Journal articles: 'Solid Catalysts'

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Newman, R. A., J. A. Blazy, T. G. Fawcett, L. F. Whiting, and R. A. Stowe. "Use of the Dow-Developed DSC/XRD/MS in the Study of Several Model Copper-Based Catalyst Systems." Advances in X-ray Analysis 30 (1986): 493–502. http://dx.doi.org/10.1154/s0376030800021650.

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Due to the difficulty of analyzing materials at high temperatures and in reactive atmospheres, solid-state catalysts have often been developed with little knowledge of the true chemical behavior of the catalyst, except on a bulk scale. In the field of solid-state catalysis research, a great deal of time and effort is presently being spent to better characterize the chemical and physical properties which determine a particular catalyst‘s efficiency, lifetime, and selectivity. Recently, we have undertaken a study of model copper catalysts at The Dow Chemical Company in an effort to better understand the chemical and physical properties which determine the efficiency, regenerability, and lifetime of this type of solid state catalyst.

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Chen, Huihui, Zhenhua Dong, and Jun Yue. "Advances in Microfluidic Synthesis of Solid Catalysts." Powders 1, no. 3 (August 4, 2022): 155–83. http://dx.doi.org/10.3390/powders1030011.

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Heterogeneous catalysis plays a central role in the chemical and energy fields, owing to the high and tunable activities of solid catalysts that are essential to achieve the favorable reaction process efficiency, and their ease of recycle and reuse. Numerous research efforts have been focused on the synthesis of solid catalysts towards obtaining the desired structure, property and catalytic performance. The emergence and development of microfluidic reactor technology provide a new and attractive platform for the controllable synthesis of solid catalysts, primarily because of its superior mixing performance and high heat/mass transfer efficiency. In this review, the recent research progress on the synthesis of solid catalysts based on microfluidic reactor technology is summarized. The first section deals with the synthesis strategies for solid catalysts, including conventional methods in batch reactors and microfluidic alternatives (based on single- and two-phase flow processing). Then, different kinds of solid catalysts synthesized in microflow are discussed, especially with regard to the catalyst type, synthetic process, structure and property, and catalytic performance. Finally, challenges in the microreactor operation and scale-up, as well as future perspectives in terms of the synthesis of more types of catalysts, catalyst performance improvement, and the combination of catalyst synthesis process and catalytic reaction in microreactors, are provided.

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Gates, Bruce C. "Concluding remarks: progress toward the design of solid catalysts." Faraday Discussions 188 (2016): 591–602. http://dx.doi.org/10.1039/c6fd00134c.

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The 2016 Faraday Discussion on the topic “Designing New Heterogeneous Catalysts” brought together a group of scientists and engineers to address forefront topics in catalysis and the challenge of catalyst design—which is daunting because of the intrinsic non-uniformity of the surfaces of catalytic materials. “Catalyst design” has taken on a pragmatic meaning which implies the discovery of new and better catalysts on the basis of fundamental understanding of the catalyst structure and performance. The presentations and discussion at the meeting illustrate the rapid progress in this understanding linked with improvements in spectroscopy, microscopy, theory, and catalyst performance testing. The following text includes a statement of recurrent themes in the discussion and examples of forefront science that evidences progress toward catalyst design.

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Meng, Xiang, Hiroaki Suzuki, Kenta Sasaki, and Hirokazu Tatsuoka. "Characteristic Modification of Catalysts by Use of a Chloride Source." Solid State Phenomena 247 (March 2016): 106–10. http://dx.doi.org/10.4028/www.scientific.net/ssp.247.106.

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Structural control and morphological modification of a series of Si-based nanostructures were studied from the viewpoint of modifying the catalyst’s characteristics. The catalyst was modified from a liquid to a solid during its growth. The growth evolution of the faceted Si nanowires occurred via a vapor–liquid–solid mechanism followed by a silicide vapor–solid–solid mechanism. The shapes of the catalysts defined the shapes of the nanowires during the vapor–solid–solid growth. The catalyst was further modified by the deposition of MnCl2. Only irregularly shaped Si particles or MnCl2 particles were observed on top of the Si nanowires. The characteristic modification of catalysts by liquid-phase crystal nucleation and deposition of liquid-phase droplets was discussed. In addition, the synthesis of a CrSi2 nanowire bundle by the formation of dense nanoparticles was studied.

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Temu, A. K. "Biodiesel Production Using Mixed Solid Catalysts." Advanced Materials Research 824 (September 2013): 451–58. http://dx.doi.org/10.4028/www.scientific.net/amr.824.451.

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One of the disadvantages of homogeneous base catalysts in biodiesel production is that they cannot be reused or regenerated because they are consumed in the reaction. Besides, homogeneous catalysed process is not environmentally friendly because a lot of waste water is produced in the separation step. Unlike homogeneous, heterogeneous catalysts are environmentally benign, can be reused and regenerated, and could be operated in continuous processes, thus providing a promising option for biodiesel production. This paper presents catalytic activity of single and mixed solid catalysts in production of biodiesel from palm oil using methanol as well as ethanol at atmospheric pressure. The catalysts used are CaO, K2CO3, Al2O3, and CaO/K2CO3, CaO/Al2O3, K2CO3/Al2O3 mixtures. Results show that methanol is a better reactant with biodiesel yield ranging from 48 to 96.5% while ethanol gives yields ranging from 20 to 95.2%. The yield data for single catalysts range from 20 to 89.2% while that for mixed catalysts range from 52 to 96.5% indicating improvement in the activity by mixing the catalysts. The study also shows that biodiesel yield increases with catalyst loading which emphasizes the need for sufficient number of active sites. The properties of biodiesel produced compares well with ASTM D6751 and EN 14124 biodiesel standards.

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Hidayati, Nur, Rahmah Puspita Sari, and Herry Purnama. "Catalysis of glycerol acetylation on solid acid catalyst: a review." Jurnal Kimia Sains dan Aplikasi 23, no. 12 (January 14, 2021): 414–23. http://dx.doi.org/10.14710/jksa.23.12.414-423.

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Biodiesel is a substitute fuel that is environmentally friendly, biodegradable, and sustainable. The need for biodiesel continues to increase. Biodiesel is made through the process of transesterification of triglycerides and alcohol. Glycerol is a side-effect of biodiesel products with a capacity of 10% of the total weight of its production. Glycerol is the simplest glyceride compound and has several functions as a primary ingredient in chemical production. Through acetylation, glycerol is converted to a material that has a higher sale value. Both homogeneous and heterogeneous catalysts are the acetylation approach to achieve the desired product, namely acetyl glycerol esters (mono-, di- and triacetin). However, in the process, the catalyst’s type and characteristics significantly affect the yield and conversion of the product and the deactivation or reusability of the catalyst, which can inhibit the catalyst’s utilization and effectiveness; therefore, it must be studied further. Besides, the parameters that affect the reaction will also be assessed.

