scholarly journals Metal–salen molecular cages as efficient and recyclable heterogeneous catalysts for cycloaddition of CO2 with epoxides under ambient conditions

2019 ◽  
Vol 10 (5) ◽  
pp. 1549-1554 ◽  
Author(s):  
Chee Koon Ng ◽  
Ren Wei Toh ◽  
Ting Ting Lin ◽  
He-Kuan Luo ◽  
T. S. Andy Hor ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Ambient Conditions ◽  
Molecular Cages ◽  
Full Conversion

Metal-salen molecular cages are efficient and recyclable heterogeneous catalysts for cycloaddition of CO2, achieving full conversion at ambient conditions.

A π-electronic covalent organic framework catalyst: π-walls as catalytic beds for Diels–Alder reactions under ambient conditions

2015 ◽  
Vol 51 (50) ◽  
pp. 10096-10098 ◽  
Author(s):  
Yang Wu ◽  
Hong Xu ◽  
Xiong Chen ◽  
Jia Gao ◽  
Donglin Jiang
Keyword(s):  
Heterogeneous Catalysts ◽  
Diels Alder ◽  
Covalent Organic Frameworks ◽  
Ambient Conditions ◽  
Covalent Organic Framework ◽  
Organic Framework

Covalent organic frameworks were developed as heterogeneous catalysts to explore their π-walls as catalytic beds that enabled Diels–Alder reactions under ambient conditions.

Metalated porous porphyrin polymers as efficient heterogeneous catalysts for cycloaddition of epoxides with CO2 under ambient conditions

2016 ◽  
Vol 338 ◽  
pp. 202-209 ◽  
Author(s):  
Zhifeng Dai ◽  
Qi Sun ◽  
Xiaolong Liu ◽  
Chaoqun Bian ◽  
Qinming Wu ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Ambient Conditions ◽  
Porphyrin Polymers

State-of-the-Art Aluminum Porphyrin-based Heterogeneous Catalysts for the Chemical Fixation of CO2into Cyclic Carbonates at Ambient Conditions

ChemCatChem ◽  
2017 ◽  
Vol 9 (5) ◽  
pp. 767-773 ◽  
Author(s):  
Yaju Chen ◽  
Rongchang Luo ◽  
Qihang Xu ◽  
Wuying Zhang ◽  
Xiantai Zhou ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
State Of The Art ◽  
Chemical Fixation ◽  
Cyclic Carbonates ◽  
Ambient Conditions

scholarly journals Catalytic activation of ethylene C-H bonds on uniform d8 Ir(I) and Ni(II) cations in zeolites: toward molecular level understanding of ethylene polymerization on heterogeneous catalysts

2019 ◽  
Author(s):  
Nicholas R. Jaegers ◽  
Konstantin Khivantsev ◽  
Libor Kovarik ◽  
Dan Klaus ◽  
Jian Zhi Hu ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Molecular Level ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Catalytic Activation ◽  
Dehydrogenative Coupling ◽  
Ethylene Conversion ◽  
Active Metal ◽  
First Time

<div> <p>The homolytic activation of the strong C-H bonds in ethylene is demonstrated, for the first time, on d<sup>8</sup> Ir(I) and Ni(II) single atoms in the cationic positions of zeolites H-FAU and H-BEA under ambient conditions. The oxidative addition of C<sub>2</sub>H<sub>4</sub> to the metal center occurs with the formation of a d<sup>6</sup> metal vinyl hydride, explaining the initiation of the Cossee-Arlman cycle on d<sup>8</sup> M(I/II) sites in the absence of pre-existing M-H bonds. Under mild reaction conditions (80-220ᵒC, 1 bar), the catalytic dimerization to butenes and dehydrogenative coupling of ethylene to butadiene occurs over these catalysts. Butene-1 is not converted to butadiene under the reaction conditions applied. Post-reaction characterization of the two materials reveals that the active metal cations remain site-isolated whereas deactivation occurs due to the formation of carbonaceous deposits on the zeolites. Our findings have significant implications for the molecular level understanding of ethylene conversion and the development of new ways to functionalize C-H bonds under mild conditions.</p> </div>

Aerobic Oxidative Coupling of Aniline Catalyzed by One-Dimensional Manganese Hydroxide Nanomaterials

Synlett ◽  
2019 ◽  
Vol 30 (05) ◽  
pp. 552-556
Author(s):  
Hui Miao ◽  
Kelong Ma ◽  
Shiwei Hu ◽  
Ruiqian Li ◽  
Lin Sun ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Oxidative Coupling ◽  
Heterogeneous Catalysts ◽  
Azo Compounds ◽  
Organic Chemical ◽  
Ambient Conditions ◽  
One Dimensional ◽  
Aromatic Azo Compounds ◽  
Activation Of Oxygen ◽  
Organic Chemical Industry

The aerobic oxidative coupling of aniline is an effective process for producing aromatic azo compounds, which are widely used in the organic chemical industry. The development of heterogeneous catalysts for this reaction would be advantageous because of their recyclability and convenience in posttreatment. In this work, one-dimensional Mn(OH)2 nanostructure with various shapes were synthesized through the adjustment of various surfactants. The as-synthesized Mn(OH)2 nanobelts and nanowires showed superior catalytic activity in the activation of oxygen and aniline. Aromatic azo compounds with a variety of substituents were produced through the coupling of the corresponding anilines without additives under ambient conditions.

