scholarly journals Ethylene Trimerization over Supported SNS and PNP

2021 ◽  
Vol 75 ◽  
Author(s):  
Chromium Catalysts ◽  
Mzamo L. Shozi ◽  
Xolelwa Zulu ◽  
Holger B. Friedrich
Keyword(s):  
Supported Catalysts ◽  
Supported Catalyst ◽  
Catalytic Performance ◽  
Phosphine Ligands ◽  
Bet Surface Area ◽  
Nitrogen And Phosphorus ◽  
Reaction Conditions ◽  
Tridentate Ligands ◽  
Ethylene Trimerization ◽  
Influence Of Temperature On

ABSTRACT Chromium(III) complexes with sulphur, nitrogen and phosphorus tridentate ligands were synthesized and characterized. These complexes were supported on SiO2 and characterized by BET surface area measurements, XRF, SEM-EDX and FTIR. The complexes were tested for activity and selectivity in the trimerization of ethylene. The substituent's effect and influence on the sulphur on the supported catalysts were studied using the ethyl and the decyl substituted catalysts. The influence of temperature on catalytic performance was evaluated using the PPP supported system. The most active supported catalyst, the decyl substituted SNS catalyst, showed good activity of up to 19 500 g/g Cr h-1 and selectivity of 97.3 % to C6 products (98.2 % 1-hexene). This activity and selectivity were comparable to the homogeneous counterpart's performance that achieved 22 000 g/g Cr h-1 and 98.2 % C6 products (96.7 % 1-hexene), which surpassed the ethyl substituted catalyst, which was not supported, under the same reaction conditions. The supported PPP catalyst activities showed it was sensitive to higher temperatures, but this depends on the supporting technique. Keywords: Ethylene trimerization, sulfanyl ligands, phosphine ligands, supported catalysts.

scholarly journals Low-Rank Coal Supported Ni Catalysts for CO2 Methanation

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2040
Author(s):  
Soohyun Kim ◽  
Yunxia Yang ◽  
Renata Lippi ◽  
Hokyung Choi ◽  
Sangdo Kim ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Supported Catalysts ◽  
Catalyst Support ◽  
Supported Catalyst ◽  
Catalytic Performance ◽  
Process Efficiency ◽  
Low Rank ◽  
Ni Catalyst ◽  
Low Rank Coal ◽  
Co2 Methanation

As renewable energy source integration increases, P2G technology that can store surplus renewable power as methane is expected to expand. The development of a CO2 methanation catalyst, one of the core processes of the P2G concept, is being actively conducted. In this work, low-rank coal (LRC) was used as a catalyst support for CO2 methanation, as it can potentially enhance the diffusion and adsorption behavior by easily controlling the pore structure and composition. It can also improve the process efficiency owing to its simplicity (no pre-reduction step) and high thermal conductivity, compared to conventional metal oxide-supported catalysts. A screening of single metals (Ni, Co, Ru, Rh, and Pd) on LRC was performed, which showed that Ni was the most active. When Ni on the LRC catalyst was doped with a promoter (Ce and Mg), the CO2 conversion percentage increased by >10% compared to that of the single Ni catalyst. When the CO2 methanation activity was compared at 250–500 °C, the Ce-doped Ni/Eco and Mg-doped Ni/Eco catalysts showed similar or better activity than the commercial metal oxide-supported catalyst. In addition, the catalytic performance remained stable even after the test for an extended time (~200 h). The results of XRD, TEM, and TPR showed that highly efficient LRC-based CO2 methanation catalysts can be made when the metal dispersion and composition are modified.

Liquid-Phase Catalytic Oxidation of Styrene by a Fiber-Supported Copper(II) Complex with High Catalytic Performance

2014 ◽  
Vol 1033-1034 ◽  
pp. 61-64 ◽  
Author(s):  
Hong Hong Yang ◽  
Ge Wang ◽  
Shan Shan Yan ◽  
Jing Feng ◽  
Zhen Dong Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Temperature ◽  
Supported Catalyst ◽  
Catalytic Performance ◽  
Subsequent Treatment ◽  
High Catalytic Activity ◽  
Reaction Conditions ◽  
Tert Butyl Hydroperoxide ◽  
New Type ◽  
Polymer Supported

A new type of polymer-supported catalyst, [PS-(PBIM)2Cu (II)], was synthesized by loading 2-(2’-pyridyl) benzimidazole on chloromethylated propylene-styrene graft copolymer fiber and subsequent treatment with Cu (OAc)2 in methanol. The prepared catalyst was used in the oxidation of styrene with tert-butyl hydroperoxide (TBHP) as the oxidant. The important reaction conditions, such as the reaction temperature, the ratio of oxidant/styrene, and the recycle times were examined. The experimental results show that the catalyst reveals relatively high catalytic performance with 84% conversion for styrene. The suitable conditions are as follows: n (styrene):n (TBHP)=1:3, the reaction temperature of 80 °C and the reaction time of 8 h. In addition, the catalyst used repeatedly for 3 times can still possess high catalytic activity.