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Tyufekchiev, Maksim, Jordan Finzel, Ziyang Zhang, Wenwen Yao, Stephanie Sontgerath, Christopher Skangos, Pu Duan, Klaus Schmidt-Rohr, and Michael T. Timko. "A New Method for Solid Acid Catalyst Evaluation for Cellulose Hydrolysis." Sustainable Chemistry 2, no. 4 (November 15, 2021): 645–69. http://dx.doi.org/10.3390/suschem2040036.

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A systematic and structure-agnostic method for identifying heterogeneous activity of solid acids for catalyzing cellulose hydrolysis is presented. The basis of the method is preparation of a supernatant liquid by exposing the solid acid to reaction conditions and subsequent use of the supernatant liquid as a cellulose hydrolysis catalyst to determine the effects of in situ generated homogeneous acid species. The method was applied to representative solid acid catalysts, including polymer-based, carbonaceous, inorganic, and bifunctional materials. In all cases, supernatant liquids produced from these catalysts exhibited catalytic activity for cellulose hydrolysis. Direct comparison of the activity of the solid acid catalysts and their supernatants could not provide unambiguous detection of heterogeneous catalysis. A reaction pathway kinetic model was used to evaluate potential false-negative interpretation of the supernatant liquid test and to differentiate heterogeneous from homogeneous effects on cellulose hydrolysis. Lastly, differences in the supernatant liquids obtained in the presence and absence of cellulose were evaluated to understand possibility of false-positive interpretation, using structural evidence from the used catalysts to gain a fresh understanding of reactant–catalyst interactions. While many solid acid catalysts have been proposed for cellulose hydrolysis, to our knowledge, this is the first effort to attempt to differentiate the effects of heterogeneous and homogeneous activities. The resulting supernatant liquid method should be used in all future attempts to design and develop solid acids for cellulose hydrolysis.

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Shi, Chunjie, Xiaofeng Yu, Wei Wang, Haibing Wu, Ai Zhang, and Shengjin Liu. "The Activity and Cyclic Catalysis of Synthesized Iron-Supported Zr/Ti Solid Acid Catalysts in Methyl Benzoate Compounds." Catalysts 13, no. 6 (June 2, 2023): 971. http://dx.doi.org/10.3390/catal13060971.

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The catalytic activity and cyclic catalysis of different methyl benzoates were studied by using a series of Lewis solid acid catalysts. The iron-supported zirconium/titanium solid acid catalysts were characterized using FTIR, SEM, XRD, and BET. The details of catalytic activity and cyclic catalysis verified that the catalyst catalyzed the reactions of 31 benzoic acids with different substituents and methanol. In addition, the mechanism was revealed according to the microstructure, acid strength, and specific surface area of the catalysts, and the yields of methyl benzoates by the GC-MS. Zr ions had significant effects on the catalytic activity of the catalyst. A certain proportion of Fe and Ti ions additionally enhanced the catalytic activity of the catalyst, with the catalyst-specific composition of Fe:Zr: Ti = 2:1: 1 showing optimal catalytic activity. A variety of substituents in the benzene ring, such as the electron-withdrawing group, the electron-donating group, large steric hindrance, and the position of the group on the benzene ring, had regular effects on the catalytic activity of the methyl benzoates. An increase in the catalyst activity occurred owing to the increases in the catalyst surface and the number of acid sites after the Fe ion was added. The catalytic activity remained unchanged after the facile recycling method was performed.

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Manayil, Jinesh, Adam Lee, and Karen Wilson. "Functionalized Periodic Mesoporous Organosilicas: Tunable Hydrophobic Solid Acids for Biomass Conversion." Molecules 24, no. 2 (January 10, 2019): 239. http://dx.doi.org/10.3390/molecules24020239.

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The catalytic deoxygenation of bio-based feedstocks to fuels and chemicals presents new challenges to the catalytic scientist, with many transformations either performed in or liberating water as a byproduct during reaction. The design of catalysts with tunable hydrophobicity to aid product and reactant adsorption or desorption, respectively, is vital for processes including (trans)esterification and condensation reactions employed in sustainable biodiesel production and bio-oil upgrading processes. Increasing surface hydrophobicity of catalyst materials offers a means to displace water from the catalyst active site, and minimizes potential deactivation or hydrolysis side reactions. Hybrid organic–inorganic porous solids offer exciting opportunities to tune surface polarity and hydrophobicity, as well as critical parameters in controlling adsorption, reactant activation, and product selectivity in liquid and vapor phase catalysis. Here, we review advances in the synthesis and application of sulfonic-acid-functionalized periodic mesoporous organosilicas (PMO) as tunable hydrophobic solid acid catalysts in reactions relevant to biorefining and biofuel production.

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Motokura, Ken, and Kyogo Maeda. "Recent Advances in Heterogeneous Ir Complex Catalysts for Aromatic C–H Borylation." Synthesis 53, no. 18 (April 9, 2021): 3227–34. http://dx.doi.org/10.1055/a-1478-6118.

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AbstractAromatic C–H borylation catalyzed by an Ir complex is among the most powerful methods for activating inert bonds. The products, i.e., arylboronic acids and their esters, are usable chemicals for the Suzuki–Miyaura cross-coupling reaction, and significant effort has been directed toward the development of homogeneous catalysis chemistry. In this short review, we present a recent overview of current heterogeneous Ir-complex catalyst developments for aromatic C–H borylation. Not only have Ir complexes been immobilized on support surfaces with phosphine and bipyridine ligands, but Ir complexes incorporated within solid materials have also been developed as highly active and reusable heterogeneous Ir catalysts. Their catalytic activities and stabilities strongly depend on their surface structures, including linker length and ligand structure.1 Introduction and Homogeneous Ir Catalysis2 Heterogeneous Ir Complex Catalysts for C–H Borylation Reactions3 Other Heterogeneous Metal Complex Catalysts for C–H Borylation Reactions4 Summary and Outlook

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Testa, Maria Luisa, and Valeria La Parola. "Sulfonic Acid-Functionalized Inorganic Materials as Efficient Catalysts in Various Applications: A Minireview." Catalysts 11, no. 10 (September 23, 2021): 1143. http://dx.doi.org/10.3390/catal11101143.

