scholarly journals Ethylene Extrusion Polymerization by Heterogeneous bi-Supported Ziegler-Natta Catalysts

2009 ◽  
Vol 3 (1) ◽  
pp. 67-72
Author(s):  
Mohammad Ali Semsarzadeh ◽  
◽  
Alireza Aghili ◽  
Keyword(s):  
Catalytic Activity ◽  
Atmospheric Pressure ◽  
Ethylene Polymerization ◽  
Santa Barbara ◽  
Catalytic Activities ◽  
Molar Ratios ◽  
Polymerization Reactor ◽  
Fibrous Morphology ◽  
Mcm 41 ◽  
Ziegler Natta Catalysts

The MCM-41 (Mobil Composition of Matter) and SBA-16 (Santa Barbara Amorphous) supported TiCl4 and TiCl4/MgCl2 catalysts with different molar ratios of Mg/Ti were synthesized and used for ethylene polymerization under atmospheric pressure. The nanochannels of these supports serve as a nanoscale polymerization reactor and the polyethylene nanofibers were extruded during the reaction. The effect of MgCl2 on catalytic activity and morphology of resulting polyethylene has been investigated too. MgCl2 has enhanced the catalytic activities and made the SBA-16/MgCl2/TiCl4 catalytic system has fibrous morphology.

Catalytic Activity of Dehydrogenation of Methanol to MF over Cu/MCM-41 and Cu-ZnO/MCM-41 Prepared by Impregnation and Grinding

2011 ◽  
Vol 396-398 ◽  
pp. 730-733
Author(s):  
Guo Ru Li ◽  
Gong Li ◽  
Shu Xi Zhou ◽  
Hui Juan Tong
Keyword(s):  
Catalytic Activity ◽  
Atmospheric Pressure ◽  
Molecular Sieves ◽  
Conversion Rate ◽  
Methyl Formate ◽  
Methanol Conversion ◽  
N2 Adsorption ◽  
Flow Microreactor ◽  
Adsorption Desorption ◽  
Mcm 41

Abstract. Using MCM-41 molecular sieves as the support, Cu-ZnO/MCM-41 and Cu/MCM-41 catalysts were prepared by impregnation and grinding. The catalysts were characterized by XRD, N2 adsorption-desorption and TPR methods. The catalytic activity of the dehydrogenation of methanol to methyl formate (MF) was evaluated using the flow microreactor under atmospheric pressure. According to the results, the catalyst prepared by impregnation had a better selectivity for the MF, but a lower methanol conversion rate. However, the product's selectivity could be improved by adding ZnO additive while the methanol conversion rate was reduced. For Cu/MCM-41 prepared by impregnation and grinding, the methanol conversion rate was 20.18% and 24.13% respectively at 250°C and the MF selectivity was 73.75% and 67.35% respectively. Likewise for Cu-ZnO/MCM-41 prepared by impregnation and grinding, the methanol conversion rate was 15.28% and 18.83% respectively at 250°C and the MF selectivity was 81.31% and 75.32% respectively.

scholarly journals Synthesis and Catalytic Performances of a Novel Zn-MOF Catalyst Bearing Nickel Chelating Diimine Carboxylate Ligands for Ethylene Oligomerization

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Suyan Liu ◽  
Ying Zhang ◽  
Quan Huo ◽  
Sasa He ◽  
Yang Han
Keyword(s):  
Catalytic Activity ◽  
Atmospheric Pressure ◽  
Treatment Method ◽  
Ethylene Oligomerization ◽  
Low Carbon ◽  
Catalytic Activities ◽  
Diimine Ligands ◽  
Temperature And Pressure ◽  
Ethylene Polymer ◽  
Catalytic Performances

A novel Zn-MOF[Zn3(OH)2L2] was synthesized from dicarboxylate ligands with diimine groups (1,4-bis(4-CO2HC6H4)-2,3-dimethyl-1,4-diazabutadiene). The physicochemical properties of the material were characterized by a series of technologies including XRD, SEM, and ICP. In order to adapt to the ethylene oligomerization process, a catalyst[Zn3OH2L1Ni2](denoted as Cat.A) possessing active Ni2+centers was prepared by a postsynthetic treatment method using dichloride nickel as a nickel source in this work. For comparison,α-diimine ligands with/without dicarboxylic acid groups reacted with dichloride nickel to obtain homogenous Cat.B and Cat.C, respectively. The effects of reaction parameters, includingn(Al)/n(Ni), temperature, and pressure on the oligomerization activities and oligomers distribution were investigated. The results demonstrated that all of catalysts used with diethylaluminum chloride were active for the ethylene oligomerization. Among them, Cat.A and Cat.B showed higher catalytic activities and higher selectivities to low-carbonα-olefins at atmospheric pressure. The Cat.A exhibited the optimal catalytic activity [6.7 × 105 g/(mol·Ni·h·atm)] for C4 (91.8%) under the conditions of Al/Ni = 1500,P= 1.0 atm, T = 20°C. In addition, Cat.A and Cat.B presented large amount of ethylene polymer, while Cat.C had a higher catalytic activity of ethylene oligomerization at high pressure.

