scholarly journals On the Effect of the M3+ Origin on the Properties and Aldol Condensation Performance of MgM3+ Hydrotalcites and Mixed Oxides

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 992
Author(s):  
Valeriia Korolova ◽  
Oleg Kikhtyanin ◽  
Martin Veselý ◽  
Dan Vrtiška ◽  
Iva Paterová ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Aldol Condensation ◽  
Catalytic Performance ◽  
Atomic Weight ◽  
Solid Base ◽  
Acid Base ◽  
Advanced Biofuels ◽  
Solid Base Catalysts ◽  
Base Catalysts ◽  
The Relationship

Hydrotalcites (HTCs) are promising solid base catalysts to produce advanced biofuels by aldol condensation. Their main potential lies in the tunability of their acid-base properties by varying their composition. However, the relationship between the composition of hydrotalcites, their basicity, and their catalytic performance has not yet been fully revealed. Here, we investigate systematically the preparation of HTCs with the general formula of Mg6M3+2(OH)16CO3·4H2O, where M3+ stands for Al, Ga, Fe, and In, while keeping the Mg/M3+ equal to 3. We use an array of analytical methods including XRD, N2 physisorption, CO2-TPD, TGA-MS, FTIR-ATR, and SEM to assess changes in the properties and concluded that the nature of M3+ affected the HTC crystallinity. We show that the basicity of the HTC-derived mixed oxides decreased with the increase in atomic weight of M3+, which was reflected by decreased furfural conversion in its aldol condensation with acetone. We demonstrate that all MgM3+ mixed oxides can be fully rehydrated, which boosted their activity in aldol condensation. Taking all characterization results together, we conclude that the catalytic performance of the rehydrated HTCs is determined by the “host” MgO component, rather than the nature of M3+.

Mg–Fe mixed oxides as solid base catalysts for the transesterification of microalgae oil

RSC Advances ◽  
2015 ◽  
Vol 5 (87) ◽  
pp. 71278-71286 ◽  
Author(s):  
Sheng Xu ◽  
Hong-Yan Zeng ◽  
Chao-Rong Cheng ◽  
Heng-Zhi Duan ◽  
Jing Han ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Catalytic Performance ◽  
Solid Base ◽  
Solid Base Catalysts ◽  
Molar Ratios ◽  
Base Catalysts ◽  
Microalgae Oil

Mg–Fe LDO with different Mg/Fe molar ratios as catalysts were adopted for transesterification of microalgae oil, and the catalytic performance of the catalysts was closely related to their basicity and crystallinity.

scholarly journals Environmentally Benign Neem Biodiesel Synthesis Using Nano-Zn-Mg-Al Hydrotalcite as Solid Base Catalysts

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Karthikeyan Chelladurai ◽  
Manivannan Rajamanickam
Keyword(s):  
Methyl Esters ◽  
Catalytic Performance ◽  
Environmentally Benign ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Solid Base ◽  
Synthetic Compound ◽  
Solid Base Catalysts ◽  
Base Catalysts ◽  
Biodiesel Synthesis

Hydrotalcite, also known as aluminum-magnesium layered double hydroxide (LDH) or anionic clay, is a synthetic compound that was broadly investigated in the past decade due to its many potential applications. In this work, we present an environmentally benign process for the transesterification (methanolysis) of neem oil to fatty acid methyl esters (FAME) using Zn-Mg-Al hydrotalcites as solid base catalysts in a heterogeneous manner. The catalysts were characterized by XRD, FT-IR, TPD-CO2, and the BET surface area analysis. It is well-known that the catalytic performance of hydrotalcite is dramatically increased through the incorporation of Zn into the surface of Mg-Al hydrotalcite material. The optimized parameters, 10 : 1 methanol/oil molar ratio with 7.5 g catalysts reacted under stirring speed 450 rpm at 65°C for 4 h reaction, gave a maximum ester conversion of 90.5% for the sample with Zn-Mg-Al ratio of 3 : 3 : 1.

scholarly journals Utilization of Carbide Lime Waste as Base Catalyst for Biodiesel Production

2018 ◽  
Vol 7 (4.35) ◽  
pp. 700 ◽  
Author(s):  
Koguleshun Subramaniam ◽  
Sasidevan Munusamy ◽  
Fei-ling Pua ◽  
Mohd Aizat Mohd Nasir ◽  
Rohaya Othman ◽  
...  
Keyword(s):  
Ester Group ◽  
Catalytic Performance ◽  
Biodiesel Production ◽  
Strength Analysis ◽  
Solid Base ◽  
Base Catalyst ◽  
Solid Base Catalyst ◽  
X Ray ◽  
Solid Base Catalysts ◽  
Base Catalysts

Calcium rich solid base catalyst was synthesized from local waste carbide lime and its catalytic performance was evaluated via biodiesel production. Carbide lime waste was used to produce CLW-I and CLW-II solid base catalyst using different preparation methods. Characterization including base strength analysis, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were investigated. Catalytic strength was examined by deploying the solid base catalysts for transesterification reaction of palm oil. Fourier Transform Infra-red (FTIR) was used to analyze the presence of ester group in biodiesel. The yield of biodiesel conversion was calculated based on the mass of biodiesel and glycerol. The highest biodiesel conversion rate of 75.30% was achieved by CLW-I solid base catalyst at 9% loading. The good catalytic performance of carbide lime waste derived solid base catalysts proves that it has high potential to replace the usage of conventional catalyst in the biodiesel industry.