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Acid catalysis is widely used in the chemical industry, and nowadays many efforts are being focused on replacing the more common homogeneous catalysts with heterogeneous ones in order to make greener the industrial processes. In this perspective, sulfonic solid acid materials represent a valid alternative to the homogenous mineral acid in several acid catalyzed reactions. In this minireview, an overview of the recent advances on the preparation, stability and application of these materials is reported. Special attention is addressed to the sustainability of the considered processes, starting from the catalyst’s preparation, the use of green solvents and reducing the possible reaction steps. Ways to tackle the main drawback represented by easy leaching of acid groups are described. For an easy catalyst recovery, the use of a magnetic core in a catalyst particle, with the related synthetic approaches, is also illustrated. Finally, a section is dedicated to the principal characterization techniques to identify the structural properties of the catalysts.

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Gai, Pratibha L., and Michael W. Anderson. "Solid catalysts and porous solids." Current Opinion in Solid State and Materials Science 5, no. 5 (October 2001): 363–64. http://dx.doi.org/10.1016/s1359-0286(01)00033-x.

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Gai, Pratibha L., and Michael W. Anderson. "Solid catalysts and porous solids." Current Opinion in Solid State and Materials Science 6, no. 5 (October 2002): 379. http://dx.doi.org/10.1016/s1359-0286(02)00121-3.

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Davis, MarkE, and IanE Maxwell. "Solid catalysts and porous solids." Current Opinion in Solid State and Materials Science 1, no. 1 (February 1996): 55–56. http://dx.doi.org/10.1016/s1359-0286(96)80010-6.

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Zones, Stacey, and Ian E. Maxwell. "Solid catalysts and porous solids." Current Opinion in Solid State and Materials Science 2, no. 1 (February 1997): 55–56. http://dx.doi.org/10.1016/s1359-0286(97)80105-2.

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Cheetham, Anthony K., and Sir John Meurig Thomas. "Solid catalysts and porous solids." Current Opinion in Solid State and Materials Science 3, no. 1 (February 1998): 61–62. http://dx.doi.org/10.1016/s1359-0286(98)80066-1.

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Anderson, Michael W. "Solid catalysts and porous solids." Current Opinion in Solid State and Materials Science 7, no. 3 (June 2003): 189. http://dx.doi.org/10.1016/j.cossms.2003.10.002.

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Anderson, M. W. "Solid Catalysts and Porous Solids." Current Opinion in Solid State and Materials Science 8, no. 6 (December 2004): 396. http://dx.doi.org/10.1016/j.cossms.2005.05.001.

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Mardina, Primata, Hesti Wijayanti, Abubakar Tuhuloula, Erita Hijriyati, and Sarifah. "Corncob residue as heterogeneous acid catalyst for green synthesis of biodiesel: A short review." Communications in Science and Technology 6, no. 2 (December 31, 2021): 60–68. http://dx.doi.org/10.21924/cst.6.2.2021.460.

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The utilization of an appropriate catalyst in biodiesel production depends on the free fatty acid content of vegetable oil as a feedstock. Recently, heterogeneous acid catalysts are widely chosen for biodiesel production. However, these catalysts are non-renewable, highly expensive and low stability. Due to the aforementioned drawbacks of commercial heterogeneous acid catalyst, a number of efforts have been made to develop renewable green solid acid catalysts derived from biomass. Published literature revealed that the application of the biomass derived solid acid catalysts can achieve up to 98% yield of biodiesel. This article focused on corncob as raw material in solid acid catalyst preparation for biodiesel production. The efficient preparation method and performance comparation are discussed here. The corncob derived heterogeneous acid catalysts provides an environmentally friendly and green synthesis for biodiesel production.

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Miceli, Mariachiara, Patrizia Frontera, Anastasia Macario, and Angela Malara. "Recovery/Reuse of Heterogeneous Supported Spent Catalysts." Catalysts 11, no. 5 (May 1, 2021): 591. http://dx.doi.org/10.3390/catal11050591.

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The rapid separation and efficient recycling of catalysts after a catalytic reaction are considered important requirements along with the high catalytic performances. In this view, although heterogeneous catalysis is generally less efficient if compared to the homogeneous type, it is generally preferred since it benefits from the easy recovery of the catalyst. Recycling of heterogeneous catalysts using traditional methods of separation such as extraction, filtration, vacuum distillation, or centrifugation is tedious and time-consuming. They are uneconomic processes and, hence, they cannot be carried out in the industrial scale. For these limitations, today, the research is devoted to the development of new methods that allow a good separation and recycling of catalysts. The separation process should follow a procedure economically and technically feasible with a minimal loss of the solid catalyst. The aim of this work is to provide an overview about the current trends in the methods of separation/recycling used in the heterogeneous catalysis.

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Kiss, Ernő, and Goran Boskovic. "Impeded solid state reactions and transformations in ceramic catalysts supports and catalysts." Processing and Application of Ceramics 6, no. 4 (2012): 173–82. http://dx.doi.org/10.2298/pac1204173k.

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Impeded chemical reactions and impeded polymorphous transformation in materials are discussed, as desired effects, for stabilization of ceramic catalyst supports and ceramic based catalysts. This paper gives a short overview about the possibilities of slowing down the aging processes in ceramic catalyst supports and catalysts. Special attention is given to alumina and titania based catalysts.

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Pierre, Alain C. "Aerogel Catalysts." Advances in Science and Technology 65 (October 2010): 174–83. http://dx.doi.org/10.4028/www.scientific.net/ast.65.174.

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Aerogels are often largely mesoporous solids, with a porosity which may exceed 90 vol% and a specific surface area up to 1000 m2 g-1. Such materials were first obtained by Kistler in 1932, and designate gels in which the liquid was replaced with a gas without collapsing the gel solid network. Contrary to xerogels dried from wet gels by evaporation with an important shrinkage, the first aerogels were obtained by a “supercritical drying” technique in which the liquid which impregnated the gels was evacuated after being transformed to a supercritical fluid. The diversity in nature of the solid constituting the rigid network is very large. It includes simple oxides, multi oxide compositions, organic and hybrid organic-inorganic polymers and carbon. This diversity as well as the high specific pore volume and surface area make aerogels applicable either as catalysts or as catalyst supports. Besides, molecular catalysts such as transition metal complexes or enzymes can easily be immobilized in aerogels, which opened the road to new supported molecular catalysts and biocatalysts. This communication reviews the synthesis and properties of oxide aerogel catalysts.

