Packing polymorphism in 3-amino-2-pyrazinecarboxylate based tin(ii) complexes and their catalytic activity towards cyanosilylation of aldehydes

3-Amino-2-pyrazinecarboxylic acid is used to synthesize two new mononuclear interconvertible packing polymorphs of tin(ii) which act as heterogeneous catalysts for the cyanosilylation of aldehydes with trimethylsilyl cyanide.

Download Full-text

Lewis Acid-Promoted Suzuki Reaction using Palladium Chloride Anchored on a Polymer as a Catalyst

Australian Journal of Chemistry ◽

10.1071/ch08066 ◽

2008 ◽

Vol 61 (8) ◽

pp. 610 ◽

Cited By ~ 12

Author(s):

Guozhi Fan ◽

Hanjun Zhang ◽

Siqing Cheng ◽

Zhandong Ren ◽

Zhijun Hu ◽

...

Keyword(s):

Catalytic Activity ◽

Lewis Acid ◽

Lewis Acids ◽

Heterogeneous Catalysts ◽

Suzuki Reaction ◽

Cross Coupling ◽

Palladium Chloride ◽

Coupling Reactions ◽

Cross Coupling Reactions ◽

Recoverable Catalyst

Palladium chloride anchored on polystyrene modified by 5-amino-1,10-phenanthroline was prepared and used as an efficient recoverable catalyst for Suzuki cross-coupling reactions. The heterogeneous catalysts can be easily separated from the reaction mixture and reused for five cycles without significant Pd leaching and loss of catalytic activity. Rate enhancement in the Suzuki reaction by Lewis acids was also studied.

Download Full-text

A facile approach to fabricate halloysite/metal nanocomposites with preformed and in situ synthesized metal nanoparticles: a comparative study of their enhanced catalytic activity

Dalton Transactions ◽

10.1039/c5dt00830a ◽

2015 ◽

Vol 44 (19) ◽

pp. 8906-8916 ◽

Cited By ~ 29

Author(s):

Sankar Das ◽

Subhra Jana

Keyword(s):

Catalytic Activity ◽

Comparative Study ◽

Metal Nanoparticles ◽

Heterogeneous Catalysts ◽

Cost Effective ◽

Environmentally Benign ◽

Metal Nanocomposites

Halloysite/metal nanocomposites have been synthesized through the immobilization of preformed and in situ synthesized metal nanoparticles over halloysite surfaces, which in turn produce efficient, cost-effective, and environmentally benign heterogeneous catalysts.

Download Full-text

Towards highly active heterogeneous catalysts via a sequential noncovalent bonding strategy

New Journal of Chemistry ◽

10.1039/d1nj04303j ◽

2021 ◽

Author(s):

Ruixue Wang ◽

Ying Yue ◽

Huiying Wei ◽

Jinxin Guo ◽

Yanzhao Yang

Keyword(s):

Catalytic Activity ◽

Heterogeneous Catalysts ◽

High Catalytic Activity ◽

Synthetic Route ◽

Surface Ligands ◽

Highly Active ◽

Noncovalent Bonding ◽

Excellent Stability

Here, a novel synthetic route of ceria-based nanocatalysts with high catalytic activity and excellent stability was constructed by utilizing function groups from surface ligands. The surface of ceria nanorods were...

Download Full-text

Heterogeneization of alpha diimines nickel catalysts for the polymerization of ethylene and methylmethacrylate

e-Polymers ◽

10.1515/epoly.2010.10.1.1643 ◽

2010 ◽

Vol 10 (1) ◽

Author(s):

Inês Matos ◽

Auguste Fernandes ◽

Rita Catalão ◽

Ana M. Botelho do Rego ◽

José R. Ascenso ◽

...

Keyword(s):

Catalytic Activity ◽

Metal Cation ◽

Organometallic Compound ◽

Heterogeneous Catalysts ◽

Active Catalyst ◽

Organic Ligand ◽

Nickel Catalysts ◽

Organometallic Complex ◽

The One

AbstractIn this paper we present two different techniques for the preparation of single site heterogeneous catalyst. The first method consists in the impregnation of a solution of the organometallic compound in MCM41. The second method intends to establish the in situ synthesis of the complex within the solid’s pores by the reaction of the organic ligand with the metal cation previously introduced in the support. The direct deposition of the organometallic complex in the support resulted in an active catalyst which gives polyethylene with the same microstructure as the one obtained with the related homogeneous systems. The heterogeneous catalysts obtained by reaction of the ligand with the metal already present in the support showed a lower catalytic activity.

Download Full-text

Biodiesel Processing Using Sodium and Potassium Geopolymer Powders as Heterogeneous Catalysts

Molecules ◽

10.3390/molecules25122839 ◽

2020 ◽

Vol 25 (12) ◽

pp. 2839 ◽

Cited By ~ 1

Author(s):

Renata F. Botti ◽

Murilo D.M. Innocentini ◽

Thais A. Faleiros ◽

Murilo F. Mello ◽

Danilo L. Flumignan ◽

...

