Bibliographies thématiques / The heterogeneous catalyst

Littérature scientifique sur le sujet « The heterogeneous catalyst »

Auteur : Grafiati
Publié le 18 mai 2024

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Articles de revues sur le sujet "The heterogeneous catalyst"

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Ma, Yubo, Zhixian Gao, Tao Yuan et Tianfu Wang. « Kinetics of Dicyclopentadiene Hydroformylation over Rh–SiO2 Catalysts ». Progress in Reaction Kinetics and Mechanism 42, no 2 (mai 2017) : 191–99. http://dx.doi.org/10.3184/146867817x14821527549013.

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The hydroformylation of dicyclopentadiene (DCPD) to monoformyltricyclodecenes (MFTD) represents a key intermediate step in the conversion of the C5 fraction derived from the petrochemical process to value-added fine chemicals, for example, diformyltricyclodecanes and tricyclodecanedimethylol. Although both heterogeneous and homogeneous catalysts can catalyse this reaction, the heterogeneously catalysed pathway has received significantly less attention due to its lower catalytic activities. We demonstrate in this work that a low Rh loaded heterogeneous 0.1% Rh–SiO2 catalyst can present a similar performance relative to the homogeneous Rh(PPh3)Cl, a reference catalyst for this reaction. Furthermore, an extensive kinetic study of DCPD hydroformylation to MFTD using heterogeneous 0.1% Rh–SiO2 catalysts has been performed. A series of kinetic experiments was carried out over a broad range of conditions (temperature: 100–120 °C; pressure: 1.5–5 MPa; catalyst-to-reactant mass ratio: 0.02–0.05; PPh3 concentration: 5–12.5 g L−1). A kinetic analysis was carried out, indicating the activation energy for the reaction to be 84.7 kJ mol−1. DCPD conversion and MFTD yield could be optimised to be as high as 99% at 0.1% Rh loading, a DCPD/catalyst mass ratio of 25, a PPh3 concentration of 10 g L−1, a reaction time of 4 h and a reaction pressure of 4 MPa.
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Lomic, Gizela, Erne Kis, Goran Boskovic et Radmila Marinkovic-Neducin. « Application of scanning electron microscopy in catalysis ». Acta Periodica Technologica, no 35 (2004) : 67–77. http://dx.doi.org/10.2298/apt0435067l.

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A short survey of various information obtained by scanning electron microscopy (SEM) in the investigation of heterogeneous catalysts and nano-structured materials have been presented. The capabilities of SEM analysis and its application in testing catalysts in different fields of heterogeneous catalysis are illustrated. The results encompass the proper way of catalyst preparation, the mechanism of catalyst active sites formation catalysts changes and catalyst degradation during their application in different chemical processes. Presented SEM pictures have been taken on a SEM JOEL ISM 35 over 25 years of studies in the field of heterogeneous catalysis.
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Khan, Haris Mahmood, Tanveer Iqbal, Saima Yasin, Muhammad Irfan, Muhammad Mujtaba Abbas, Ibham Veza, Manzoore Elahi M. Soudagar, Anas Abdelrahman et Md Abul Kalam. « Heterogeneous Catalyzed Biodiesel Production Using Cosolvent : A Mini Review ». Sustainability 14, no 9 (22 avril 2022) : 5062. http://dx.doi.org/10.3390/su14095062.

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Biodiesel is gaining recognition as a good replacement for typical diesel owing to its renewability, sustainability, and eco-friendly nature. Transesterification is the leading route for biodiesel generation, which occurs during homogeneous/heterogeneous/enzymatic catalysis. Besides this, the usage of heterogeneous catalysts is considered more advantageous over homogeneous catalysts due to the easy catalyst recovery. Consequently, numerous heterogeneous catalysts have been synthesized from multiple sources with the intention of making the manufacturing process more efficient and cost-effective. Alongside this, numerous researchers have attempted to improve the biodiesel yield using heterogeneous catalysts by introducing cosolvents, such that phase limitation between oil and alcohol can be minimized. This short review is aimed at examining the investigations performed to date on heterogeneously catalyzed biodiesel generation in the presence of different cosolvents. It encompasses the techniques for heterogeneous catalyst synthesis, reported in the literature available for heterogeneous catalyzed biodiesel generation using cosolvents and their effects. It also suggests that the application of cosolvent in heterogeneously catalyzed three-phase systems substantially reduces the mass transfer limitation between alcohol and oil phases, which leads to enhancements in biodiesel yield along with reductions in values of optimized parameters, with catalyst weight ranges from 1 to 15 wt. %, and alcohol/oil ratio ranges from 5.5 to 20. The reaction time for getting the maximum conversion ranges from 10 to 600 min in the presence of different cosolvents. Alongside this, most of the time, the biodiesel yield remained above 90% in the presence of cosolvents.
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Kaplunenko, Volodymyr, et Mykola Kosinov. « Electric field - induced catalysis. Laws of field catalysis ». InterConf, no 26(129) (18 octobre 2022) : 332–51. http://dx.doi.org/10.51582/interconf.19-20.10.2022.037.