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Ertl, Gerhard, Maria Zielińska, Małgorzata Rajfur, and Maria Wacławek. "Elementary steps in heterogeneous catalysis: The basis for environmental chemistry." Chemistry-Didactics-Ecology-Metrology 22, no. 1-2 (December 1, 2017): 11–41. http://dx.doi.org/10.1515/cdem-2017-0001.

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Abstract Catalysis is an alternative way for reaching an immediate formation of a product, because of a lower energy barrier (between the molecules and the catalysts). Heterogeneous catalysis comprises the acceleration of a chemical reaction through interaction of the molecules involved with the surface of a solid. It is a discipline, which involves all the different aspects of chemistry: inorganic and analytical chemistry in order to characterize the catalysts and the forms of these catalysts. The industrial chemistry puts all these things together to understand the solid chemical handling, chemical reaction and energy engineering and the heat and mass transfer in these catalytic processes. Very often there are more than one, but several products, then the role of the catalyst is not so much related to activity, but to selectivity. The underlying elementary steps can now be investigated down to the atomic scale as will be illustrated mainly with two examples: the oxidation of carbon monoxide (car exhaust catalyst) and the synthesis of ammonia (the basis for nitrogen fertilizer). There is a huge market for the catalysts themselves despite of their high costs. A large fraction is used for petroleum refineries, automotive and industrial cleaning processes. The catalytic processes is a wide field and there are still many problems concerning energy conservation and energy transformation, so there is much to do in the future.

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WANG, C., Y. H. HE, L. Z. HOU, S. L. WANG, X. L. LIU, Q. ZHANG, and C. Q. PENG. "CATALYTIC SYNTHESIS AND GROWTH MECHANISM OF TUNGSTEN NANOWIRE ARRAYS ON SIO2 SUBSTRATES." Nano 08, no. 01 (February 2013): 1350010. http://dx.doi.org/10.1142/s1793292013500100.

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Single-crystalline W nanowires, with approximately 150 nm in diameter and 15 μm in length, have been successfully synthesized on SiO2 substrates by chemical vapor deposition (CVD) with the assistance of Ni catalysts at 950°C. The catalysts located at the tip of W nanowires were found to be Ni4W in a solid state, rather than a liquid state. The low-temperature growth of W nanowires using the solid catalysts can be generally accessible, provided that the appropriate combination of solid catalysts and nanowires are thermodynamically available, thus suggesting the implication for the potentially large-area integrated growth on various substrates. The growth direction of the generated [100]-oriented W nanowires was presumed to be determined by the orientation relationship between the solid Ni catalyst particle and the W precipitate. A possible catalytic growth model was proposed according to the analysis of the experimental results. The orientation relationship between the solid catalyst particle and the corresponding nanowire was expected to be also valid for some other nanowires induced by solid catalyst.

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Chowdhry, Uma, MA Subramanian, and Rutger A. van Santen. "Solid catalysts and porous solids hot topics in heterogeneous catalysis." Current Opinion in Solid State and Materials Science 4, no. 1 (February 1999): 53–54. http://dx.doi.org/10.1016/s1359-0286(99)80011-4.

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AlMohamadi, Hamad, Abdulrahman Aljabri, Essam R. I. Mahmoud, Sohaib Z. Khan, Meshal S. Aljohani, and Rashid Shamsuddin. "Catalytic Pyrolysis of Municipal Solid Waste: Effects of Pyrolysis Parameters." Bulletin of Chemical Reaction Engineering & Catalysis 16, no. 2 (March 17, 2021): 342–52. http://dx.doi.org/10.9767/bcrec.16.2.10499.342-352.

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Burning municipal solid waste (MSW) increases CO2, CH4, and SO2 emissions, leading to an increase in global warming, encouraging governments and researchers to search for alternatives. The pyrolysis process converts MSW to oil, gas, and char. This study investigated catalytic and noncatalytic pyrolysis of MSW to produce oil using MgO-based catalysts. The reaction temperature, catalyst loading, and catalyst support were evaluated. Magnesium oxide was supported on active carbon (AC) and Al2O3 to assess the role of support in MgO catalyst activity. The liquid yields varied from 30 to 54 wt% based on the experimental conditions. For the noncatalytic pyrolysis experiment, the highest liquid yield was 54 wt% at 500 °C. The results revealed that adding MgO, MgO/Al2O3, and MgO/AC declines the liquid yield and increases the gas yield. The catalysts exhibited significant deoxygenation activity, which enhances the quality of the pyrolysis oil and increases the heating value of the bio-oil. Of the catalysts that had high deoxygenation activity, MgO/AC had the highest relative yield. The loading of MgO/AC varied from 5 to 30 wt% of feed to the pyrolysis reactor. As the catalyst load increases, the liquid yield declines, while the gas and char yields increase. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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Jiang, Qimeng, Guihua Yang, Fangong Kong, Pedram Fatehi, and Xiaoying Wang. "High Acid Biochar-Based Solid Acid Catalyst from Corn Stalk for Lignin Hydrothermal Degradation." Polymers 12, no. 7 (July 21, 2020): 1623. http://dx.doi.org/10.3390/polym12071623.

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Solid acid catalysts generally show the disadvantage of low acid amount and low recycling rate. To solve these problems, corn stalk-based solid acid catalysts were synthesized through carbonization and sulfonation processes in this work. The results showed that besides the rod-like structure inherited from raw corn stalk, the catalysts contained some small broken pieces on the surface, and the specific surface area varied from 1120 to 1640 m2/g. The functional groups (-SO3H) were successfully introduced onto the surface of the obtained solid acid catalysts. The acid amount varied between 1.2 and 2.4 mmol/g, which was higher than most of solid acid catalysts. The catalyst produced at 800 °C for 6 h in carbonation and then at 150 °C for 8 h in sulfonation had larger specific surface area and more sulfonate groups. In the degradation of lignin, the use of catalyst led to the generation of more aromatic compounds (65.6 wt. %) compared to that without using the catalyst (40.5 wt. %). In addition, a stable yield of reaction (85%) was obtained after four reuses. Therefore, corn stalk is suitable for high-value utilization to prepare high-acid amount biochar-based catalyst.

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Quevedo, Rodolfo, Camilo Perdomo, and Sonia Moreno. "Heterogeneous Catalysts in Pictet-Spengler-Type Reactions." Journal of Chemistry 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/125302.

