scholarly journals Selective Catalytic Transfer Hydrogenolysis of Glycerol to 2-Isopropoxy-Propan-1-Ol over Noble Metal Ion-Exchanged Mordenite Zeolite

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 885 ◽  
Author(s):  
Bhupendra Kumar Singh ◽  
Yongseok Kim ◽  
Seungdon Kwon ◽  
Kyungsu Na
Keyword(s):  
Noble Metal ◽  
Metal Ion ◽  
Heterogeneous Catalysts ◽  
Initial Pressure ◽  
Catalytic Reactions ◽  
Single Product ◽  
Coupling Reagent ◽  
Catalytic Transfer ◽  
Reactive Coupling ◽  
By Products

This study investigated the selective conversion of glycerol to 2-isopropoxy-propan-1-ol over noble metal ion-exchanged mordenite zeolites (RuMOR, RhMOR, and PdMOR) as heterogeneous catalysts via catalytic transfer hydrogenolysis (CTH) using propan-2-ol as the solvent, hydrogen supplier, and reactive coupling reagent with glycerol. The catalytic reactions were performed at 140 °C under inert conditions with a 0.5 MPa initial pressure of N2. A single product, 2-isopropoxy-propan-1-ol, was catalytically generated without any appreciable by-products. The catalytic results were reproducible, and the catalysts exhibited good recyclability.

Photocatalytic Activities of Noble Metal Ion Doped SrTiO3under Visible Light Irradiation

2004 ◽  
Vol 108 (26) ◽  
pp. 8992-8995 ◽  
Author(s):  
Ryoko Konta ◽  
Tatsuya Ishii ◽  
Hideki Kato ◽  
Akihiko Kudo
Keyword(s):  
Visible Light ◽  
Noble Metal ◽  
Visible Light Irradiation ◽  
Metal Ion ◽  
Light Irradiation ◽  
Photocatalytic Activities

Investigations of the key macrolactamisation step in the synthesis of cyclic tetrapeptide pseudoxylallemycin A

2019 ◽  
Vol 17 (16) ◽  
pp. 3902-3913
Author(s):  
Alan J. Cameron ◽  
Christopher J. Squire ◽  
Ashley Gérenton ◽  
Louise A. Stubbing ◽  
Paul W. R. Harris ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Coupling Reagent ◽  
By Products ◽  
Unstable Intermediate ◽  
Cyclic Tetrapeptide

During total synthesis of pseudoxylallemycin A, an unstable intermediate was observed and appeared to be reactivated by coupling reagent by-products.

scholarly journals Depolymerization of Poly(ethylene terephthalate) Wastes through Glycolysis using Lewis Acidic Bentonite Catalysts

2019 ◽  
Vol 32 (1) ◽  
pp. 187-191
Author(s):  
Gopal Jeya ◽  
Murugan Anbarasu ◽  
Ravikumar Dhanalakshmi ◽  
Viswanathan Vinitha ◽  
Vajiravelu Sivamurugan
Keyword(s):  
Metal Ion ◽  
Heterogeneous Catalysts ◽  
Ethylene Terephthalate ◽  
Nitrogen Adsorption ◽  
Impregnation Method ◽  
Wet Impregnation ◽  
Poly Ethylene Terephthalate ◽  
Acidic Nature ◽  
Poly Ethylene ◽  
Optimized Conditions

In the present investigation, the authors explored the depolymerization of waste poly(ethylene terephthalate) (PET) beverage bottles using glycolysis (transesterification) catalyzed by Al3+, Fe3+ and Zn2+ impregnated bentonite catalysts. Heterogeneous catalysts such as clay, zeolite, alumina etc. preferred over homogeneous catalysts, thus we focused on the development of solid acid catalysts based on economically viable clay catalysts. The desired Lewis acidic nature was introduced by wet impregnation method at variable metal ion to clay ratio such as 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 wt. %. The effect of metal-ion loading on the surface area, pore volume and crystalline nature of the bentonite has been evaluated by nitrogen adsorption and desorption studies and XRD. The PET wastes collected from post-consumer beverage bottles were depolymerized using ethylene glycol as a glycolyting agent afforded bis(2-hydroxy ethyl)terephthalate (BHET) in 85-90 % yield under optimized conditions. The yield of BHET was observed to be increasing with increase in Lewis acidic metal ions loading from 0.5 to 4.0 wt. % as well as increase in catalysts to PET ratio. Among the catalysts, Al3+ and Zn2+-bentonite catalysts showed higher yield of BHET up to 90 % at 4 and 5 wt. % loading of metal-ion.

scholarly journals Plasmon-Induced Electrocatalysis with Multi-Component Nanostructures

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 43 ◽  
Author(s):  
Palaniappan Subramanian ◽  
Dalila Meziane ◽  
Robert Wojcieszak ◽  
Franck Dumeignil ◽  
Rabah Boukherroub ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Charge Carriers ◽  
Catalytic Reactions ◽  
Synthetic Methods ◽  
Metal Nanostructures ◽  
Electron Hole ◽  
Catalytic Systems ◽  
Electrochemical Catalysis ◽  
Electrochemically Active ◽  
Shed Light

Noble metal nanostructures are exceptional light absorbing systems, in which electron–hole pairs can be formed and used as “hot” charge carriers for catalytic applications. The main goal of the emerging field of plasmon-induced catalysis is to design a novel way of finely tuning the activity and selectivity of heterogeneous catalysts. The designed strategies for the preparation of plasmonic nanomaterials for catalytic systems are highly crucial to achieve improvement in the performance of targeted catalytic reactions and processes. While there is a growing number of composite materials for photochemical processes-mediated by hot charge carriers, the reports on plasmon-enhanced electrochemical catalysis and their investigated reactions are still scarce. This review provides a brief overview of the current understanding of the charge flow within plasmon-enhanced electrochemically active nanostructures and their synthetic methods. It is intended to shed light on the recent progress achieved in the synthesis of multi-component nanostructures, in particular for the plasmon-mediated electrocatalysis of major fuel-forming and fuel cell reactions.

