scholarly journals Mesoporous Palladium N,N’-Bis(3-Allylsalicylidene)o-Phenylenediamine-Methyl Acrylate Resins as Heterogeneous Catalysts for the Heck Coupling Reaction

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2612
Author(s):  
Claudio Mella ◽  
Cecilia C. Torres ◽  
Gina Pecchi ◽  
Cristian H. Campos
Keyword(s):  
Methyl Acrylate ◽  
Heterogeneous Catalysts ◽  
Suspension Polymerization ◽  
Metal Chelate ◽  
Reaction Medium ◽  
Coupling Reaction ◽  
Analytical Techniques ◽  
Catalytic Performance ◽  
Catalyst Stability ◽  
Heck Coupling

Palladium N,N’-bis(3-allylsalicylidene)o-phenylenediamine complex (PdAS) immobilized onto mesoporous polymeric methyl acrylate (MA) based resins (PdAS(x)-MA, x = 1, 2, 5, or 10 wt.%) were successfully prepared as heterogeneous catalysts for the Heck reaction. The catalysts were synthesized via radical suspension polymerization using PdAS as a metal chelate monomer, divinylbenzene and MA as co-monomers. The effect of the PdAS(x) content on the physicochemical properties of the resins is also reported. The catalysts were characterized by using a range of analytical techniques. The large surface area (>580 m2·g−1) and thermal stability (up to 250 °C) of the PdAS(x)-MA materials allows their application as catalysts in the C–C coupling reaction between iodobenzene and MA in the presence of trimethylamine at 120 °C using DMF as the solvent. The PdAS(10)-MA catalyst exhibited the highest catalytic performance with no significant catalytic loss being observed after five reuses, thereby indicating excellent catalyst stability in the reaction medium.

scholarly journals Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

2020 ◽  
Vol 16 ◽  
pp. 2477-2483 ◽  
Author(s):  
Tony Jin ◽  
Malickah Hicks ◽  
Davis Kurdyla ◽  
Sabahudin Hrapovic ◽  
Edmond Lam ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Coupling Reaction ◽  
Product Yield ◽  
Pd Nanoparticles ◽  
Coupling Model ◽  
Coupling Reactions ◽  
Heck Coupling ◽  
One Pot ◽  
Cross Coupling Reactions ◽  
Chitin And Chitosan

In this report, chitin and chitosan nanocrystals were used as biomass-based supports for Pd nanoparticles (NPs) used as a heterogeneous catalyst for the Heck coupling reaction. By using a one-pot fabrication method, a Pd salt precursor was directly reduced and deposited onto these nanocrystal catalysts. Characterization of these nanocomposites showed disperse Pd NPs on the surfaces of the chitinous nanocrystals. Heck coupling model reactions revealed full product yield in relatively benign conditions, outcompeting the use of other catalysts supported on biomass-based nanomaterials, including cellulose nanocrystals. These initial results show the potential for using chitinous nanomaterials as effective catalyst supports in cross-coupling reactions.

Effect of Ultrasound on the Properties of Heterogeneous Catalysts for Sono-Fenton Oxidation Processes

2008 ◽  
Vol 11 (1) ◽  
Author(s):  
Juan A. Melero ◽  
Fernando Martínez ◽  
Raúl Molina
Keyword(s):  
Particle Size ◽  
Iron Oxides ◽  
Heterogeneous Catalysts ◽  
Reaction Medium ◽  
Catalyst Particle ◽  
Ultrasound Irradiation ◽  
Catalytic Performance ◽  
Nanocomposite Material ◽  
High Dispersion ◽  
Concentration Changes

AbstractThe objective of this research is to assess the effect of ultrasonic irradiation (20 KHz) on the catalytic activity and catalyst particle size of different iron-containing solids (hematite/SBA-15 nanocomposite; hematite; goethite). The catalytic activities of the different catalysts were investigated in the sono-Fenton degradation of a phenolic aqueous solution in the presence of hydrogen peroxide at pH 3. The catalytic performance was monitored in terms of phenol and total organic carbon (TOC) conversions. The concentration changes of different by-products coming from incomplete mineralization of phenol were also monitored. The stability was examined by measuring iron dissolved in the reaction medium after reaction. The degradation rate in the presence of the nanocomposite material was higher than that when SBA-15 and hematite were separately suspended and also higher than that found for the bulk and unsupported iron oxides (hematite and goethite). The particle size of the catalysts suffers serious changes during the sonication which strongly depend on their nature. Unlike nanocomposite material which presents a deep catalyst particle reduction, unsupported bulk iron oxides yield an agglomeration of the particles. The considerable enhancement of the activity achieved with the nanocomposite material is due to the catalyst particles size reduction during ultrasound irradiation as well as the high dispersion of the metallic species over the mesostructured support.