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Several solid catalysts were evaluated as an alternative for 1,2,3,4-tetrahydroisoquinoline synthesis by means of the Pictet-Spengler reaction. The reaction catalysed by a mixed oxide (Mg and Al) led to the best yield and good regioselectivity; using an Al-pillared bentonite led to good yields and total regioselectivity. The results revealed no direct relationship between catalyst acidity and yield.

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Abedin, Md Ashraful, Swarom Kanitkar, Nitin Kumar, Zi Wang, Kunlun Ding, Graham Hutchings, and James J. Spivey. "Probing the Surface Acidity of Supported Aluminum Bromide Catalysts." Catalysts 10, no. 8 (August 3, 2020): 869. http://dx.doi.org/10.3390/catal10080869.

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Solid acid catalysis is an important class of reactions. The principal advantages of solid acid catalysts as compared to their corresponding fluid acids include minimal waste and ease of product separation. One type of these catalysts is based on aluminum bromide (Al2Br6), which is a stronger Lewis acid than Al2Cl6. In this report, Al2Br6 is grafted on commercial mesoporous silica (CMS), SBA-15 and silica gel to create a solid catalyst similar to the silica-supported Al2Cl6 superacid. These supported Al2Br6 catalysts were characterized by NH3-Temperature Programmed Desorption (TPD), pyridine Diffuse Reflectance for Infrared Fourier Transform Spectroscopy (DRIFTS) and Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR). Formation of acid sites was confirmed and quantified with NH3-TPD. Both Lewis and Brønsted sites were observed with DRIFTS using pyridine as a probe molecule. In addition, thermal stability of acid sites was also studied using DRIFTS. 27Al MAS NMR analysis showed tetrahedral, pentahedral and octahedral co-ordination of Al, confirming that Al2Br6 reacted with –OH groups on silica surface. Performance of these catalysts was evaluated using acid-catalyzed 1-butene isomerization. Conversion above 80% was observed at 200 °C, corresponding to thermodynamic equilibrium.

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Liu, Yun, Zong Ming Zheng, and Jin Qi Zhu. "Experimental Study on Cellulose Hydrolysis Using Active Carbon-Based and Carbon Nanotube-Based Solid Acid Catalysts." Advanced Materials Research 953-954 (June 2014): 178–82. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.178.

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Three kinds of carbon-based solid acid catalysts were prepared to hydrolyze cellulose with activated carbon (AC) and multi-walled carbon nanotubes (MWCNTs) as the carrier. The prepared solid acid catalysts were characterized by BET, SEM, XRD, FTIR and TG analysis. The catalytic activities of these prepared solid acid catalysts for heterogeneously catalyzed hydrolysis of microcrystalline cellulose were further investigated. The catalysts bearing hydroxyl, carboxyl and sulfonic groups is thermally stable. Due to the amorphous multi-layered structure and the large number of defected structure, AC-based solid acid bears more acid groups than the MWCNTs-based catalyst. which hence showing higher activity for the catalytic hydrolysis of cellulose. AC-based solid acid exihibited two-fold higher catalytic efficiency than that of the MWCNTs-based solid acid catalysts.

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Said, Abd El-Aziz Ahmed. "Physicochemical and Catalytic Properties of Spinels Formed by Solid-Solid Interaction Between Fe2O3and V2O5." Collection of Czechoslovak Chemical Communications 61, no. 8 (1996): 1131–40. http://dx.doi.org/10.1135/cccc19961131.

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Vanadium oxide catalysts doped or mixed with 1-50 mole % Fe3+ ions were prepared. The structure of the original samples and those calcined from 200 up to 500 °C were characterized by TG, DTA, IR and X-ray diffraction. The SBET values and texture of the solid catalysts were investigated. The catalytic dehydration-dehydrogenation of isopropanol was carried out at 200 °C using a flow system. The results obtained showed an observable decrease in the activity of V2O5 on the addition of Fe3+ ions. Moreover, Fe2V4O13 is the more active and selective catalyst than FeVO4 spinels. The results were correlated with the active sites created on the catalyst surface.

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Wilson, Karen, and James H. Clark. "Solid acids and their use as environmentally friendly catalysts in organic synthesis." Pure and Applied Chemistry 72, no. 7 (January 1, 2000): 1313–19. http://dx.doi.org/10.1351/pac200072071313.

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Tightening environmental legislation is driving the fine and speciality chemicals industries to consider alternative processes that avoid the use of conventional mineral acids. The use of heterogeneous catalysts in these processes would vastly simplify catalyst removal, minimizing the amount of waste formed. However, diffusion limitation of liquids within porous solids dictates that effective solid acids for liquid-phase reactions require the use of mesoporous materials <20_100Å. Recent developments in materials chemistry has led to the discovery of a family of ordered mesoporous silicas which opens up new possibilities for preparing solid-acid catalysts for liquid-phase reactions. This review concentrates on recent developments in the synthesis of new mesoporous solid acids for liquid-phase organic synthesis.

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Sheldon, Roger A. "Homogeneous catalysts to solid catalysts." Current Opinion in Solid State and Materials Science 1, no. 1 (February 1996): 101–6. http://dx.doi.org/10.1016/s1359-0286(96)80017-9.

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Lindner, J., A. Sachdev, M. A. Villa-Garcia, and J. Schwank. "A high resolution and Analytical Electron Microscopy study of novel solid state hydrodesulfurization catalysts." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 264–65. http://dx.doi.org/10.1017/s0424820100153294.

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The removal of sulfur from petroleum feedstocks is of great importance to the oil industry. The process, known as hydrodesulfurization (HDS), is typically catalyzed by Group VIB metal oxides. The workhorse of the industry today is an alumina supported CoO-MoO3 catalyst. Recently, several models have been proposed for the active site responsible for HDS activity, but despite extensive research efforts there is still no clear relationship between structure and activity. We have prepared promoted and non-stoichiometric catalyst samples via a novel solid state synthesis route. These catalysts are not only quite active in the HDS of thiophene, but are also more thermally stable and consequently easier to characterize than the standard HDS materials prepared by wet chemistry methods. Most studies on HDS catalysts rely on bulk techniques for characterization analysis, however, these do not provide any information at the microscopic level where catalysis occurs. For that reason we have used analytical and high resolution electron microscopy to obtain information at the atomic level, coupled with bulk techniques such as x-ray diffraction and surface area measurements. The objective was to develop a link between the microstructure of our solid state catalysts and their HDS activity.