Methylation of cyclopentadiene on solid base catalysts with different surface acid–base properties

2010 ◽  
Vol 275 (2) ◽  
pp. 257-269 ◽  
Author(s):  
Dongxue Lan ◽  
Li Ma ◽  
Yuan Chun ◽  
Chen Wu ◽  
Linbing Sun ◽  
...  
Keyword(s):  
Solid Base ◽  
Acid Base ◽  
Solid Base Catalysts ◽  
Base Catalysts ◽  
Base Properties

Greener Methodology: An Aldol Condensation of an Unprotected C-Glycoside with Solid Base Catalysts

2018 ◽  
Vol 6 (6) ◽  
pp. 7810-7817 ◽  
Author(s):  
Tamara M. de Winter ◽  
Laurène Petitjean ◽  
Hanno C. Erythropel ◽  
Magali Moreau ◽  
Julien Hitce ◽  
...  
Keyword(s):  
Aldol Condensation ◽  
Solid Base ◽  
Solid Base Catalysts ◽  
Base Catalysts

Formation of Methyl Acrylate from Methyl Acetate and Formaldehyde Condensation over Solid Base Catalysts

2012 ◽  
Vol 629 ◽  
pp. 376-380 ◽  
Author(s):  
Ya Nan Wang ◽  
Qun Long Wang ◽  
Huan Hui Chen ◽  
Jia Lei Zhang ◽  
Zhi Rong Zhu
Keyword(s):  
Acrylic Acid ◽  
Vapor Phase ◽  
Methyl Acrylate ◽  
Methyl Acetate ◽  
Aldol Condensation ◽  
Solid Base ◽  
Base Property ◽  
Support Materials ◽  
Solid Base Catalysts ◽  
Base Catalysts

The vapor-phase aldol condensation of methyl acetate (MeOAC) with formaldehyde (HCHO) to form methyl acrylate was investigated over solid base catalysts. A variety of solid base catalysts were prepared by loading Cs2O over SiO2 or Al2O3 as the support materials. The properties of the solid base catalysts were characterized by XRD, BET and CO2-TPD. The results of the vapor-phase aldol condensation indicated that SiO2 and Al2O3 modified with Cs2O showed high conversation of methyl acetate and high selectivity of methyl acrylate. 22.6% conversation of methyl acetate and 16.5% yield of acrylic acid and methyl acrylate were obtained over Cs-Al2O3. In addition, Cs-SiO2 exhibited about 42% selectivity to methyl acetate. The high yield of acrylic acid and methyl acrylate is attributed to the high base property of catalysts.

Preparation of MgAlY-LDO Solid Base Catalysts and their Catalytic Performance on the Synthesis of Isophorone via Acetone Condensation

2012 ◽  
Vol 550-553 ◽  
pp. 424-428 ◽  
Author(s):  
Jian Jie Zhang ◽  
Zi Li Liu ◽  
Zu Zeng Qin ◽  
Yan Liu ◽  
Qi Ying Wang ◽  
...  
Keyword(s):  
Layer Structure ◽  
Catalytic Performance ◽  
Solid Base ◽  
Doping Amount ◽  
Strong Base ◽  
Solid Base Catalysts ◽  
Base Catalysts ◽  
Al Composite ◽  
Temperature Programmed ◽  
Acetone Condensation

Mg-Al composite oxide (MgAlY-LDO) solid base catalysts were prepared via the coprecipitation method, followed by calcinations at high temperatures. Isophorone synthesis from acetone condensation was also investigated. The catalysts were characterized via X-ray diffraction analysis, Fourier transform infrared spectroscopy, CO2 temperature-programmed desorption, and Brunauer-Emmett-Teller analysis. After doping with Y, the MgAl-LDO showed higher catalytic activity at a reaction temperature of 300 °C, 100 kPa and WHSV 6.3 h-1. Furthermore, the conversion of acetone and the selectivity of isophorone increased from 17.8% and 11.0% to 37.5% and 58.7%, respectively. These results indicate that the basicity of MgAlY-LDO as well as the number of its strong base centers increased after Y doping. The pore volume and size of MgAlY-LDO increased because of the increased hydrotalcite layer space caused by the big Y3+ ion. However, the crystal structure of hydrotalcite was remained. Y2O3 was evenly dispersed in MgAlY-LDO at low Y doping amounts. As the doping amount increased, the layer structure of hydrotalcite became distorted, thereby affecting the crystallinity of the hydrotalcite. Some Y3+ ions emerged from the Mg2+ lattice after doping with a high Y3+ concentration.

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