Amorphous Alloy Ni-Fe-B: Preparation, Characterization and its Catalytic Ability for Hydrogen Generation

2014 ◽  
Vol 672-674 ◽  
pp. 592-596 ◽  
Author(s):  
Jun Zhang ◽  
Hai Rui Yao ◽  
Hua Bo Li ◽  
Xiao Kang Bai ◽  
Jing Jing Li
Keyword(s):  
Catalytic Activity ◽  
Amorphous Alloys ◽  
Reduction Method ◽  
Hydrogen Generation ◽  
Hydrogen Release ◽  
Catalytic Activities ◽  
Molar Ratios ◽  
Phase Reduction ◽  
Different Temperatures ◽  
Xrd And Tem

Several amorphous alloys (Ni-Fe-B) were synthesized using liquid phase reduction method. The influences of molar ratiosn(Fe)/n(Fe+Ni) and different temperatures on phase composition, morphology and catalytic activity were investigated. The resulting products were characterized by XRD and TEM methods, and the catalytic activities were also evaluated by way of hydrogen release ability of NaBH4hydrolysis. The results show that the products have stable amorphous phase structures. With the increase ofn(Fe)/n(Fe+Ni), the crystallizing tendency rises and the agglomeration strengthens. Under the conditions (T=333K,n(Fe)/n(Fe+Ni)=0.5), the as-prepared samples exhibit the highest catalytic activity, and the highest hydrogen generation rate is 1.70 mL/min-1.

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

scholarly journals Development of palladium catalysts modified by ruthenium and molybdenum as anode in direct ethanol fuel cell

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yonis Fornazier Filho ◽  
Ana Caroliny Carvalho da Cruz ◽  
Rolando Pedicini ◽  
José Ricardo Cezar Salgado ◽  
Priscilla Paiva Luz ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Palladium Catalysts ◽  
Carbon Support ◽  
X Ray Diffraction ◽  
Direct Ethanol Fuel Cell ◽  
Pd Catalysts ◽  
Bifunctional Mechanism ◽  
Catalytic Activities ◽  
Intrinsic Mechanism ◽  
Ternary Catalysts

AbstractPhysical and electrochemical properties of Pd catalysts combined with Ru and Mo on carbon support were investigated. To this end, Pd, Pd1.3Ru1.0, Pd3.2Ru1.3Mo1.0 and Pd1.5Ru0.8Mo1.0 were synthesized on Carbon Vulcan XC72 support by the method of thermal decomposition of polymeric precursors and then physically and electrochemically characterized. The highest reaction yields are obtained for Pd3.2Ru1.3Mo1.0/C and Pd1.5Ru0.8Mo1.0/C and, as demonstrated by thermal analysis, they also show the smallest metal/carbon ratio compared the other catalysts. XRD (X-ray Diffraction) and Raman analyses show the presence of PdO and RuO2 for the Pd/C and the Pd1.3Ru1.0/C catalysts, respectively, a fact not observed for the Pd3.2Ru1.3 Mo1.0 /C and the Pd1.5Ru0.8Mo1.0/C catalysts. The catalytic activities were tested for the ethanol oxidation in alkaline medium. Cyclic voltammetry (CV) shows Pd1.3Ru1.0/C exhibiting the highest peak of current density, followed by Pd3.2Ru1.3Mo1.0/C, Pd1.5Ru0.8Mo1.0/C and Pd/C. From, chronoamperometry (CA), it is possible to observe the lowest rate of poisoning for the Pd1.3Ru1.0/C, followed by Pd3.2Ru1.3Mo1.0/C, Pd1.5Ru0.8Mo1.0/C and Pd/C. These results suggested that catalytic activity of the binary and the ternary catalysts are improved in comparison with Pd/C. The presence of RuO2 activated the bifunctional mechanism and improved the catalytic activity in the Pd1.3Ru1.0/C catalyst. The addition of Mo in the catalysts enhanced the catalytic activity by the intrinsic mechanism, suggesting a synergistic effect between metals. In summary, we suggest that it is possible to synthesize ternary PdRuMo catalysts supported on Carbon Vulcan XC72, resulting in materials with lower poisoning rates and lower costs than Pd/C. Graphic abstract

Active Pd(ii) complexes: enhancing catalytic activity by ligand effect for carbonylation of methyl nitrite to dimethyl carbonate

2017 ◽  
Vol 7 (17) ◽  
pp. 3785-3790 ◽  
Author(s):  
Hong-Zi Tan ◽  
Zhi-Qiao Wang ◽  
Zhong-Ning Xu ◽  
Jing Sun ◽  
Zhe-Ning Chen ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Dimethyl Carbonate ◽  
Ligand Effect ◽  
Methyl Nitrite ◽  
Catalytic Activities

The catalytic activities of Pd(ii) complexes for carbonylation of methyl nitrite to dimethyl carbonate could be enhanced by ligand effect.

Synthesis and characterization of highly ordered MCM-41 in an alkali-free system and its catalytic activity

1996 ◽  
Vol 38 (1-2) ◽  
pp. 33-37 ◽  
Author(s):  
Xiu S. Zhao ◽  
Gao Q. Lu ◽  
Graeme J. Millar ◽  
Xin S. Li
Keyword(s):  
Catalytic Activity ◽  
Synthesis And Characterization ◽  
Free System ◽  
Mcm 41
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