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Baráth, Eszter. "Selective Reduction of Carbonyl Compounds via (Asymmetric) Transfer Hydrogenation on Heterogeneous Catalysts." Synthesis 52, no. 04 (January 2, 2020): 504–20. http://dx.doi.org/10.1055/s-0039-1691542.

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Based on the ever-increasing demand for optically pure compounds, the development of efficient methods to produce such products is very important. Homogeneous asymmetric catalysis occupies a prominent position in the ranking of chemical transformations, with transition metals coordinated to chiral ligands being applied extensively for this purpose. However, heterogeneous catalysts have the ability to further extend the field of asymmetric transformations, because of their beneficial properties such as high stability, ease of separation and regeneration, and the possibility to apply them in continuous processes. The main challenge is to find potential synthetic routes that can provide a chemically and thermally stable heterogeneous catalyst having the necessary chiral information, whilst keeping the catalytic activity and enantioselectivity equally high (or even higher) than the corresponding homogeneous counterpart. Within this short review, the most relevant immobilization modes and preparative strategies depending on the support material used are summarized. From the reaction scope viewpoint, metal catalysts supported on the various solid materials studied in (asymmetric) transfer hydrogenation of carbonyl compounds are selected and represent the main focus of the second part of this overview.1 Introduction2 Synthesis of Chiral Heterogeneous Catalysts2.1 Immobilization of Homogeneous Asymmetric Catalysts2.1.1 Immobilization on Inorganic Supports2.1.2 Immobilization on Organic Polymers as Supports2.1.3 Immobilization on Dendrimer-Type Materials as Supports2.1.4 Self-Supported Chiral Catalysts: Coordination Polymers2.1.5 Immobilization Using Non-Conventional Media2.2 Chirally Modified Metal Surfaces for Heterogeneous Asymmetric Catalysis3 Examples of Transfer Hydrogenation on Heterogeneous Catalysts3.1 Silicon-Immobilized Catalysts3.2 Carbon-Material-Immobilized Catalysts3.3 Polymer-Immobilized Catalysts3.4 Magnetic-Nanoparticle-Immobilized Catalysts4 Conclusions

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Vasić, Katja, Gordana Hojnik Podrepšek, Željko Knez, and Maja Leitgeb. "Biodiesel Production Using Solid Acid Catalysts Based on Metal Oxides." Catalysts 10, no. 2 (February 17, 2020): 237. http://dx.doi.org/10.3390/catal10020237.

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The development of solid acid catalysts, especially based on metal oxides and different magnetic nanoparticles, gained much awareness recently as a result of the development of different nano-based materials. Solid acid catalysts based on metal oxides are promising for the (trans)esterification reactions of different oils and waste materials for biodiesel production. This review gives a brief overview of recent developments in various solid acid catalysts based on different metal oxides, such as zirconia, zinc, titanium, iron, tungsten, and magnetic materials, where the catalysts are optimized for various reaction parameters, such as the amount of catalyst, molar ratio of oil to alcohol, reaction time, and temperature. Furthermore, yields and conversions for biodiesel production are compared. Such metal-oxide-based solid acid catalysts provide more sustainable, green, and easy-separation synthesis routes with high catalytic activity and reusability than traditionally used catalysts.

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Ansanay, Yane, Praveen Kolar, Ratna Sharma-Shivappa, Jay Cheng, Sunkyu Park, and Consuelo Arellano. "Pre-treatment of biomasses using magnetised sulfonic acid catalysts." Journal of Agricultural Engineering 48, no. 2 (June 1, 2017): 117. http://dx.doi.org/10.4081/jae.2017.594.

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There is a significant interest in employing solid acid catalysts for pre-treatment of biomasses for subsequent hydrolysis into sugars, because solid acid catalysts facilitate reusability, high activity, and easier separation. Hence the present research investigated pretreatment of four lignocellulosic biomasses, namely Switchgrass (Panicum virgatum L ‘Alamo’), Gamagrass (Tripsacum dactyloides), Miscanthus (Miscanthus × giganteus) and Triticale hay (Triticale hexaploide Lart.) at 90°C for 2 h using three carbon-supported sulfonic acid catalysts. The catalysts were synthesized via impregnating p-Toluenesulfonic acid on carbon (regular) and further impregnated with iron nitrate via two methods to obtain magnetic A and magnetic B catalysts. When tested as pre-treatment agents, a maximum total lignin reduction of 17.73±0.63% was observed for Triticale hay treated with magnetic A catalyst. Furthermore, maximum glucose yield after enzymatic hydrolysis was observed to be 203.47±5.09 mg g–1 (conversion of 65.07±1.63%) from Switchgrass treated with magnetic A catalyst. When reusability of magnetised catalysts were tested, it was observed that magnetic A catalyst was consistent for Gamagrass, Miscanthus × Giganteus and Triticale hay, while magnetic B catalyst was found to maintain consistent yield for switchgrass feedstock. Our results suggested that magnetised solid acid catalyst could pre-treat various biomass stocks and also can potentially reduce the use of harsh chemicals and make bioenergy processes environment friendly.

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Takabatake, Moe, and Ken Motokura. "Montmorillonite-based heterogeneous catalysts for efficient organic reactions." Nano Express 3, no. 1 (March 1, 2022): 014004. http://dx.doi.org/10.1088/2632-959x/ac5ac3.

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Abstract In this review, we give a brief overview of recently developed montmorillonite-based heterogeneous catalysts used for efficient organic reactions. Cation-exchanged montmorillonite catalysts, metal catalysts supported on montmorillonite, and an interlayer design used for selective catalysis are introduced and discussed. In traditional syntheses, homogeneous acids and metal salts were used as catalysts, but the difficulty in separation of catalysts from products was a bottleneck when considering industrialization. The use of solid heterogeneous catalysts is one of the major solutions to overcome this problem. Montmorillonite can be used as a heterogeneous catalyst and/or catalyst support. This clay material exhibits strong acidity and a stabilizing effect on active species, such as metal nanoparticles, due to its unique layered structure. These advantages have led to the development of montmorillonite-based heterogeneous catalysts. Acidic montmorillonite, such as proton-exchanged montmorillonite, exhibits a high catalytic activity for the activation of electrophiles, such as alcohols, alkenes, and even alkanes. The montmorillonite interlayer/surface also functions as a good support for various metal species used for oxidation and carbon-carbon bond forming reactions. The use of an interlayer structure enables selective reactions and the stabilization of catalytically active species.