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Abstract.The article explores a new type of catalysis - electric field catalysis. The laws of field catalysis are given. The characteristics of the electric field are determined, which set the values of the characteristics of the field catalysis. Field catalysis and field catalyst do not fit into the traditional definition of catalysis and catalyst, which may require a revision of the terminology of catalysis. The field is a more versatile catalyst compared to material catalysts, both in terms of its application to a wider range of chemical reactions, and in the ability to control the rate and selectivity. It is shown that a common donor-acceptor mechanism of catalysis is realized in heterogeneous and field catalysis. Generalized formulas are obtained, from which, as partial results, the laws of heterogeneous and field catalysis follow. New definitions of catalyst and field catalysis are given. The class of material catalysts has been expanded and supplemented with field catalysts.
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Liu, Jingyue. « Advanced Electron Microscopy Characterization of Nanostructured Heterogeneous Catalysts ». Microscopy and Microanalysis 10, no 1 (22 janvier 2004) : 55–76. http://dx.doi.org/10.1017/s1431927604040310.

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Heterogeneous catalysis is one of the oldest nanosciences. Although model catalysts can be designed, synthesized, and, to a certain degree, characterized, industrial heterogeneous catalysts are often chemically and physically complex systems that have been developed through many years of catalytic art, technology, and science. The preparation of commercial catalysts is generally not well controlled and is often based on accumulated experiences. Catalyst characterization is thus critical to developing new catalysts with better activity, selectivity, and/or stability. Advanced electron microscopy, among many characterization techniques, can provide useful information for the fundamental understanding of heterogeneous catalysis and for guiding the development of industrial catalysts. In this article, we discuss the recent developments in applying advanced electron microscopy techniques to characterizing model and industrial heterogeneous catalysts. The importance of understanding the catalyst nanostructure and the challenges and opportunities of advanced electron microscopy in developing nanostructured catalysts are also discussed.
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Latos, Piotr, Anna Wolny et Anna Chrobok. « Supported Ionic Liquid Phase Catalysts Dedicated for Continuous Flow Synthesis ». Materials 16, no 5 (5 mars 2023) : 2106. http://dx.doi.org/10.3390/ma16052106.

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Heterogeneous catalysis, although known for over a century, is constantly improved and plays a key role in solving the present problems in chemical technology. Thanks to the development of modern materials engineering, solid supports for catalytic phases having a highly developed surface are available. Recently, continuous-flow synthesis started to be a key technology in the synthesis of high added value chemicals. These processes are more efficient, sustainable, safer and cheaper to operate. The most promising is the use of heterogeneous catalyst with column-type fixed-bed reactors. The advantages of the use of heterogeneous catalyst in continuous flow reactors are the physical separation of product and catalyst, as well as the reduction in inactivation and loss of the catalyst. However, the state-of-the-art use of heterogeneous catalysts in flow systems compared to homogenous ones remains still open. The lifetime of heterogeneous catalysts remains a significant hurdle to realise sustainable flow synthesis. The goal of this review article was to present a state of knowledge concerning the application of Supported Ionic Liquid Phase (SILP) catalysts dedicated for continuous flow synthesis.
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Du, Yuan-Peng, et Jeremy S. Luterbacher. « Designing Heterogeneous Catalysts for Renewable Catalysis Applications Using Metal Oxide Deposition ». CHIMIA International Journal for Chemistry 73, no 9 (18 septembre 2019) : 698–706. http://dx.doi.org/10.2533/chimia.2019.698.

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Heterogeneous catalysis has long been a workhorse for the chemical industry and will likely play a key role in the emerging area of renewable chemistry. However, renewable molecule streams pose unique challenges for heterogeneous catalysis due to their high oxygen content, frequent low volatility and the near constant presence of water. These constraints can often lead to the need for catalyst operation in harsh liquid phase conditions, which has compounded traditional catalyst deactivation issues. Oxygenated molecules are also frequently more reactive than petroleum-derived molecules, which creates a need for highly selective catalysts. Synthetic control over the nanostructured environment of catalytic active sites could facilitate the creation of both more stable and selective catalysts. In this review, we discuss the use of metal oxide deposition as an emerging strategy that can be used to synthesize and/or modify heterogeneous catalysts to introduce tailored nanostructures. Several important applications are reviewed, including the synthesis of high surface area mesoporous metal oxides, the enhancement of catalyst stability, and the improvement of catalyst selectivity.
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Holzwarth, Arnold, et Wilhelm F. Maier. « Catalytic Phenomena in Combinatorial Libraries of Heterogeneous Catalysts ». Platinum Metals Review 44, no 1 (1 janvier 2000) : 16–21. http://dx.doi.org/10.1595/003214000x4411621.

