scholarly journals Active Razor Shell CaO Catalyst Synthesis for Jatropha Methyl Ester Production via Optimized Two-Step Transesterification

2017 ◽  
Vol 2017 ◽  
pp. 1-20 ◽  
Author(s):  
A. N. R. Reddy ◽  
A. A. Saleh ◽  
M. S. Islam ◽  
S. Hamdan
Keyword(s):  
Methyl Ester ◽  
Heterogeneous Catalysts ◽  
Methyl Esters ◽  
High Surface ◽  
High Surface Area ◽  
Coefficient Of Determination ◽  
Catalyst Synthesis ◽  
Surface Method ◽  
Green Technique ◽  
Central Composite

Calcium based catalysts have been studied as promising heterogeneous catalysts for production of methyl esters via transesterification; however a few were explored on catalyst synthesis with high surface area, less particle size, and Ca leaching analysis. In this work, an active Razor shell CaO with crystalline size of 87.2 nm, SBET of 92.63 m2/g, pore diameters of 37.311 nm, and pore volume of 0.613 cc/g was synthesized by a green technique “calcination-hydro aeration-dehydration.” Spectrographic techniques TGA/DTA, FTIR, SEM, XRD, BET&BJH, and PSA were employed for characterization and surface morphology of CaO. Two-step transesterification of Jatropha curcas oil was performed to evaluate CaO catalytic activity. A five-factor-five-level, two-block, half factorial, central composite design based response surface method was employed for experimental analysis and optimization of Jatropha methyl ester (JME) yield. The regression model adequacy ascertained thru coefficient of determination (R2: 95.81%). A JME yield of 98.80% was noted at C (3.10 wt.%), M (54.24 mol./mol.%), T (127.87 min), H (51.31°C), and R (612 rpm). The amount of Ca leached to JME during 1st and 4th reuse cycles was 1.43 ppm ± 0.11 and 4.25 ppm ± 0.21, respectively. Higher leaching of Ca, 6.67 ppm ± 1.09, was found from the 5th reuse cycle due to higher dispersion of Ca2+; consequently JME yield reduces to 76.40%. The JME fuel properties were studied according to biodiesel standards EN 14214 and comply to use as green biodiesel.

Electron holography of catalysts

1995 ◽  
Vol 53 ◽  
pp. 416-417
Author(s):  
A. K. Datye ◽  
D. S. Kalakkad ◽  
L. F. Allard ◽  
E. Völkl
Keyword(s):  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Scale ◽  
Nano Particles ◽  
Phase Image ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Phase Information ◽  
Particle Structure

The active phase in heterogeneous catalysts consists of nanometer-sized metal or oxide particles dispersed within the tortuous pore structure of a high surface area matrix. Such catalysts are extensively used for controlling emissions from automobile exhausts or in industrial processes such as the refining of crude oil to produce gasoline. The morphology of these nano-particles is of great interest to catalytic chemists since it affects the activity and selectivity for a class of reactions known as structure-sensitive reactions. In this paper, we describe some of the challenges in the study of heterogeneous catalysts, and provide examples of how electron holography can help in extracting details of particle structure and morphology on an atomic scale.Conventional high-resolution TEM imaging methods permit the image intensity to be recorded, but the phase information in the complex image wave is lost. However, it is the phase information which is sensitive at the atomic scale to changes in specimen thickness and composition, and thus analysis of the phase image can yield important information on morphological details at the nanometer level.

Metal nanoparticles: ligand free approach towards coupling reactions

2021 ◽  
Vol 01 ◽  
Author(s):  
Sharwari K. Mengane ◽  
Ronghui Wu ◽  
Liyun Ma ◽  
Chhaya S. Panse ◽  
Shailesh N. Vajekar ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Metal Nanoparticles ◽  
Surface Area ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Medium ◽  
Coupling Reactions ◽  
Research Activities ◽  
Ligand Free

: Catalysis is the multidisciplinary field involving many areas of chemistry, notably in organometallic chemistry and materials science. It has great applications in synthesis of many industrially applicable compounds such as fuels and fine chemicals. The activity and selectivity are a key issue in catalysis that generally allied to high surface area. The current research activities mainly deal with the homogeneous and heterogeneous catalysis. Homogeneous and heterogeneous catalysis have certain drawbacks which restricts their application to great extent but have their own advantages. Hence, it has a predominant concern of current research to find out an alternate to overcome their drawbacks. Therefore, it is highly desirable to find a catalytic protocol that offers high selectivity and excellent product yield with quick and easy recovery. Along with their various applications as alternatives to conventional bulk materials nanomaterial have established its great role in different industrial and scientific applications. Nanocatalysis has emerged as new alternative to the conventional homogeneous and heterogeneous catalysis. The nanomaterials are responsible to enhance surface area of the catalyst, which ultimately increases the catalyst reactants contacts. In addition, it acts as robust material and has high surface area like heterogeneous catalysts. Insolubility of such nanomaterial in reaction medium makes them easily separable, hence, catalyst can be easily separate from the product. Hence, it has been proven that nanocatalysts behave like homogeneous as well as heterogeneous catalysts which work as a bridge between the conventional catalytic systems. Considering these merits; researchers has paid their attention towards applications of nanocatalyst in several organic reactions. This review article focused on the catalytic applications of metal nanoparticles (MNPs) such as Pd, Ag, Au, Cu, Pt in ligand free coupling reactions. In addition, it covers applications of bimetallic and multimetallic nanoparticles in ligand free coupling reactions.