scholarly journals Double role of metalloporphyrins in catalytic bioinspired supramolecular metal–organic frameworks (SMOFs)

IUCrJ ◽  
2018 ◽  
Vol 5 (5) ◽  
pp. 559-568
Author(s):  
Arkaitz Fidalgo-Marijuan ◽  
Eder Amayuelas ◽  
Gotzone Barandika ◽  
Edurne S. Larrea ◽  
Begoña Bazán ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Heterogeneous Catalysts ◽  
Metal Organic Frameworks ◽  
Cascade Reactions ◽  
Structural Features ◽  
Microwave Assisted Synthesis ◽  
Great Effort ◽  
Ambient Conditions ◽  
One Pot ◽  
Metal Organic

Heterogeneous catalysts are of great interest in many industrial processes for environmental reasons and, during recent years, a great effort has been devoted to obtain metal–organic frameworks (MOFs) with improved catalytic behaviour. Few supramolecular metal–organic frameworks (SMOFs) are stable under ambient conditions and those with anchored catalysts exhibit favourable properties. However, this paper presents an innovative approach that consists of using metal nodes as both structural synthons and catalysts. Regarding the latter, metalloporphyrins are suitable candidates to play both roles simultaneously. In fact, there are a number of papers that report coordination compounds based on metalloporphyrins exhibiting these features. Thus, the aim of this bioinspired work was to obtain stable SMOFs (at room temperature) based on metalloporphyrins and explore their catalytic activity. This work reports the environmentally friendly microwave-assisted synthesis and characterization of the compound [H(bipy)]2[(MnTPPS)(H2O)2]·2bipy·14H2O (TPPS = meso-tetraphenylporphine-4,4′,4′′,4′′′-tetrasulfonic acid and bipy = 4,4′-bipyridine). This compound is the first example of an MnTPPS-based SMOF, as far as we are aware, and has been structurally and thermally characterized through single-crystal X-ray diffraction, IR spectroscopy, thermogravimetry and transmission electron microscopy. Additionally, this work explores not only the catalytic activity of this compound but also of the compounds μ-O-[FeTCPP]2·16DMF and [CoTPPS0.5(bipy)(H2O)2]·6H2O. The structural features of these supramolecular materials, with accessible networks and high thermal stability, are responsible for their excellent behaviour as heterogeneous catalysts for different oxidation, condensation (aldol and Knoevenagel) and one-pot cascade reactions.

Manganese porphyrin immobilized on montmorillonite: a highly efficient and reusable catalyst for the aerobic epoxidation of olefins under ambient conditions

2012 ◽  
Vol 16 (09) ◽  
pp. 1032-1039 ◽  
Author(s):  
Xiantai Zhou ◽  
Hongbing Ji
Keyword(s):  
Heterogeneous Catalysts ◽  
Catalytic Efficiency ◽  
Nitrogen Adsorption ◽  
Significant Loss ◽  
Basal Spacing ◽  
Reusable Catalyst ◽  
Ambient Conditions ◽  
Manganese Porphyrin ◽  
Highly Efficient ◽  
Epoxidation Of Olefins

Highly efficient aerobic epoxidation of olefins catalyzed by cationic meso-tetrakis-(1-methyl-4-pyridyl) (TM4PyP) metalloporphyrins immobilized into montmorillonite (MT) interlayer was achieved. The heterogeneous catalysts were characterized by diffuse reflectance UV spectra, infrared, X-ray diffraction, nitrogen adsorption isotherm and scanning electron microscopy. Manganese porphyrin (MnTM4PyP-MT) showed excellent activity and selectivity for the aerobic epoxidation of olefins under ambient conditions, in which more 90% yields of epoxides were obtained. The clay basal spacing played significant role in the catalytic efficiency and selectivity for different olefins. The catalyst could be reused consecutively five times without significant loss of activity.

scholarly journals Hollow PdAg-CeO2 heterodimer nanocrystals as highly structured heterogeneous catalysts

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Javier Patarroyo ◽  
Jorge A. Delgado ◽  
Florind Merkoçi ◽  
Aziz Genç ◽  
Guillaume Sauthier ◽  
...  
Keyword(s):  
Beneficial Effect ◽  
Selective Hydrogenation ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalytic Properties ◽  
Reaction Times ◽  
Catalytic Performance ◽  
Internal Alkynes ◽  
First Time ◽  
Full Conversion

AbstractIn the present work, hollow PdAg-CeO2 heterodimer nanocrystals (NCs) were prepared and tested as catalysts for the selective hydrogenation of alkynes. These nanostructures combine for the first time the beneficial effect of alloying Pd with Ag in a single NC hollow domain with the formation of active sites at the interface with the CeO2 counterpart in an additive manner. The PdAg-CeO2 NCs display excellent alkene selectivity for aliphatic alkynes. For the specific case of hydrogenation of internal alkynes such as 4-octyne, very low over-hydrogenation and isomerization products were observed over a full conversion regime, even after prolonged reaction times. These catalytic properties were remarkably superior in comparison to standard catalysts. The promotion of Ag on the moderation of the reactivity of the Pd phase, in combination with the creation of interfacial sites with the CeO2 moiety in the same nanostructure, is pointed as the responsible of such a remarkable catalytic performance.

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