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Combinatorial catalysis is becoming a significant method for investigating the activities of large numbers of potential catalysts. A very important prerequisite for making use of combinatorial catalysis research is a reliable, fast and efficient technique for monitoring the catalytic activities. Emissivity-corrected infrared thermography, which monitors the heat changes resulting from the heat of reaction on catalyst surfaces, is such a technique. In this article we describe emissivity-corrected infrared thermography and demonstrate its performance, over time, in monitoring the catalytic activities of catalyst libraries. It is shown that not only can static relative activity be displayed, but also that catalyst-specific time-dependent properties, such as activation and deactivation phenomena can be demonstrated.
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Miceli, Mariachiara, Patrizia Frontera, Anastasia Macario et Angela Malara. « Recovery/Reuse of Heterogeneous Supported Spent Catalysts ». Catalysts 11, no 5 (1 mai 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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Jakab-Nácsa, Alexandra, Attila Garami, Béla Fiser, László Farkas et Béla Viskolcz. « Towards Machine Learning in Heterogeneous Catalysis—A Case Study of 2,4-Dinitrotoluene Hydrogenation ». International Journal of Molecular Sciences 24, no 14 (14 juillet 2023) : 11461. http://dx.doi.org/10.3390/ijms241411461.

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Utilization of multivariate data analysis in catalysis research has extraordinary importance. The aim of the MIRA21 (MIskolc RAnking 21) model is to characterize heterogeneous catalysts with bias-free quantifiable data from 15 different variables to standardize catalyst characterization and provide an easy tool to compare, rank, and classify catalysts. The present work introduces and mathematically validates the MIRA21 model by identifying fundamentals affecting catalyst comparison and provides support for catalyst design. Literature data of 2,4-dinitrotoluene hydrogenation catalysts for toluene diamine synthesis were analyzed by using the descriptor system of MIRA21. In this study, exploratory data analysis (EDA) has been used to understand the relationships between individual variables such as catalyst performance, reaction conditions, catalyst compositions, and sustainable parameters. The results will be applicable in catalyst design, and using machine learning tools will also be possible.
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Thèses sur le sujet "The heterogeneous catalyst"

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Guo, Chris. « Alkane Oxidation Catalysis by Homogeneous and Heterogeneous Catalyst ». Thesis, The University of Sydney, 2005. http://hdl.handle.net/2123/622.

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Abstract Cobalt-based complexes are widely used in industry and organic synthesis as catalysts for the oxidation of hydrocarbons. The Co/Mn/Br (known as "CAB system") catalyst system is effective for the oxidation of toluene. The Co/Mn/Br/Zr catalyst system is powerful for the oxidation of p-xylene, but not for the oxidation of toluene. [Co3O(OAc)5(OH)(py)3][PF6] (Co 3+ trimer 5) is more effective than [Co3O(OAc)6(py)3][PF6] (Co 3+ trimer 6) as a catalyst in the CAB catalyst system. Higher temperatures favour the oxidation of toluene. Zr 4+ does not enhance the oxidation of toluene. Zr 4+ could inhibit the oxidation of toluene in the combination of Co/Br/Zr, Co/Mn/Zr or Co/Zr. NHPI enhances the formation of benzyl alcohol, but the formation of other by-products is a problem for industrial processes. Complex(es) between cobalt, manganese and zirconium might be formed during the catalytic reaction. However, attempts at the preparation of complexes consisting of Co/Zr or Mn/Zr or Co3ZrP or Co8Zr4 clusters failed. The oxidation of cyclohexane to cyclohexanone and cyclohexanol is of great industrial significance. For the homogeneous catalysis at 50 o C and 3 bar N2 pressure, the activity order is: Mn(OAc)3 �2H2O > Mn12O12 cluster > Co 3+ trimer 6 > [Co3O(OAc)3(OH)2(py)5][PF6]2 (Co 3+ trimer 3) > Co 3+ trimer 5 > Co(OAc)2 �4H2O > [Co2(OAc)3(OH)2(py)4][PF6]-asym (Co dimerasym) > [Co2(OAc)3(OH)2(py)4][PF6]-sym (Co dimersym); whereas [Mn2CoO(OAc)6(py)3]�HOAc (Mn2Co complex) and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. But at 120 o C and 3 bar N2 pressure, the activity order is changed to: Co dimerasym > Co(OAc)2 �4H2O > Co trimer 3 and Mn(OAc)3 �2H2O > Co 3+ trimer 6 > Mn2Co complex > Co 3+ trimer 5 > Co dimersym > Mn12O12 cluster. The molar ratio of the products was close to cyclohexanol/cyclohexanone=2/1. Mn(II) acetate and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. Among those cobalt dimers and trimers, only the cobalt dimerasym survived after the stability tests, this means that [Co2(OAc)3(OH)2(py)4][PF6]-asym might be the active form for cobalt(II) acetate in the CAB system. Metal-substituted (silico)aluminophosphate-5 molecular sieves (MeAPO-5 and MeSAPO-5) are important heterogeneous catalysts for the oxidation of cyclohexane. The preparation of MeAPO-5 and MeSAPO-5 and their catalytic activities were studied. Pure MeAPO-5 and MeSAPO-5 are obtained and characterised. Four new pairs of bimetal-substituted MeAPO-5 and MeSAPO-5(CoZr, MnZr, CrZr and MnCo) were prepared successfully. Two novel trimetal-subtituted MeAPO-5 and MeSAPO-5 (MnCoZr) are reported here. Improved methods for the preparation of four monometal-substituted MeAPO-5 (Cr, Co, Mn and Zr) and for CoCe(S)APO-5 and CrCe(S)APO-5 are reported. Novel combinational mixing conditions for the formation of gel mixtures for Me(S)APO-5 syntheses have been developed. For the oxidation of cyclohexane by TBHP catalysed by MeAPO-5 and MeSAPO-5 materials, CrZrSAPO-5 is the only active MeSAPO-5 catalyst among those materials tested under conditions of refluxing in cyclohexane. Of the MeAPO-5 materials tested, whereas CrCeSAPO-5 has very little activity, CrZrAPO-5 and CrCeAPO-5 are very active catalysts under conditions of refluxing in cyclohexane. MnCoAPO-5, MnZrAPO-5 and CrAPO-5 are also active. When Cr is in the catalyst system, the product distribution is always cyclohexanone/cyclohexanol equals 2-3)/1, compared with 1/2 for other catalysts. For MeAPO-5, the activity at 150 o C and 10 bar N2 pressure is: CrZrAPO-5 > CrCeAPO-5 > CoZrAPO-5. For MeAPO-5 and MeSAPO-5, at 150 o C and 13 bar N2 pressure, the selectivity towards cyclohexanone is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5; and the selectivity towards cyclohexanol is: MnZrAPO-5 > CrZrAPO-5 > MnCoAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5. Overall the selectivity towards the oxidation of cyclohexane is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5. The amount of water in the system can affect the performance of CrCeAPO-5, but has almost no effect on CrZrAPO-5. Metal leaching is another concern in potential industrial applications of MeAPO-5 and MeSAPO-5 catalysts. The heterogeneous catalysts prepared in the present work showed very little metal leaching. This feature, coupled with the good selectivities and effectivities, makes them potentially very useful.
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Guo, Chris. « Alkane Oxidation Catalysis by Homogeneous and Heterogeneous Catalyst ». University of Sydney. Chemistry, 2005. http://hdl.handle.net/2123/622.