scholarly journals Carbon-Based Catalysts for Biodiesel Production—A Review

2020 ◽  
Vol 10 (3) ◽  
pp. 918 ◽  
Author(s):  
Jack Clohessy ◽  
Witold Kwapinski
Keyword(s):  
Heterogeneous Catalysts ◽  
Catalyst Activity ◽  
High Surface ◽  
High Surface Area ◽  
Acid Catalyst ◽  
Biodiesel Production ◽  
Catalyst Characterization ◽  
Synthesis Methods ◽  
And Performance ◽  
Carbon Based

In recent years, a new class of superior heterogeneous acid catalyst for biodiesel production has emerged. These catalysts offer advantages over their predecessors such as high surface area, elevated acid site density, enhanced catalyst activity, good operation stability and relevant economic affordability in an environmentally friendly frame. This review was concerned with carbon-based solid acid (CBAS) catalysts derived from both carbohydrate and pyrolysis products. A series of CBASs with various origins such as D-glucose, sucrose, starch, cellulose and vegetable oil asphalt, converted to char and sulphonated, have been explored as potential heterogeneous catalysts. Catalyst preparation and synthesis methods were briefly summarized. Catalyst characterization and performance for biofuels related reactions were elucidated, identifying potential research applications. Three catalysts in particular were identified as having potential for industrial application and requiring further research.

scholarly journals Generalized synthesis of high surface area mesoporous metal titanates as efficient heterogeneous catalysts

2020 ◽  
Vol 19 ◽  
pp. 100570
Author(s):  
Wimalika R.K. Thalgaspitiya ◽  
Tharindu Kankanam Kapuge ◽  
Dinithi Rathnayake ◽  
Junkai He ◽  
William S. Willis ◽  
...  
Keyword(s):  
Surface Area ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Mesoporous Metal

Synthesis of Mesoporous Tungsten Oxide/γ-Alumina and Surfactant-Capped Tungsten Oxide Nanoparticles and Their Catalytic Activities in Oxidative Cleavage of Oleic Acid

2016 ◽  
Vol 14 (4) ◽  
pp. 899-907 ◽  
Author(s):  
Amir Enferadi Kerenkan ◽  
Aimé Serge Ello ◽  
Bousselham Echchahed ◽  
Trong-On Do
Keyword(s):  
Tungsten Oxide ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Oxidative Cleavage ◽  
Type I ◽  
Type Ii ◽  
Catalytic Activities ◽  
Tungsten Oxide Nanoparticles ◽  
Catalytic Test

Abstract Unsaturated fatty acids can be converted into mono and dicarboxylic acids, which are applicably valuable materials, through oxidative cleavage reaction in the presence of a highly efficient catalyst/oxidant system. In this work, two types of advanced heterogeneous catalysts have been developed; (i) high surface area mesoporous tungsten oxide/γ-alumina mixed metal oxide, and (ii) surfactant-capped tungsten oxide nanoparticles. Various technique including N2 adsorption/desorption isotherms, XRD, SEM, EDS, TGA and catalytic test were used to monitor the physicochemical and catalytic properties of these materials. The characterization results revealed that type (i) materials exhibit high surface area and narrow particle size distribution, and the used surfactant could quantitatively enough cap the surface of type (ii) materials. The catalytic activities of these materials in the oxidative cleavage of oleic acid with H2O2 as oxidant were investigated. GC-MS was used to determine the produced amounts of desired products, azelaic and pelargonic acids. The catalytic test results showed more than 90 % conversion for type (ii) catalyst in 5 h reaction at 120 °C with acceptable production yields for azelaic and pelargonic acids. The significantly higher activity of this catalyst compared to type (i) arises from the interesting surface properties of tungsten oxides nanoparticles, which make them able to exploit the good features of homogeneous and heterogeneous catalysts.