Structure and catalytic performance of Zn-doped TiO2 film

2019 ◽  
Vol 48 (6) ◽  
pp. 508-514 ◽  
Author(s):  
Mei Yang ◽  
Tingyu Huang ◽  
Ning Tang ◽  
Ben Ou ◽  
Wenhao Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Total Pore Volume ◽  
Methyl Orange Solution ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
Reaction Conditions ◽  
Content Type ◽  
Degradation Ratio ◽  
Micro Arc Oxidation ◽  
Kinetics Of

Purpose This paper aims to investigate the photocatalytic activity of zinc doped MAO-TiO2 films under the optimum MAO treatment condition. Design/methodology/approach The coating was prepared by micro arc oxidation, and the influence of doping on the properties of the coating was also investigated. Findings The results show that the BET surface area is 78.25±0.03m2/g, total pore area is 76.32 ± 0.04m2/g, and the total pore volume is 0.2135 ± 0.0004cm3/g. The degradation ratio of the film electrode with Zn-doped in methyl orange solution is up to 94%. When the react circles is 10 times, the degradation ratio is up to more than 85% and remains steady. With the different reaction conditions, these kinetics of the reactions show some different formulas. Originality/value A kinetic equation for photocatalytic activity is established.

Synthesis of Glycerol Carbonate by Transesterification of Glycerol with Dimethyl Carbonate over Mg-Al Mixed Oxides Supported on MCM-41

2014 ◽  
Vol 1008-1009 ◽  
pp. 319-322
Author(s):  
Gong De Wu ◽  
Xiao Li Wang ◽  
Zhi Li Zhai ◽  
Ao Yun Cao
Keyword(s):  
Dimethyl Carbonate ◽  
Mixed Oxides ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Glycerol Carbonate ◽  
Reaction Conditions ◽  
Glycerol Conversion ◽  
Mcm 41

The Mg-Al mixed oxides were deposited on the MCM-41 via the coprecipitation followed by thermal decomposition and characterized by many techniques. In the transesterification of glycerol (GL) with dimethyl carbonate (DMC), the resulting supported catalysts exhibited much higher catalytic performance than the pure Mg-Al mixed oxides, which was ascribed to the increased basicity. Under the optimal reaction conditions, the obtained data showed that at DMC/glycerol molar ratio of 3:1, catalyst loading of 0.3 g and reaction temperature of 373 K, the glycerol conversion and glycerol carbonate yield from the process was 98.7 % and 92.5%, respectively.

Different Crystal Form Titania Supported Ruthenium Nanoparticles for Liquid Phase Hydrodeoxygenation of Guaiacol

2018 ◽  
Vol 18 (12) ◽  
pp. 8426-8436 ◽  
Author(s):  
Wei Long ◽  
Yang Lv ◽  
Pingle Liu ◽  
Fang Hao ◽  
Wei Xiong ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Reaction Path ◽  
Supported Catalyst ◽  
Crystal Form ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
Ruthenium Nanoparticles ◽  
Crystal Forms ◽  
Anatase Titania ◽  
Rutile Titania

Titania supported Ruthenium-based catalysts were prepared for liquid phase hydrodeoxygenation of guaiacol to cyclohexanol. The catalytic performance is affected by the different crystal forms of titania supports. Anatase and rutile titania supported catalyst 5%Ru/a-r-TiO2 presents higher BET surface area, better dispersion of Ru particles with smaller particle size of 3–4 nm, more acidic centers, and more Ruδ+ located at the boundary between anatase titania and rutile titania. Hence, 5%Ru/a-r-TiO2 gives the best catalytic performance of 95.33% conversion of guaiacol and 79.23% selectivity to cyclohexanol, other products mainly include cyclohexane, benzene, cyclohexanone and 1,2-cyclohexanediol. Based on the results of this work, the possible reaction path for guaiacol hydrodeoxygenation was proposed.

scholarly journals Nickel Phosphide Catalysts as Efficient Systems for CO2 Upgrading via Dry Reforming of Methane

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 446
Author(s):  
Miriam González-Castaño ◽  
Estelle le Saché ◽  
Cameron Berry ◽  
Laura Pastor-Pérez ◽  
Harvey Arellano-García ◽  
...  
Keyword(s):  
Supported Catalysts ◽  
Lower Surface ◽  
Catalytic Performance ◽  
Dry Reforming Of Methane ◽  
Oxidation Reactions ◽  
Surface Areas ◽  
Ceo2 Sample ◽  
Conversion Rates ◽  
Ni Oxidation ◽  
Catalytic Behaviour