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Abstract Cobalt-based complexes are widely used in industry and organic synthesis as catalysts for the oxidation of hydrocarbons. The Co/Mn/Br (known as "CAB system") catalyst system is effective for the oxidation of toluene. The Co/Mn/Br/Zr catalyst system is powerful for the oxidation of p-xylene, but not for the oxidation of toluene. [Co3O(OAc)5(OH)(py)3][PF6] (Co 3+ trimer 5) is more effective than [Co3O(OAc)6(py)3][PF6] (Co 3+ trimer 6) as a catalyst in the CAB catalyst system. Higher temperatures favour the oxidation of toluene. Zr 4+ does not enhance the oxidation of toluene. Zr 4+ could inhibit the oxidation of toluene in the combination of Co/Br/Zr, Co/Mn/Zr or Co/Zr. NHPI enhances the formation of benzyl alcohol, but the formation of other by-products is a problem for industrial processes. Complex(es) between cobalt, manganese and zirconium might be formed during the catalytic reaction. However, attempts at the preparation of complexes consisting of Co/Zr or Mn/Zr or Co3ZrP or Co8Zr4 clusters failed. The oxidation of cyclohexane to cyclohexanone and cyclohexanol is of great industrial significance. For the homogeneous catalysis at 50 o C and 3 bar N2 pressure, the activity order is: Mn(OAc)3 �2H2O > Mn12O12 cluster > Co 3+ trimer 6 > [Co3O(OAc)3(OH)2(py)5][PF6]2 (Co 3+ trimer 3) > Co 3+ trimer 5 > Co(OAc)2 �4H2O > [Co2(OAc)3(OH)2(py)4][PF6]-asym (Co dimerasym) > [Co2(OAc)3(OH)2(py)4][PF6]-sym (Co dimersym); whereas [Mn2CoO(OAc)6(py)3]�HOAc (Mn2Co complex) and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. But at 120 o C and 3 bar N2 pressure, the activity order is changed to: Co dimerasym > Co(OAc)2 �4H2O > Co trimer 3 and Mn(OAc)3 �2H2O > Co 3+ trimer 6 > Mn2Co complex > Co 3+ trimer 5 > Co dimersym > Mn12O12 cluster. The molar ratio of the products was close to cyclohexanol/cyclohexanone=2/1. Mn(II) acetate and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. Among those cobalt dimers and trimers, only the cobalt dimerasym survived after the stability tests, this means that [Co2(OAc)3(OH)2(py)4][PF6]-asym might be the active form for cobalt(II) acetate in the CAB system. Metal-substituted (silico)aluminophosphate-5 molecular sieves (MeAPO-5 and MeSAPO-5) are important heterogeneous catalysts for the oxidation of cyclohexane. The preparation of MeAPO-5 and MeSAPO-5 and their catalytic activities were studied. Pure MeAPO-5 and MeSAPO-5 are obtained and characterised. Four new pairs of bimetal-substituted MeAPO-5 and MeSAPO-5(CoZr, MnZr, CrZr and MnCo) were prepared successfully. Two novel trimetal-subtituted MeAPO-5 and MeSAPO-5 (MnCoZr) are reported here. Improved methods for the preparation of four monometal-substituted MeAPO-5 (Cr, Co, Mn and Zr) and for CoCe(S)APO-5 and CrCe(S)APO-5 are reported. Novel combinational mixing conditions for the formation of gel mixtures for Me(S)APO-5 syntheses have been developed. For the oxidation of cyclohexane by TBHP catalysed by MeAPO-5 and MeSAPO-5 materials, CrZrSAPO-5 is the only active MeSAPO-5 catalyst among those materials tested under conditions of refluxing in cyclohexane. Of the MeAPO-5 materials tested, whereas CrCeSAPO-5 has very little activity, CrZrAPO-5 and CrCeAPO-5 are very active catalysts under conditions of refluxing in cyclohexane. MnCoAPO-5, MnZrAPO-5 and CrAPO-5 are also active. When Cr is in the catalyst system, the product distribution is always cyclohexanone/cyclohexanol equals 2-3)/1, compared with 1/2 for other catalysts. For MeAPO-5, the activity at 150 o C and 10 bar N2 pressure is: CrZrAPO-5 > CrCeAPO-5 > CoZrAPO-5. For MeAPO-5 and MeSAPO-5, at 150 o C and 13 bar N2 pressure, the selectivity towards cyclohexanone is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5; and the selectivity towards cyclohexanol is: MnZrAPO-5 > CrZrAPO-5 > MnCoAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5. Overall the selectivity towards the oxidation of cyclohexane is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5. The amount of water in the system can affect the performance of CrCeAPO-5, but has almost no effect on CrZrAPO-5. Metal leaching is another concern in potential industrial applications of MeAPO-5 and MeSAPO-5 catalysts. The heterogeneous catalysts prepared in the present work showed very little metal leaching. This feature, coupled with the good selectivities and effectivities, makes them potentially very useful.
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El, Solh Tarek. « Heterogeneous catalyst for methane reforming ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0007/MQ30748.pdf.

