scholarly journals Selective Styrene Oxidation to Benzaldehyde over Recently Developed Heterogeneous Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1680
Author(s):  
Marta A. Andrade ◽  
Luísa M. D. R. S. Martins
Keyword(s):  
Heterogeneous Catalysts ◽  
Carbon Materials ◽  
Oxygen Species ◽  
Styrene Oxidation ◽  
Reaction Conditions ◽  
Reactive Metal ◽  
Catalytic Systems ◽  
Tert Butyl Hydroperoxide ◽  
Metal Organic ◽  
Important Intermediate

The selective oxidation of styrene under heterogeneous catalyzed conditions delivers environmentally friendly paths for the production of benzaldehyde, an important intermediate for the synthesis of several products. The present review explores heterogeneous catalysts for styrene oxidation using a variety of metal catalysts over the last decade. The use of several classes of supports is discussed, including metal–organic frameworks, zeolites, carbon materials and silicas, among others. The studied catalytic systems propose as most used oxidants tert-butyl hydroperoxide, and hydrogen peroxide and mild reaction conditions. The reaction mechanism proceeds through the generation of an intermediate reactive metal–oxygen species by catalyst-oxidant interactions. Overall, most of the studies highlight the synergetic effects among the metal and support for the activity and selectivity enhancement.

scholarly journals Heterogeneous Catalysts for the Conversion of Glucose into 5-Hydroxymethyl Furfural

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 861
Author(s):  
Christiaan H. L. Tempelman ◽  
Ryan Oozeerally ◽  
Volkan Degirmenci
Keyword(s):  
Lignocellulosic Biomass ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Metal Organic Frameworks ◽  
Reaction Conditions ◽  
Catalytic Systems ◽  
Hydroxymethyl Furfural ◽  
Potential Applications ◽  
Metal Organic

Lignocellulosic biomass, a cheap and plentiful resource, could play a key role in the production of sustainable chemicals. The simple sugars contained in the renewable lignocellulosic biomass can be converted into commercially valuable products such as 5-hydroxymethyl furfural (HMF). A platform molecule, HMF can be transformed into numerous chemical products with potential applications in a wide variety of industries. Of the hexoses contained in the lignocellulosic biomass, the successful production of HMF from glucose has been a challenge. Various heterogeneous catalysts have been proposed over the last decade, ranging from zeolites to metal organic frameworks. The reaction conditions vary in the reports in the literature, which makes it difficult to compare catalysts reported in different studies. In addition, the slight variations in the synthesis of the same material in different laboratories may affect the activity results, because the selectivity towards desired products in this transformation strongly depends on the nature of the active sites. This poses another difficulty for the comparison of different reports. Furthermore, over the last decade the new catalytic systems proposed have increased profoundly. In this article, we summarize the heterogeneous catalysts: Metal Organic Frameworks (MOFs), zeolites and conventional supported catalysts, that have been reported in the recent literature and provide an overview of the observed catalytic activity, in order to provide a comparison.

scholarly journals Direct Catalytic Conversion of CO2 to Cyclic Organic Carbonates under Mild Reaction Conditions by Metal—Organic Frameworks

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 34 ◽  
Author(s):  
Seong Huh
Keyword(s):  
Metal Organic Framework ◽  
Cycloaddition Reaction ◽  
Co2 Concentration ◽  
Reaction Conditions ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Electrochemical Conversion ◽  
Modern Chemical ◽  
Metal Organic ◽  
Carbon Dioxide Co2

The reduction of the representative greenhouse gas, carbon dioxide (CO2), is significantly an important theme for the current research in the modern chemical world. For the last two decades, the development of new metal-organic framework (MOF) systems with highly selective capture of CO2, in the presence of other competing gaseous molecules, has flourished to capture or separate CO2 for environmental protection. Nonetheless, the ultimate resolution to lessen the atmospheric CO2 concentration may be in the chemical or electrochemical conversion of CO2 to other compounds. In this context, the catalytic cycloaddition reaction of CO2 into organic epoxides to produce cyclic carbonates is a more attractive method. MOFs are being proven as efficient heterogeneous catalytic systems for this important reaction. In this review, we collected very recent progress in MOF-based catalytic systems, fully operable under very mild reaction conditions (room temperature and 1 atm CO2).

scholarly journals Synthesis, Structures, Electrochemistry, and Catalytic Activity towards Cyclohexanol Oxidation of Mono-, Di-, and Polynuclear Iron(III) Complexes with 3-Amino-2-Pyrazinecarboxylate