Selective Catalytic Reduction of NOx: Mechanistic Perspectives on the Role of Base Metal and Noble Metal Ion Substitution

2008 ◽  
Vol 47 (23) ◽  
pp. 9240-9247 ◽  
Author(s):  
Sounak Roy ◽  
A. Marimuthu ◽  
Parag A. Deshpande ◽  
M. S. Hegde ◽  
Giridhar Madras
Keyword(s):  
Selective Catalytic Reduction ◽  
Base Metal ◽  
Noble Metal ◽  
Metal Ion ◽  
Catalytic Reduction ◽  
Ion Substitution ◽  
Reduction Of Nox

Catalytic Properties of Cryogelated Noble Metal Aerogels

2017 ◽  
Vol 231 (1) ◽  
Author(s):  
Axel Freytag ◽  
Massimo Colombo ◽  
Nadja C. Bigall
Keyword(s):  
Noble Metal ◽  
Room Temperature ◽  
Catalyst Surface ◽  
Catalytic Properties ◽  
State Of The Art ◽  
Catalytic Performance ◽  
Model Reaction ◽  
Catalytic Reactions ◽  
Co Conversion ◽  
Oxidation Of Carbon Monoxide

AbstractThe catalytic properties of cryogelated noble metal aerogel monoliths out of aqueous colloids are investigated using the oxidation of carbon monoxide (CO) as a model reaction, in order to evaluate their potential for catalytic applications. Aerogels built of self-supporting platinum (Pt) and palladium (Pd) nanocrystals (NCs) have a directly accessible catalyst surface and show catalytic performance similar to state of the art catalysts while being support-free and therefore ultralight materials. In addition, these materials provide properties like room temperature CO conversion and spontaneous catalytic reactions. However, full material aerogel catalysts come with the side effect of limited thermal stability, which will have to be overcome in future.

Hollow Ag/carbon microporous spheres with high catalytic activity based on a bio-inspiration polydopamine reaction platform

RSC Advances ◽  
2015 ◽  
Vol 5 (110) ◽  
pp. 91056-91061 ◽  
Author(s):  
Qian Zhang ◽  
Chen Zhou ◽  
Aisheng Huang
Keyword(s):  
Catalytic Activity ◽  
Noble Metal ◽  
Metal Catalysts ◽  
Catalytic Reactions ◽  
High Catalytic Activity ◽  
Noble Metal Catalysts

Based on polydopamine reaction platform, hollow Ag/carbon microporous spheres with high catalytic activity were prepared through a template-assisted method, which is promising to replace other noble metal catalysts in metal catalytic reactions.

scholarly journals Zinc- and Copper-Loaded Nanosponges from Cellulose Nanofibers Hydrogels: New Heterogeneous Catalysts for the Synthesis of Aromatic Acetals

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 54
Author(s):  
Laura Riva ◽  
Angelo Davide Lotito ◽  
Carlo Punta ◽  
Alessandro Sacchetti
Keyword(s):  
Organic Synthesis ◽  
Metal Ion ◽  
Heterogeneous Catalysts ◽  
Water Solution ◽  
Cellulose Nanofibers ◽  
Reaction Medium ◽  
Emission Spectrometry ◽  
Icp Oes ◽  
Ion Release ◽  
Metal Ion Release

Herein we report the synthesis of cellulose-based metal-loaded nano-sponges and their application as heterogeneous catalysts in organic synthesis. First, the combination in water solution of TEMPO-oxidized cellulose nanofibers (TOCNF) with branched polyethyleneimine (bPEI) and citric acid (CA), and the thermal treatment of the resulting hydrogel, leads to the synthesis of an eco-safe micro- and nano-porous cellulose nano-sponge (CNS). Subsequently, by exploiting the metal chelation characteristics of CNS, already extensively investigated in the field of environmental decontamination, this material is successfully loaded with Cu (II) or Zn (II) metal ions. Efficiency and homogeneity of metal-loading is confirmed by scanning electron microscopy (SEM) analysis with an energy dispersive X-ray spectroscopy (EDS) detector and by inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis. The resulting materials perform superbly as heterogeneous catalysts for promoting the reaction between aromatic aldehydes and alcohols in the synthesis of aromatic acetals, which play a fundamental role as intermediates in organic synthesis. Optimized conditions allow one to obtain conversions higher than 90% and almost complete selectivity toward acetal products, minimizing, and in some cases eliminating, the formation of carboxylic acid by-products. ICP-OES analysis of the reaction medium allows one to exclude any possible metal-ion release, confirming that catalysis undergoes under heterogeneous conditions. The new metal-loaded CNS can be re-used and recycled five times without losing their catalytic activity.

Sign in / Sign up

Export Citation Format

Share Document