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Khurshid, Samir Najem Aldeen. « Biodiesel production by using heterogeneous catalyst ». Thesis, KTH, Skolan för kemivetenskap (CHE), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145953.

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Weller, Suzanne Catherine. « Electron microscopy of heterogeneous catalyst particles ». Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396431.

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Elhage, Ayda. « Palladium-based Catalyst for Heterogeneous Photocatalysis ». Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39388.

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Over the past decade, heterogeneous photocatalysis have gained lots of interest and attention among the organic chemistry community due to its applicability as an alternative to its homogeneous counterpart. Heterogeneous catalysis offers the advantages of easy separation and reusability of the catalyst. Several studies showed that under optimized conditions, efficient and highly selective catalytic systems could be developed using supported metal/metal oxide nanoparticles. In this dissertation, we summarize the progress in the development of supported palladium nanoparticles for different types of organic reactions. Palladium-decorated TiO2 is a moisture, air-tolerant, and versatile catalyst. The direct excitation of Pd nanoparticles selectively isomerized the benzyl-substituted alkenes to phenyl-substituted alkenes (E-isomer) with complete conversion over Pd@TiO2 under H2-free conditions. Likewise, light excited Pd nanoparticles catalyzed Sonogashira coupling, a C-C coupling reaction between different aryl iodides and acetylenes under very mild conditions in short reaction times. On the other hand, UV irradiation of Pd@TiO2 in alcoholic solutions promotes alkenes hydrogenation at room temperature under Argon. Thus, The photocatalytic activity of Pd@TiO2 can be easily tuned by changing the irradiation wavelength. Nevertheless, some of these systems suffer from catalyst deactivation, one of the main challenges faced in heterogeneous catalysis that decreases the reusability potential of the materials. In order to overcome this problem, we developed an innovative method called “Catalytic Farming”. Our reactivation strategy is based on the crop rotation system used in agriculture. Thus, alternating different catalytic reactions using the same catalyst can reactivate the catalyst surface by restoring its oxidation states and extend the catalyst lifetime along with its selectivity and efficiency. In this work, the rotation strategy is illustrated by Sonogashira coupling –problem reaction that depletes the catalyst– and Ullmann homocoupling –plausible recovery reaction that restores the oxidation state of the catalyst (Pd@TiO2). The selection of the reactions in this approach is based on mechanistic studies that include the role of the solvent and evaluation of the palladium oxidation state after each reaction. In a more exploratory analysis, we successfully demonstrated that Pd nanoparticles could be supported in a wide range of materials, including inert ones such as nanodiamonds or glass fibers. The study of the action spectrum shows that direct excitation of the Pd nanoparticles is a requisite for Sonogashira coupling reactions. The main advantages of heterogeneous catalysis compared to its homogeneous counterpart are easy separation and reusability of the catalyst. Finally in order to facilitate catalyst separation from batch reaction and develop a suitable catalytic system for continuous flow chemistry, we employed glass fibers as catalyst support for a wide variety of thermal and photochemical organic reactions including C-C coupling, dehalogenation and cycloaddition. Different metal/metal oxide nanoparticles, namely Pd, Co, Cu, Au, and Ru were deposited on glass wool and fully characterized. As a proof of concept, Pd decorated glass fibers were employed in heterogeneous flow photocatalysis for Sonogashira coupling and reductive de-halogenation of aryl iodides.
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Ishtchenko, Vera. « Novel heterogeneous oxidation catalyst for organic compounds ». Thesis, De Montfort University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422594.