This work establishes the primordial role played by the support’s nature when aimed at the constitution of Ni2P active phases for supported catalysts. Thus, carbon dioxide reforming of methane was studied over three novel Ni2P catalysts supported on Al2O3, CeO2 and SiO2-Al2O3 oxides. The catalytic performance, shown by the catalysts’ series, decreased according to the sequence: Ni2P/Al2O3 > Ni2P/CeO2 > Ni2P/SiO2-Al2O3. The depleted CO2 conversion rates discerned for the Ni2P/SiO2-Al2O3 sample were associated to the high sintering rates, large amounts of coke deposits and lower fractions of Ni2P constituted in the catalyst surface. The strong deactivation issues found for the Ni2P/CeO2 catalyst, which also exhibited small amounts of Ni2P species, were majorly associated to Ni oxidation issues. Along with lower surface areas, oxidation reactions might also affect the catalytic behaviour exhibited by the Ni2P/CeO2 sample. With the highest conversion rate and optimal stabilities, the excellent performance depicted by the Ni2P/Al2O3 catalyst was mostly related to the noticeable larger fractions of Ni2P species established.

scholarly journals Novel Nickel- and Magnesium-Modified Cenospheres as Catalysts for Dry Reforming of Methane at Moderate Temperatures

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1066 ◽  
Author(s):  
Bogdan Samojeden ◽  
Marta Kamienowska ◽  
Armando Izquierdo Colorado ◽  
Maria Elena Galvez ◽  
Ilona Kolebuk ◽  
...  
Keyword(s):  
Supported Catalysts ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Temperature Programmed Reduction ◽  
Fly Ashes ◽  
Coal Fly Ashes ◽  
Temperature Programmed ◽  
Mg Content

Cenospheres from coal fly ashes were used as support in the preparation of Ni–Mg catalysts for dry reforming of methane. These materials were characterized by means of XRD, H2-temperature-programmed reduction (H2-TPR), CO2-temperature-programmed desorption (CO2-TPD), and low-temperature nitrogen sorption techniques. The cenosphere-supported catalysts showed relatively high activity and good stability in the dry reforming of methane (DRM) at 700 °C. The catalytic performance of modified cenospheres was found to depend on both Ni and Mg content. The highest activity at 750 °C and 1 atm was observed for the catalyst containing 30 wt % Mg and 10, 20, and 30 wt % Ni, yielding to CO2 and CH4 conversions of around 95%.

scholarly journals Novel Preparation of Cu and Fe Zirconia Supported Catalysts for Selective Catalytic Reduction of NO with NH3

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
Katarzyna Świrk ◽  
Ye Wang ◽  
Changwei Hu ◽  
Li Li ◽  
Patrick Da Costa ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Experimental Conditions ◽  
One Pot ◽  
Nh3 Scr ◽  
Scr Of No ◽  
Temperature Programmed ◽  
Stationary Sources

Copper and iron promoted ZrO2 catalysts were prepared by one-pot synthesis using urea. The studied catalysts were characterized by XRD, N2 physisorption, XPS, temperature-programmed desorption of NH3 (NH3-TPD), and tested by the selective catalytic reduction by ammonia (NH3-SCR) of NO in the absence and presence of water vapor, under the experimental conditions representative of exhaust gases from stationary sources. The influence of SO2 on catalytic performance was also investigated. Among the studied catalysts, the Fe-Zr sample showed the most promising results in NH3-SCR, being active and highly selective to N2. The addition of SO2 markedly improved NO and NH3 conversions during NH3-SCR in the presence of H2O. The improvement in acidic surface properties is believed to be the cause.

scholarly journals USE OF CERAMIC MATERIAL (CEMENT CLINKER) FOR THE PRODUCTION OF BIODIESEL

2013 ◽  
Vol 22 ◽  
pp. 71-78
Author(s):  
SUNNY SONI ◽  
MADHU AGARWAL
Keyword(s):  
Soybean Oil ◽  
Edible Oils ◽  
Methyl Esters ◽  
Catalytic Performance ◽  
Cement Clinker ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Rural Economic Development ◽  
Additional Demand ◽  
Biodiesel Fuels

Biodiesel is a renewable liquid fuel made from natural, renewable biological sources such as edible and non edible oils. Over the last years, biodiesel has gained more market due to its benefits and because it appears as the natural substitute for diesel. Reasons for growing interest in biodiesel include its potential for reducing noxious emissions, potential contributions to rural economic development, as an additional demand center for agricultural commodities, and as a way to reduce reliance on foreign oil. Biodiesel was prepared from soybean oil by transesterification with methanol in the presence of cement clinker. Cement clinker was examined as a catalyst for a conversion of soybean oil to fatty acid methyl esters (FAMEs). It can be a promising heterogeneous catalyst for the production of biodiesel fuels from soybean oil because of high activity in the conversion and no leaching in the transesterification reaction. The reaction conditions were optimized. A study for optimizing the reaction parameters such as the reaction temperature, and reaction time, was carried out. The catalyst cement clinker composition was characterized by XRF. The results demonstrate that the cement clinker shows high catalytic performance & it was found that the yield of biodiesel can reach as high as 84.52% after 1 h reaction at 65°C, with a 6:1 molar ratio of methanol to oil, 21 wt% KOH/cement clinker as catalyst.

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