Magnetically recyclable Pd/γ-AlOOH@Fe3O4 catalysts and their catalytic performance for the Heck coupling reaction

2014 ◽  
Vol 57 (6) ◽  
pp. 866-872 ◽  
Author(s):  
Hao Yang ◽  
ShengFu Ji ◽  
XueFei Liu ◽  
DanNi Zhang ◽  
Da Shi
Keyword(s):  
Coupling Reaction ◽  
Catalytic Performance ◽  
Heck Coupling

Catalytic performance study of nano-cobalt: a catalyst for complement to the Heck coupling reaction

2017 ◽  
Vol 24 (4) ◽  
pp. 1095-1103 ◽  
Author(s):  
K. S. Jithendra Kumara ◽  
G. Krishnamurthy ◽  
B. E. Kumara Swamy ◽  
N. Sunil Kumar ◽  
Mohan Kumar
Keyword(s):  
Coupling Reaction ◽  
Catalytic Performance ◽  
Heck Coupling ◽  
Performance Study

scholarly journals Piperidinium and Pyrrolidinium Ionic Liquids as Precursors in the Synthesis of New Platinum Catalysts for Hydrosilylation

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 919 ◽  
Author(s):  
Magdalena Jankowska-Wajda ◽  
Olga Bartlewicz ◽  
Przemysław Pietras ◽  
Hieronim Maciejewski
Keyword(s):  
Ionic Liquids ◽  
Heterogeneous Catalysts ◽  
Glycidyl Ether ◽  
Reaction Medium ◽  
Platinum Complexes ◽  
Catalytic Performance ◽  
Attractive Alternative ◽  
High Catalytic Activity ◽  
Allyl Glycidyl Ether ◽  
Catalytic Cycles

Six new air-stable anionic platinum complexes were synthesized in simple reactions of piperidinium [BMPip]Cl or pyrrolidinium [BMPyrr]Cl ionic liquids with platinum compounds ([Pt(cod)Cl2] or K2[PtCl6]). All these compounds were subjected to isolation and spectrometric characterization using NMR and ESI-MS techniques. Furthermore, the determination of melting points and thermal stability of the above derivatives was performed with the use of thermogravimetric analysis. The catalytic performance of the synthesized complexes was tested in hydrosilylation of 1-octene and allyl glycidyl ether with 1,1,1,3,5,5,5-heptamethyltrisiloxane. The study has shown that they have high catalytic activity and are insoluble in the reaction medium which enabled them to isolate and reuse them in consecutive catalytic cycles. The most active complex [BMPip]2[PtCl6] makes it possible to conduct at least 10 catalytic runs without losing activity which makes it an attractive alternative not only to commonly used homogeneous catalysts, but also to heterogeneous catalysts for hydrosilylation processes. The activity of the studied catalysts is also affected by the kind of anion and, to some extent, the kind of cation.

Catalysts for hydrogenation of CO2 into components of motor fuels

2020 ◽  
pp. 1-18
Author(s):  
Yu.V. Bilokopytov ◽  
◽  
S.L. Melnykova ◽  
N.Yu. Khimach ◽  
◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Heterogeneous Catalysts ◽  
Fossil Fuels ◽  
Catalyst Stability ◽  
Co2 Conversion ◽  
Active Components ◽  
Synthesis Conditions ◽  
Hydrogenation Of Co2 ◽  
Mesoporous Zeolites ◽  
Motor Fuels

CO2 is a harmful greenhouse gas, a product of chemical emissions, the combustion of fossil fuels and car exhausts, and it is a widely available source of carbon. The review considers various ways of hydrogenation of carbon dioxide into components of motor fuels - methanol, dimethyl ether, ethanol, hydrocarbons - in the presence of heterogeneous catalysts. At each route of conversion of CO2 (into oxygenates or hydrocarbons) the first stage is the formation of CO by the reverse water gas shift (rWGS) reaction, which must be taken into account when catalysts of process are choosing. The influence of chemical nature, specific surface area, particle size and interaction between catalyst components, as well as the method of its production on the CO2 conversion processes is analyzed. It is noted that the main active components of CO2 conversion into methanol are copper atoms and ions which interact with the oxide components of the catalyst. There is a positive effect of other metals oxides additives with strong basic centers on the surface on the activity of the traditional copper-zinc-aluminum oxide catalyst for the synthesis of methanol from the synthesis gas. The most active catalysts for the synthesis of DME from CO2 and H2 are bifunctional. These catalysts contain both a methanol synthesis catalyst and a dehydrating component, such as mesoporous zeolites with acid centers of weak and medium strength, evenly distributed on the surface. The synthesis of gasoline hydrocarbons (≥ C5) is carried out through the formation of CO or CH3OH and DME as intermediates on multifunctional catalysts, which also contain zeolites. Hydrogenation of CO2 into ethanol can be considered as an alternative to the synthesis of ethanol through the hydration of ethylene. High activation energy of carbon dioxide, harsh synthesis conditions as well as high selectivity for hydrocarbons, in particular methane remains the main problems. Further increase of selectivity and efficiency of carbon dioxide hydrogenation processes involves the use of nanocatalysts taking into account the mechanism of CO2 conversion reactions, development of methods for removing excess water as a by-product from the reaction zone and increasing catalyst stability over time.

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