Synthesis of High Surface Area ZnO(0001) Plates as Novel Oxide Supports for Heterogeneous Catalysts

2010 ◽  
Vol 139 (1-2) ◽  
pp. 26-32 ◽  
Author(s):  
Patrick D. Burton ◽  
Eric J. Peterson ◽  
Timothy J. Boyle ◽  
Abhaya K. Datye
Keyword(s):  
Surface Area ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Oxide Supports

In Situ and Ex Situ Microscopic Study of Propylene Polymerization With Heterogeneous Mgcl2-Supported Ziegler-Natta Catalysts

2000 ◽  
Vol 6 (S2) ◽  
pp. 33-34
Author(s):  
V. Oleshko ◽  
P. Crozier ◽  
R. Cantrell ◽  
A. Westwood
Keyword(s):  
Large Scale ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
Light And Electron Microscopy ◽  
High Surface Area ◽  
Propylene Polymerization ◽  
Ex Situ ◽  
Co Catalysts ◽  
Ziegler Natta Catalysts

The large-scale commercial production of polyolefins by catalytic Ziegler-Natta polymerization have stimulated the development of the third, fourth and fifth generation heterogeneous catalysts comprising high surface area defective MgCl2 with TiCl4, electron donors, and AlR3-co-catalysts. In spite of intensive research over the years, the present level of understanding of the catalysts is still incomplete because of their complex composition leading to a multitude of local active site environments. The aim of this work is to provide a new insight into the process via in situ video microscopy of gas phase propylene polymerization over MgCl2-supported Ziegler-Natta catalysts combined with ex situ characterization by light and electron microscopy techniques (SEM, TEM, HRTEM, STEM, PEELS and windowless EDX). Procedures for catalyst synthesis are described elsewhere. The catalysts were stored in a dry box under a He atmosphere (<lppm H2O/O2). Samples were transferred to specimen holders in the dry box and then transferred into the microscopes under high purge N2 conditions to prevent poisoning of the catalysts by air and moisture.

Ce–Zr materials with a high surface area as catalyst supports for hydrogenation of CO2

2020 ◽  
Vol 13 (04) ◽  
pp. 2040004
Author(s):  
Nikolay D. Evdokimenko ◽  
Alexander L. Kustov ◽  
Konstantin O. Kim ◽  
Igor V. Mishin ◽  
Vera D. Nissenbaum ◽  
...  
Keyword(s):  
Surface Area ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Oxygen Storage Capacity ◽  
Hydrogenation Reaction ◽  
Oxygen Storage ◽  
Hexadecyltrimethylammonium Bromide ◽  
Developed Surface ◽  
Direct Hydrogenation

The most promising way of CO2 utilization is its catalytic conversion into valuable products, in particular, the direct hydrogenation of CO2 on heterogeneous catalysts to obtain such products as synthesis gas, hydrocarbons, alcohols, esters, carboxylic acids, and some other organic molecules. Heterogeneous iron-based catalysts possess a special position among the promising candidates for the synthesis of CO2-based hydrocarbons. However, individual iron oxide catalysts have a fairly low surface area, which requires their deposition on the support or modification. CeO2 is rather attractive in catalysis because of its high oxygen storage capacity. The most effective thermal stabilizer of CeO2 is ZrO2. In this work, cerium–zirconium systems with various Ce to Zr ratios were synthesized by the method of coprecipitation in the absence and presence of the hexadecyltrimethylammonium bromide template. These systems were characterized by adsorption of N2, XRD, and DTA-TG-DTG and used as supports for 5% Fe catalysts. The activity of synthesized Fe-containing catalysts was investigated in the reaction of CO2 hydrogenation. The developed surface and the presence of cerium in the supports are the possible reasons for the high activity of Fe-containing catalysts in the hydrogenation reaction of CO2.

Using New Porous Nanocomposites for Photocatalytic Water Decontamination

2008 ◽  
Vol 1145 ◽  
Author(s):  
Maryam Zarei Chaleshtori ◽  
S. M. Sarif Masud ◽  
Geoffrey B. Saupe
Keyword(s):  
Organic Contaminants ◽  
Heterogeneous Catalysts ◽  
Organic Pollutant ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Polluted Water ◽  
Particle Sizes ◽  
Water Decontamination ◽  
Physical And Chemical

AbstractHeterogeneous catalysts that accelerate the photolytic destruction of organic contaminants in water are a potentially inexpensive and highly effective way to remove both trace-level and saturated harmful compounds from industrial waste streams and drinking water. Porous photocatalytic materials can have the combined qualities of high surface area and relatively large particle sizes, as compared with nanoparticulate catalyst powders like titanium dioxide . The larger particle sizes of the porous materials facilitate catalyst removal from a solution, after purification has taken place.We have synthesized new kinds of photocatalytic porous oxide materials that can be used to purify contaminated water by accelerating the photodegradation of any kind of organic pollutant. The new materials have very large open pore structures that facilitate the diffusion, the surface contact of contaminants, and solvent flow through the catalyst. These qualities enhance surface reactions important to the process. The new catalysts have shown robust physical and chemical properties that make them candidates for real applications in polluted water decontamination.

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