same time, such a correlation is absent for the surface basicity of the catalysts. This is consistent with the data on the catalysis of the triglyceride transesterification reaction only by strong major active sites. It is concluded that the transesterification reaction of sunflower oil triglycerides by ethanol and butan-1-ol occurs predominantly on the weak acid centers of the d-metal oxides.

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