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Chadwick, F. Mark, Alasdair I. McKay, Antonio J. Martinez-Martinez, Nicholas H. Rees, Tobias Krämer, Stuart A. Macgregor, and Andrew S. Weller. "Solid-state molecular organometallic chemistry. Single-crystal to single-crystal reactivity and catalysis with light hydrocarbon substrates." Chemical Science 8, no. 9 (2017): 6014–29. http://dx.doi.org/10.1039/c7sc01491k.

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Kingkam, Wilasinee, Jirapa Maisomboon, Khemmanich Khamenkit, Sasikarn Nuchdang, Kewalee Nilgumhang, Sudarat Issarapanacheewin, and Dussadee Rattanaphra. "Preparation of CaO@CeO2 Solid Base Catalysts Used for Biodiesel Production." Catalysts 14, no. 4 (April 4, 2024): 240. http://dx.doi.org/10.3390/catal14040240.

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The study investigated the use of CeO2 extracted from monazite with calcium oxide (CaO) as a solid catalyst for biodiesel production. The wet impregnation method was used to produce CaO@CeO2 mixed-oxide catalysts with 0–50 wt.% CaO. X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, thermogravimetric analysis (TGA), and a Fourier transform infrared spectrometer (FTIR) was used to characterize the catalysts. In order to determine the optimal preparation conditions, the effect of different CaO compositions on the performance of CaO@CeO2 mixed-oxide catalysts was examined. The catalytic activity of the CaO@CeO2 catalyst for the transesterification reaction of palm oil to produce biodiesel was studied. The results show that the optimum yield of biodiesel can reach 97% fatty acid methyl ester over the 30CaO@CeO2 catalyst at the reaction conditions of 5 wt.% catalysts, methanol-to-oil molar ratio of 9:1, with a reaction temperature of 65 °C within 30 min. The results show that the high catalytic activity and stability of the CaO@CeO2 catalyst make it a promising candidate for industrial-scale biodiesel production. Further study is needed to improve the stability and efficiency of catalysts in transesterification reactions to achieve a high FAME yield using long-life-span catalysts. Moreover, it is necessary to investigate the economic feasibility of this process for application in large-scale biodiesel production.

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Bulavchenko, Olga A., and Zakhar S. Vinokurov. "In Situ X-ray Diffraction as a Basic Tool to Study Oxide and Metal Oxide Catalysts." Catalysts 13, no. 11 (November 7, 2023): 1421. http://dx.doi.org/10.3390/catal13111421.

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X-ray diffraction (XRD) is a standard technique that is widely applied in heterogeneous catalysis to determine phase composition, atomic structure, and size of crystallites. This review is focused on the application of in situ XRD for studying the catalysts during their “lifetime” (under synthesis, activation, operation, and deactivation conditions), limiting the objects of research to oxide and metal oxide catalysts. Also included is a brief overview of modern techniques and instruments and the latest works illustrating different aspects of this technique in catalyst research. The main conclusion is that the field of heterogeneous catalysis research would benefit substantially from the application of in situ XRD for the structural, phase, and morphological characterization of solid catalysts. Even more useful information can be obtained if XRD is combined with other techniques that are more sensitive at length scales different from that of XRD.

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Chołuj, Artur, Wojciech Nogaś, Michał Patrzałek, Paweł Krzesiński, Michał J. Chmielewski, Anna Kajetanowicz, and Karol Grela. "Preparation of Ruthenium Olefin Metathesis Catalysts Immobilized on MOF, SBA-15, and 13X for Probing Heterogeneous Boomerang Effect." Catalysts 10, no. 4 (April 17, 2020): 438. http://dx.doi.org/10.3390/catal10040438.

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Promoted by homogeneous Ru-benzylidene complexes, the olefin metathesis reaction is a powerful methodology for C-C double bonds formation that can find a number of applications in green chemical production. A set of heterogeneous olefin metathesis pre-catalysts composed of ammonium-tagged Ru-benzylidene complexes 4 (commercial FixCat™ catalyst) and 6 (in-house made) immobilized on solid supports such as 13X zeolite, metal-organic framework (MOF), and SBA-15 silica were obtained and tested in catalysis. These hybrid materials were doped with various amounts of ammonium-tagged styrene derivative 5—a precursor of a spare benzylidene ligand—in order to enhance pre-catalyst regeneration via the so-called release-return “boomerang effect”. Although this effect was for the first time observed inside the solid support, we discovered that non-doped systems gave better results in terms of the resulting turnover number (TON) values, and the most productive were hybrid catalysts composed of 4@MOF, 4@SBA-15, and 6@SBA-15.

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Tang, Xiaolong, Xianmang Xu, Honghong Yi, Chen Chen, and Chuan Wang. "Recent Developments of Electrochemical Promotion of Catalysis in the Techniques of DeNOx." Scientific World Journal 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/463160.

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Electrochemical promotion of catalysis reactions (EPOC) is one of the most significant discoveries in the field of catalytic and environmental protection. The work presented in this paper focuses on the aspects of reaction mechanism, influencing factors, and recent positive results. It has been shown with more than 80 different catalytic systems that the catalytic activity and selectivity of conductive catalysts deposited on solid electrolytes can be altered in the last 30 years. The active ingredient of catalyst can be activated by applying constant voltage or constant current to the catalysts/electrolyte interface. The effect of EPOC can improve greatly the conversion rate of NOx. And it can also improve the lifetime of catalyst by inhibiting its poisoning.

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Ikenaga, Kazuhiro, Ayaka Hamada, Takahiro Inoue, and Katsuki Kusakabe. "Biodiesel Production Using Metal Oxide Catalysts under Microwave Heating." International Journal of Biomass and Renewables 6, no. 2 (December 29, 2017): 23. http://dx.doi.org/10.61762/ijbrvol6iss2art4448.

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Biodiesel has been commercially produced by transesterification of triglyceride with homogeneous base catalyst, where the separation of catalysts, glycerol and biodiesel from the product is troublesome. The solid catalyst can be used to resolve the separation problem and available to be reused. In this study metal oxide catalysts (PbO2, MnO2, Bi2O3, Fe3O4, TiO2, Fe2O3) were selected for the transesterification. Purity of fatty acid methyl ester (FAME) in the products, which is equivalent of FAME yield, was determined for these catalysts under pressurized microwave heating condition (200oC and 1.9 MPa). More than 89% of FAME purity was achieved with PbO2 and MnO2 catalyst for 30 minutes. Keywords: microwave, biodiesel, high pressure, solid catalyst, metal oxide

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Hidayati, Nur, Titik Pujiati, Elfrida B. Prihandini, and Herry Purnama. "Synthesis of Solid Acid Catalyst from Fly Ash for Eugenol Esterification." Bulletin of Chemical Reaction Engineering & Catalysis 14, no. 3 (December 1, 2019): 683. http://dx.doi.org/10.9767/bcrec.14.3.4254.683-688.