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Ahmad, Mushtaq. « Characterization of promoted supported platinum catalyst ». Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/13273.

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9

Meyer, Simon [Verfasser]. « Carbide Materials as Catalysts and Catalyst Supports for Applications in Water Electrolysis and in Heterogeneous Catalysis / Simon Meyer ». München : Verlag Dr. Hut, 2014. http://d-nb.info/1058284967/34.

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Tangale, N. P. « Zeolite based micro-mesoporous composites : synthesis, characterization and catalytic performance as heterogeneous catalyst for valorization of sugar ». Thesis(Ph.D.), CSIR- National Chemical Laboratory, Pune, 2018. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/4576.

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Livres sur le sujet "The heterogeneous catalyst"

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Supported metals in catalysis. 2e éd. London : Imperial College Press : Distributed by World Scientific, 2012.

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2

Weller, Suzanne Catherine. Electron microscopy of heterogeneous catalyst particles. Birmingham : University of Birmingham, 2002.

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Ziolek, Maria. Niobium species in heterogeneous catalysts used for oxiditation [i.e. : oxidation] processes-selected aspects. New York : Nova Science Publishers, 2011.

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Enantioselective titanium-catalysed transformations. New Jersey : Imperial College Press, 2015.

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Itsuno, Shinichi. Polymeric chiral catalyst design and chiral polymer synthesis. Hoboken, N.J : Wiley, 2011.

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Ma, Zhen, et Sheng Dai, dir. Heterogeneous Gold Catalysts and Catalysis. Cambridge : Royal Society of Chemistry, 2014. http://dx.doi.org/10.1039/9781782621645.

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J, Thomas W., dir. Principles and practice of heterogeneous catalysis. Weinheim : VCH, 1996.

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Heterogeneous reactor design. Boston : Butterworth, 1985.

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Heterogeneous catalysis : Fundamentals and applications. Amsterdam : Elsevier, 2012.

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Synthesis of solid catalysts. Weinheim : Wiley-VCH, 2009.

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Chapitres de livres sur le sujet "The heterogeneous catalyst"

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Hutchings, Graham J., et Jacques C. Védrine. « Heterogeneous Catalyst Preparation ». Dans Basic Principles in Applied Catalysis, 215–58. Berlin, Heidelberg : Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-05981-4_6.

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Sachdeva, Garima, Dipti Vaya, Varun Rawat et Pooja Rawat. « Solid-supported Catalyst in Heterogeneous Catalysis ». Dans Heterogeneous Catalysis in Organic Transformations, 105–25. Boca Raton : CRC Press, 2022. http://dx.doi.org/10.1201/9781003126270-5.

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Schmal, Martin. « Catalyst Preparation ». Dans Heterogeneous Catalysis and its Industrial Applications, 161–87. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-09250-8_7.

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Taarit, Y. Ben, et J. Fraissard. « Nuclear Magnetic Resonance in Heterogeneous Catalysis ». Dans Catalyst Characterization, 91–129. Boston, MA : Springer US, 1994. http://dx.doi.org/10.1007/978-1-4757-9589-9_5.

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De Vos, Dirk E., Mario De Bruyn, Vasile I. Parvulescu, Florian G. Cocu et Pierre A. Jacobs. « Heterogeneous Diastereoselective Catalysis ». Dans Chiral Catalyst Immobilization and Recycling, 283–306. Weinheim, Germany : Wiley-VCH Verlag GmbH, 2007. http://dx.doi.org/10.1002/9783527613144.ch12.

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Herrmann, J. M. « Applications of Electrical Conductivity Measurements in Heterogeneous Catalysis ». Dans Catalyst Characterization, 559–84. Boston, MA : Springer US, 1994. http://dx.doi.org/10.1007/978-1-4757-9589-9_20.

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Jones, William, John M. Thomas, D. Tilak B. Tennakoon, Robert Schlogl et Paul Diddams. « The Role of Intercalates in Heterogeneous Catalysis ». Dans Catalyst Characterization Science, 472–84. Washington, DC : American Chemical Society, 1985. http://dx.doi.org/10.1021/bk-1985-0288.ch040.

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Bi, Songhu, Zhen Geng, Liming Jin, Mingzhe Xue et Cunman Zhang. « Porous Heterogeneous Sulfide Nickel/Nickel Iron Alloy Catalysts for Oxygen Evolution Reaction of Alkaline Water Electrolysis at High Current Density ». Dans Proceedings of the 10th Hydrogen Technology Convention, Volume 1, 116–21. Singapore : Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-8631-6_13.