2020 ◽  
Vol 10 (8) ◽  
pp. 2692
Author(s):  
Anirban Karmakar ◽  
Luísa M.D.R.S. Martins ◽  
Yuliya Yahorava ◽  
M. Fátima C. Guedes da Silva ◽  
Armando J. L. Pombeiro
Keyword(s):  
Coordination Polymer ◽  
Heterogeneous Catalysts ◽  
Saturated Calomel Electrode ◽  
Two Dimensional ◽  
Reaction Conditions ◽  
Ability To Act ◽  
Tert Butyl Hydroperoxide ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The synthesis and characterization of a set of iron(III) complexes, viz. the mononuclear [Fe(L)3] (1) and [NHEt3][Fe(L)2(Cl)2] (2), the dinuclear methoxido-bridged [Fe(L)2(μ-OMe)]2.DMF.1.5MeOH (3), and the heteronuclear Fe(III)/Na(I) two-dimensional coordination polymer [Fe(N3)(μ-L)2(μ-O)1/2(Na)(μ-H2O)1/2]n (4), are reported. Reactions of 3-amino-2-pyrazinecarboxylic acid (HL) with iron(III) chloride under different reaction conditions were studied, and the obtained compounds were characterized by elemental analysis, Fourier Transform Infrared (FT-IR) spectroscopy, and X-ray single-crystal diffraction. Compound 1 is a neutral mononuclear complex, whereas 2 is mono-anionic with its charge being neutralized by triethylammonium cation. Compounds 3 and 4 display a di-methoxido-bridged dinuclear complex and a two-dimensional heterometallic Fe(III)/Na(I) polynuclear coordination polymer, respectively. Compounds 3 and 4 are the first examples of methoxido- and oxido-bridged iron(III) complexes, respectively, with 3-amino-2-pyrazinecarboxylate ligands. The electrochemical study of these compounds reveals a facile single-electron reversible Fe(III)-to-Fe(II) reduction at a positive potential of 0.08V vs. saturated calomel electrode (SCE), which is in line with their ability to act as efficient oxidants and heterogeneous catalysts for the solvent-free microwave-assisted peroxidative oxidation (with tert-butyl hydroperoxide) of cyclohexanol to cyclohexanone (almost quantitative yields after 1 h). Moreover, the catalysts are easily recovered and reused for five consecutive cycles, maintaining a high activity and selectivity.

scholarly journals Copper(II) complex of (±)trans-1,2-cyclohexanediamine azo-linked Schiff base ligand encapsulated in nanocavity of zeolite-Y for the catalytic oxidation of olefins

2016 ◽  
Vol 81 (2) ◽  
pp. 153-162 ◽  
Author(s):  
Maryam Lashanizadegan ◽  
Sahar Shayegan ◽  
Marzieh Sarkheil
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Heterogeneous Catalysts ◽  
Zeolite Y ◽  
Schiff Base Complex ◽  
Reaction Conditions ◽  
Catalytic Behavior ◽  
Tert Butyl Hydroperoxide ◽  
Oxidation Of Olefins ◽  
Ft Ir

A Schiff base ligand derived from 4-(benzeneazo) salicylaldehyde and (?)trans-1,2-cyclohexanediamine (H2L) and its corresponding Cu(II) complex (CuL) has been synthesized and characterized by FT-IR, UV-VIS and 1H NMR. The copper Schiff base complex encapsulated in the nanopores of zeolite-Y (CuL-Y) by flexible ligand method and its encapsulation have been ensured by different studies. The homogeneous and its corresponding heterogeneous catalysts have been used for oxidation of different alkenes with tert-butyl hydroperoxide. Under the optimized reaction conditions, the oxidation of cyclooctene, cyclohexene, styrene and norbornene catalyzed by CuL gave 89, 63, 46 and 13% conversion, respectively. These olefins were oxidized efficiently with 50, 96, 96 and 92% conversion in the presence of CuL-Y, respectively. Comparison of the catalytic behavior of CuL and CuL-Y showed the higher catalytic activity and selectivity of the heterogeneous catalyst with respect to the homogenous one.

scholarly journals Hydrogen Production from Formic Acid Attained by Bimetallic Heterogeneous PdAg Catalytic Systems

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4027 ◽  
Author(s):  
Miriam Navlani-García ◽  
David Salinas-Torres ◽  
Diego Cazorla-Amorós
Keyword(s):  
Formic Acid ◽  
High Performance ◽  
Heterogeneous Catalysts ◽  
Carbon Materials ◽  
Pd Nanoparticles ◽  
Catalytic Performance ◽  
Catalytic Systems ◽  
Storage Technologies ◽  
The Impact ◽  
Great Focus