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A series of fly ash-based heterogeneous acid catalysts were prepared by chemical and thermal treatment. Fly ash was chemically activated using sulfuric acid and followed by thermal activation. Characterization methods of XRD, BET, SEM-EDX, and the performance in esterification of eugenyl acetate production was carried out to reveal the physical and chemical characteristics of prepared catalysts. Activated catalyst showed high silica content (96.5%) and high BET surface area of 70 m2.g-1. The catalyst was proven to be highly active solid acid catalyst for liquid phase esterification of eugenol with acetic acid yielding eugenyl acetate. A yield of 43-48% was obtained with activated fly ash catalysts for 90 minutes reaction. These catalysts may replace beneficially the conventional homogenous liquid acid to the eco-friendly heterogeneous one. Copyright © 2019 BCREC Group. All rights reserved

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Li, Boyu, Abhishek Raj, Eric Croiset, and John Z. Wen. "Reactive Fe-O-Ce Sites in Ceria Catalysts for Soot Oxidation." Catalysts 9, no. 10 (September 28, 2019): 815. http://dx.doi.org/10.3390/catal9100815.

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This study investigates the role of oxygen vacancy on Fe-doped CeO2 catalyst activity for soot oxidation. The oxygen vacancy was assessed through Ce3+ content. The Fe content was varied between 0 and 30% for two catalyst preparation methods, co-precipitation (CP) and solution combustion synthesis (SCS). X-ray photoelectron spectroscopy indicates that ceria exists as both Ce4+ and Ce3+, while iron is present only as Fe3+. The catalyst’s activity was evaluated by ignition (T10) and combustion (T50) temperatures using thermogravimetric analysis. Optimum Fe contents yielding the highest activity were found to be 10% and 5% for CP and SCS catalysts, respectively. The surface area and morphology showed a moderate effect on catalyst activity, because catalytic soot oxidation involves solid–solid contact. More importantly, regardless of the fabrication method, it was found that Ce3+ content, which is closely related to oxygen vacancies, plays the most important role in affecting the catalyst activity.

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Hu, Yun Hang, and Eli Ruckenstein. "Comment on “Dry reforming of methane by stable Ni–Mo nanocatalysts on single-crystalline MgO”." Science 368, no. 6492 (May 14, 2020): eabb5459. http://dx.doi.org/10.1126/science.abb5459.

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Song et al. (Reports, 14 February 2020, p. 777) ignore the reported efficient Ni/MgO solid-solution catalysts and overstate the novelty and importance of the Mo-doped Ni/MgO catalysts for the dry reforming of methane. We show that the Ni/MgO solid-solution catalyst that we reported in 1995, which is efficient and stable for the dry reforming, is superior to the Mo-doped Ni/MgO catalyst.

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Albano, Gianluigi, Antonella Petri, and Laura Antonella Aronica. "Palladium Supported on Bioinspired Materials as Catalysts for C–C Coupling Reactions." Catalysts 13, no. 1 (January 16, 2023): 210. http://dx.doi.org/10.3390/catal13010210.

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In recent years, the immobilization of palladium nanoparticles on solid supports to prepare active and stable catalytic systems has been deeply investigated. Compared to inorganic materials, naturally occurring organic solids are inexpensive, available and abundant. Moreover, the surface of these solids is fully covered by chelating groups which can stabilize the metal nanoparticles. In the present review, we have focused our attention on natural biomaterials-supported metal catalysts applied to the formation of C–C bonds by Mizoroki–Heck, Suzuki–Miyaura and Sonogashira reactions. A systematic approach based on the nature of the organic matrix will be followed: (i) metal catalysts supported on cellulose; (ii) metal catalysts supported on starch; (iii) metal catalysts supported on pectin; (iv) metal catalysts supported on agarose; (v) metal catalysts supported on chitosan; (vi) metal catalysts supported on proteins and enzymes. We will emphasize the effective heterogeneity and recyclability of each catalyst, specifying which studies were carried out to evaluate these aspects.

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Gai, Pratibha L., Edward D. Boyes, Stig Helveg, Poul L. Hansen, Suzanne Giorgio, and Claude R. Henry. "Atomic-Resolution Environmental Transmission Electron Microscopy for Probing Gas–Solid Reactions in Heterogeneous Catalysis." MRS Bulletin 32, no. 12 (December 2007): 1044–50. http://dx.doi.org/10.1557/mrs2007.214.

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AbstractAdvances in atomic-resolution environmental transmission electron microscopy (ETEM) and related techniques for probing gas–solid reactions in situ are described. The capabilities of ETEM allow the dynamic nanostructure of heterogeneous catalysts in their functioning states to be directly monitored in real time. Applications of ETEM in catalysis are outlined, and they illustrate significant new insights into the dynamic nanostructure of the catalyst materials and their modes of operation.

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Kaur, Mandeep, Opinder Kaur, Rahul Badru, Sandeep Kaushal, and Pritpal Singh. "Ionic Liquid Assisted C-C Bond Formation." Current Organic Chemistry 24, no. 16 (November 9, 2020): 1853–75. http://dx.doi.org/10.2174/1385272824999200801022221.

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With their ability to dissolve inorganic as well as organic materials, ionic liquids have emerged as a versatile solvent system for a diverse range of organic transformations. In the past few decades, the literature has witnessed remarkable advances in a wide range of organic conversions carried out in the presence of various imidazolium, pyridinium, pyrrolidinium, quinolinium and diazobicyclo-octane based ionic liquids. In the reaction, ionic liquids serve as a solvent, catalyst or sometimes both. In certain cases, they are also modified with metal nanoparticles or complexes to form heterogeneous catalysts or are immobilized onto solid support like agar-agar to act as solid-support catalysts. Reactions catalysed by ionic liquids incorporating chiral catalysts possess the advantageous features of being highly enantioselective and reproducible, besides being economical and easy to handle. In this review, an updated insight regarding the role played by ionic liquids in various C-C bond-forming organic reactions, has been summarized.

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Journal articles on the topic 'Solid Catalysts'

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