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AbstractAlkaline water electrolysis is the important pathway for the green hydrogen production, where oxygen evolution reaction (OER) is the rate-limiting step due to the sluggish reaction kinetics. Transition metal heterogeneous catalyst is the kind of important OER catalyst for alkaline water electrolysis due to its good performance, low price and environmental friendliness. In this work, the porous sulfide nickel@nickel iron alloy catalyst (i.e. NM/NS@Ni3Fe) is prepared by the designed high-temperature vulcanization and multi-step electrodeposition method. The NM/NS@Ni3Fe catalyst exhibits an outstanding OER performance in an alkaline environment, with a low potential of 1.53 V at high current density of 1000 mA cm−2 and a low Tafel slope of 89 mV dec−1. The excellent OER performance is attributed to the unique electronic structure of Ni3S2/Ni3Fe heterogeneous interface and the catalyst layer with porous structure. The results indicate that Ni3S2 provides good electronic conductivity and the low electronegativity S atoms increase the formation of oxygen vacancies, which effectively improves the OER performance. In addition, the hydrophilic and porous structure of the electrode facilitates bubbles release and electrolyte flow at high current density. It provides the guidance for the design of porous heterogeneous OER catalysts with good-performance.
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Werpy, Todd A., Laurent J. Michot et Thomas J. Pinnavaia. « New Tubular Silicate-Layered Silicate Nanocomposite Catalyst ». Dans Novel Materials in Heterogeneous Catalysis, 119–28. Washington, DC : American Chemical Society, 1990. http://dx.doi.org/10.1021/bk-1990-0437.ch012.

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Gevert, S. Börje, Peter Abrahamsson et Sven G. Järås. « Oligomerization of Isobutene with an Improved Catalyst ». Dans Novel Materials in Heterogeneous Catalysis, 272–78. Washington, DC : American Chemical Society, 1990. http://dx.doi.org/10.1021/bk-1990-0437.ch025.

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Actes de conférences sur le sujet "The heterogeneous catalyst"

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Wüthrich, Kurt, R. H. Grubbs, T. Visart de Bocarmé et Anne De Wit. « Heterogeneous Catalysis and Characterization of Catalyst Surfaces ». Dans 24th International Solvay Conference on Chemistry. WORLD SCIENTIFIC, 2018. http://dx.doi.org/10.1142/9789813237179_others02.

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Willetts, D. V., et M. R. Harris. « Homogeneous Catalysis for CO2 Lasers ». Dans Coherent Laser Radar. Washington, D.C. : Optica Publishing Group, 1991. http://dx.doi.org/10.1364/clr.1991.mc2.

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The attainment of long sealed gas lifetimes is one of the few outstanding areas of carbon dioxide laser technology which need to be addressed. Electron impact dissociation of carbon dioxide can be overcome by use of a catalyst to recombine the carbon monoxide and oxygen so formed. Heterogeneous catalysts have been extensively studied; although effective, such catalysts necessarily introduce problems of dust release in a vibrating environment and impedance to gas flow. In addition, attention must be paid to isotopic exchange between catalyst and gas. These difficulties disappear if a suitable homogenous catalyst can be found.
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Samad, Wan Zurina, Wan Nor Roslam Wan Isahak, Kin Hong Liew, Norazzizi Nordin, Mohd Ambar Yarmo et Muhammad Rahimi Yusop. « Ru/FTO : Heterogeneous catalyst for glycerol hydrogenolysis ». Dans THE 2014 UKM FST POSTGRADUATE COLLOQUIUM : Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2014 Postgraduate Colloquium. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4895207.

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Hlavatý, T., M. Isoz et M. Khýr. « Simulation of Heterogeneously-Catalyzed Non-Isothermal Reactive Flow in Industrial Packed Beds ». Dans Topical Problems of Fluid Mechanics 2023. Institute of Thermomechanics of the Czech Academy of Sciences ; CTU in Prague Faculty of Mech. Engineering Dept. Tech. Mathematics, 2023. http://dx.doi.org/10.14311/tpfm.2023.007.

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Packed bed reactors are the most frequently used devices to perform heterogeneously catalyzed reactions on industrial scales. An industrial real-life heterogeneous catalysis is complex process that combines fully three-dimensional mass, momentum and energy transport on several scales. In the present work, we leverage our previously developed CFD solver for non-isothermal heterogeneously catalyzed reactive flow based on the finite volume method and couple it with our in-house DEM-based method for preparation of random packed beds. The resulting framework is verified in the simplified cases against available analytical solutions and correlations and is used to study an industrially-relevant case of ethylene oxychlorination performed in a tubular packed bed comprising CuCl₂-coated catalyst carrying particles. In particular, we compare properties of three different industrially used catalyst carrying particles: Raschig rings, Reformax, and Wagon wheels.
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Kudo, Akihiko. « Heterogeneous Photocatalysts for water splitting and CO2 reduction ». Dans Catalyst Design Strategies for Photo- and Electrochemical Fuel Synthesis. València : FUNDACIO DE LA COMUNITAT VALENCIANA SCITO, 2023. http://dx.doi.org/10.29363/nanoge.ecat.2023.020.

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Raoufi, Arman, Sagar Kapadia et James C. Newman. « Sensitivity Analysis and Computational Optimization of Fuel Reformer ». Dans ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2016 Power Conference and the ASME 2016 10th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fuelcell2016-59110.