The production of H2 from the so-called Liquid Organic Hydrogen Carriers (LOHC) has recently received great focus as an auspicious option to conventional hydrogen storage technologies. Among them, formic acid, the simplest carboxylic acid, has recently emerged as one of the most promising candidates. Catalysts based on Pd nanoparticles are the most fruitfully investigated, and, more specifically, excellent results have been achieved with bimetallic PdAg-based catalytic systems. The enhancement displayed by PdAg catalysts as compared to the monometallic counterpart is ascribed to several effects, such as the formation of electron-rich Pd species or the increased resistance against CO-poisoning. Aside from the features of the metal active phases, the properties of the selected support also play an important role in determining the final catalytic performance. Among them, the use of carbon materials has resulted in great interest by virtue of their outstanding properties and versatility. In the present review, some of the most representative investigations dealing with the design of high-performance PdAg bimetallic heterogeneous catalysts are summarised, paying attention to the impact of the features of the support in the final ability of the catalysts towards the production of H2 from formic acid.

An Overview of Metal-organic Frameworks-based Acid/Base Catalysts for Biofuel Synthesis

2020 ◽  
Vol 24 (16) ◽  
pp. 1876-1891
Author(s):  
Qiuyun Zhang ◽  
Yutao Zhang ◽  
Jingsong Cheng ◽  
Hu Li ◽  
Peihua Ma
Keyword(s):  
Alternative Fuels ◽  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Flexible Structures ◽  
Biodiesel Production ◽  
Biodiesel Synthesis ◽  
Metal Organic ◽  
Organic Framework

Biofuel synthesis is of great significance for producing alternative fuels. Among the developed catalytic materials, the metal-organic framework-based hybrids used as acidic, basic, or supported catalysts play major roles in the biodiesel production. This paper presents a timely and comprehensive review of recent developments on the design and preparation of metal-organic frameworks-based catalysts used for biodiesel synthesis from various oil feedstocks, including MILs-based catalysts, ZIFs-based catalysts, UiO-based catalysts, Cu-BTC-based catalysts, and MOFs-derived porous catalysts. Due to their unique and flexible structures, excellent thermal and hydrothermal stability, and tunable host-guest interactions, as compared with other heterogeneous catalysts, metal-organic framework-based catalysts have good opportunities for application in the production of biodiesel at industrial scale.

scholarly journals Advances in Enzyme and Ionic Liquid Immobilization for Enhanced in MOFs for Biodiesel Production

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3512
Author(s):  
Reem Shomal ◽  
Babatunde Ogubadejo ◽  
Toyin Shittu ◽  
Eyas Mahmoud ◽  
Wei Du ◽  
...  
Keyword(s):  
Organic Ligands ◽  
Biodiesel Production ◽  
Catalyst Stability ◽  
Promising Candidate ◽  
Catalytic Systems ◽  
Highly Porous Materials ◽  
High Tunability ◽  
Catalytic Sites ◽  
Metal Organic ◽  
Highly Porous

Biodiesel is a promising candidate for sustainable and renewable energy and extensive research is being conducted worldwide to optimize its production process. The employed catalyst is an important parameter in biodiesel production. Metal–organic frameworks (MOFs), which are a set of highly porous materials comprising coordinated bonds between metals and organic ligands, have recently been proposed as catalysts. MOFs exhibit high tunability, possess high crystallinity and surface area, and their order can vary from the atomic to the microscale level. However, their catalytic sites are confined inside their porous structure, limiting their accessibility for biodiesel production. Modification of MOF structure by immobilizing enzymes or ionic liquids (ILs) could be a solution to this challenge and can lead to better performance and provide catalytic systems with higher activities. This review compiles the recent advances in catalytic transesterification for biodiesel production using enzymes or ILs. The available literature clearly indicates that MOFs are the most suitable immobilization supports, leading to higher biodiesel production without affecting the catalytic activity while increasing the catalyst stability and reusability in several cycles.

scholarly journals Recyclable Catalysts for Alkyne Functionalization

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3525
Author(s):  
Leslie Trigoura ◽  
Yalan Xing ◽  
Bhanu P. S. Chauhan
Keyword(s):  
Supported Catalysts ◽  
Metal Organic Framework ◽  
Metal Nanoparticle ◽  
Homogeneous Catalyst ◽  
Catalyst Recycling ◽  
Catalytic Systems ◽  
Recyclable Catalysts ◽  
Metal Organic ◽  
Porous Organic Framework ◽  
Organic Framework

In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have incorporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane-encapsulated novel metal nanoparticle-based catalysts, silica–copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic framework (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowledge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis.

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