Keyword(s):

Catalytic Activity ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Heterogeneous Catalysts ◽

Average Pore Size ◽

Thermal Shrinkage ◽

Average Pore ◽

Base Catalysts ◽

Sodium And Potassium

This work investigates the catalytic activity of geopolymers produced using two different alkali components (sodium or potassium) and four treatment temperatures (110 to 700 °C) for the methyl transesterification of soybean oil. The geopolymers were prepared with metakaolin as an aluminosilicate source and alkaline activating solutions containing either sodium or potassium in the same molar oxide proportions. The potassium-based formulation displayed a higher specific surface area and lower average pore size (28.64–62.54 m²/g; 9 nm) than the sodium formulation (6.34–32.62 m²/g; 17 nm). The reduction in specific surface area (SSA) after the heat treatment was more severe for the sodium formulation due to the higher thermal shrinkage. The catalytic activity of the geopolymer powders was compared under the same reactional conditions (70–75 °C, 150% methanol excess, 4 h reaction) and same weight amounts (3% to oil). The differences in performance were attributed to the influences of sodium and potassium on the geopolymerization process and to the accessibility of the reactants to the catalytic sites. The Na-based geopolymers performed better, with FAME contents in the biodiesel phase of 85.1% and 89.9% for samples treated at 500 and 300 °C, respectively. These results are competitive in comparison with most heterogeneous base catalysts reported in the literature, considering the very mild conditions of temperature, excess methanol and catalyst amount and the short time spent in reactions.

Download Full-text

The Roles of the Structure and Basic Sites of Sodium Titanates on Transesterification Reactions to Obtain Biodiesel

Catalysts ◽

10.3390/catal9120989 ◽

2019 ◽

Vol 9 (12) ◽

pp. 989

Author(s):

Josue J. Machorro ◽

Ana L. Lazaro ◽

Fabricio Espejel-Ayala ◽

Eduardo Coutiño-Gonzalez ◽

Juan C. Chavarria-Hernandez ◽

...

Keyword(s):

Catalytic Activity ◽

Heterogeneous Catalysts ◽

Catalytic Performance ◽

Influential Factor ◽

Biodiesel Production ◽

Materials Characterization ◽

Basic Sites ◽

Calcination Temperatures ◽

Input Variables ◽

Associated Species

Sodium titanates were evaluated as heterogeneous catalysts for biodiesel production. Materials were prepared using an experimental design considering NaOH and TiO2 concentrations and hydrothermal and calcination temperatures as input variables. Materials characterization was carried out by DRX-Rietveld refinement, CO2-TPD, and XPS. Statistical analysis of the experimental results indicates that the calcination temperature is the most influential factor in the formation of sodium titanates with high catalytic performance in transesterification reactions. Further analysis of the oil-to-biodiesel conversion revealed that the catalytic activity of sodium titanates is directly correlated to the catalyst associated species and to the density of medium-strong basic sites on the surface of the material, obtaining up to 95% conversion to biodiesel at 60 °C using 3.6% weight catalyst with respect to oil.

Download Full-text

Fabrication of Core-Shell Structural SiO2@H3[PM12O40] Material and Its Catalytic Activity

Journal of Nanomaterials ◽

10.1155/2014/835931 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8

Author(s):

Xin Yang ◽

Junhai Wang ◽

Qi Zhang ◽

Xu Wang ◽

Linlin Xu ◽

...

Keyword(s):

Catalytic Activity ◽

Heterogeneous Catalysts ◽

Sol Gel ◽

Operating Conditions ◽

Core Shell ◽

Catalytic Wet Air Oxidation ◽

Air Oxidation ◽

Wet Air Oxidation ◽

Heterogeneous Catalytic ◽

Room Condition

Through a natural tree grain template and sol-gel technology, the heterogeneous catalytic materials based on polyoxometalate compounds H3[PM12O40] encapsulating SiO2: SiO2@H3[PM12O40] (SiO2@PM12, M = W, Mo) with core-shell structure had been prepared. The structure and morphology of the core-shell microspheres were characterized by the XRD, IR spectroscopy, UV-Vis absorbance, and SEM. These microsphere materials can be used as heterogeneous catalysts with high activity and stability for catalytic wet air oxidation of pollutant dyes safranine T (ST) at room condition. The results show that the catalysts have excellent catalytic activity in treatment of wastewater containing 10 mg/L ST, and 94% of color can be removed within 60 min. Under different cycling runs, it is shown that the catalysts are stable under such operating conditions and the leaching tests show negligible leaching effect owing to the lesser dissolution.

Download Full-text

Heterogeneous catalysis with encapsulated haem and other synthetic porphyrins: Harnessing the power of porphyrins for oxidation reactions

Open Chemistry ◽

10.1515/chem-2018-0083 ◽

2018 ◽

Vol 16 (1) ◽

pp. 763-789 ◽

Cited By ~ 3

Author(s):

Nicola A. Dare ◽

Timothy J. Egan

Keyword(s):

Catalytic Activity ◽

Heterogeneous Catalysis ◽

Heterogeneous Catalysts ◽

Organic Substrates ◽

Oxidation Reactions ◽

Highly Efficient ◽

Protein Environment

AbstractEncapsulated metalloporphyrins have been widely studied for their use as efficient heterogeneous catalysts, inspired by the known catalytic activity of porphyrins in haemoproteins. The oxidation of organic substrates by haemoproteins is one of the well-known roles of these proteins, in which the haem (ferriprotoporphyrin IX = FePPIX) cofactor is the centre of reactivity. While these porphyrins are highly efficient catalysts in the protein environment, once removed, they quickly lose their reactivity. It is for this reason that they have garnered much interest in the field of heterogeneous catalysis of oxidation reactions. This review details current research in the field, focusing on the application of encapsulated haem, and other synthetic metalloporphyrins, applied to oxidation reactions.

Download Full-text