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In this study, the catalytic combustion of methane is numerically investigated using an unstructured, implicit, fully coupled finite volume approach. Nonlinear system of equations is solved by Newton’s method. The catalytic partial oxidation of methane over both platinum and rhodium catalysts are studied three-dimensionally. Eight gas-phase species (CH4, CO2, H2O, N2, O2, CO, OH and H2) are considered for the simulation. Surface chemistry is modeled by detailed reaction mechanisms including 24 heterogeneous reactions with 11 surface-adsorbed species for Pt catalyst and 38 heterogeneous reactions with 20 surface-adsorbed species for Rh catalyst. The numerical results are compared with the experimental data and good agreement is observed. The performance of the fuel reformer is analyzed for two different catalysts. The sensitivity analysis for the reactor is performed using three different approaches: finite difference, direct differentiation and adjoint method. The design cycle is performed using two gradient-based optimization algorithms to improve the value of the implemented cost function and optimize the reactor performance.
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Sudiyarmanto, Luthfiana Nurul Hidayati, Anis Kristiani et Fauzan Aulia. « Hydrogenation of citral into its derivatives using heterogeneous catalyst ». Dans PROCEEDINGS OF THE 3RD INTERNATIONAL SYMPOSIUM ON APPLIED CHEMISTRY 2017. Author(s), 2017. http://dx.doi.org/10.1063/1.5011901.

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Yang, Kang, et Chen-Guang Liu. « HETEROGENEOUS CATALYST IN IONIC LIQUIDS : ZIRCONIA SUPPORTED GOLD NANOPARTICLES ». Dans 2015 International Conference on Material Engineering and Mechanical Engineering (MEME2015). WORLD SCIENTIFIC, 2016. http://dx.doi.org/10.1142/9789814759687_0149.

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Oprescu, Elena-Emilia. « CONVERSION OF BIOMASS UNDER HETEROGENEOUS CATALYST INTO LEVULINIC ESTERS ». Dans 19th SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings. STEF92 Technology, 2019. http://dx.doi.org/10.5593/sgem2019/4.1/s17.014.

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Rożeń, Antoni. « A Simple One-Dimensional Model of a Passive Hydrogen Recombiner ». Dans 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-31124.

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A simple one-dimensional model allowing fast predictions of: a gas composition and temperature profiles, a catalyst temperature profile and an overall hydrogen recombination degree has been developed for a passive catalytic recombiner. The model assumes that heat and mass transport processes, taking place in vertical channels between catalyst plates, occur in a highly non-isothermal, developing laminar gas flow and in conditions of mixed convection. A kinetic model of heterogeneous catalysis was implemented into the model and the heat radiation from the catalyst surface was accounted for. The model with no adjustable parameters was verified against experimental results available in literature and results of numerical simulations obtained by CFD methods.
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Rapports d'organisations sur le sujet "The heterogeneous catalyst"

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Contreras, Anthony Marshall. Nanolithographic Fabrication and Heterogeneous Reaction Studies ofTwo-Dimensional Platinum Model Catalyst Systems. Office of Scientific and Technical Information (OSTI), mai 2006. http://dx.doi.org/10.2172/886081.

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Kalel, Rahul. Silica Immobilized Brønsted-Lewis Acidic Ionic Liquid : Heterogeneous catalyst for Condensation-Aromatization in the Synthesis of 2-(4-nitrophenyl)-1H-benzimidazole by cooperative catalysis. Peeref, mars 2023. http://dx.doi.org/10.54985/peeref.2303p6889123.

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Augustine, R. L. Systematic preparation of selective heterogeneous catalysts. Office of Scientific and Technical Information (OSTI), novembre 1991. http://dx.doi.org/10.2172/6905689.

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Boszormenyi, Istvan. Model heterogeneous acid catalysts and metal-support interactions : A combined surface science and catalysis study. Office of Scientific and Technical Information (OSTI), mai 1991. http://dx.doi.org/10.2172/10115869.

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Boszormenyi, I. Model heterogeneous acid catalysts and metal-support interactions : A combined surface science and catalysis study. Office of Scientific and Technical Information (OSTI), mai 1991. http://dx.doi.org/10.2172/6827194.

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Surko, Clifford M. Spatiotemporal Dynamics in Heterogeneous Catalysis. Fort Belvoir, VA : Defense Technical Information Center, juillet 2001. http://dx.doi.org/10.21236/ada389981.

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Wilfred T. Tysoe. Molecular-level Design of Heterogeneous Chiral Catalysts. Office of Scientific and Technical Information (OSTI), avril 2007. http://dx.doi.org/10.2172/902534.

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Tysoe, Wilfred, Andrew Gellman, Francisco Zaera et Charles Sykes. Molecular-Level Design of Heterogeneous Chiral Catalysts. Office of Scientific and Technical Information (OSTI), mai 2019. http://dx.doi.org/10.2172/1510980.

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Gellman, Andrew John, David S. Sholl, Wilfred T. Tysoe et Francisco Zaera. Molecular-level Design of Heterogeneous Chiral Catalysts. Office of Scientific and Technical Information (OSTI), avril 2013. http://dx.doi.org/10.2172/1160339.

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Ye, Rong. Development of Molecular Catalysts to Bridge the Gap between Heterogeneous and Homogeneous Catalysts. Office of Scientific and Technical Information (OSTI), septembre 2017. http://dx.doi.org/10.2172/1488417.

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