Platinum and cobalt intermetallic nanoparticles confined within MIL-101(Cr) for enhanced selective hydrogenation of the carbonyl bond in α,β-unsaturated aldehydes: synergistic effects of electronically modified Pt sites and Lewis acid sites

2021 ◽  
Author(s):  
Muhammad Zahid ◽  
Jiang Li ◽  
Ahmed Ismail ◽  
Francisco Zaera ◽  
Yujun Zhu
Keyword(s):  
Synergistic Effect ◽  
Reduction Method ◽  
Synergistic Effects ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Unsaturated Aldehydes ◽  
Uniform Dispersion ◽  
Carbonyl Bond ◽  
Method Show ◽  
Intermetallic Nanoparticles

PtCo/MIL-101(Cr) with high uniform dispersion Pt–Co IMNs synthesized by a polyol reduction method show higher activity for selective catalytic hydrogenation of α,β-unsaturated aldehydes due to the synergistic effect of PtCo and MIL-101(Cr) support.

Direct synthesis of alkynylphosphonates from alkynes and phosphite esters catalyzed by Cu/Cu2O nanoparticles supported on Nb2O5

2018 ◽  
Vol 42 (16) ◽  
pp. 13957-13962 ◽  
Author(s):  
Tao Yuan ◽  
Fei Chen ◽  
Guo-ping Lu
Keyword(s):  
Lewis Acid ◽  
Synergistic Effects ◽  
Copper Catalyst ◽  
Direct Synthesis ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Strong Lewis Acid ◽  
Cu2o Nanoparticles

A new, recyclable and efficient copper catalyst for cross-couplings of alkynes and phosphite esters has been disclosed, in which the synergistic effects of Nb2O5 on the catalyst are found owing to its strong Lewis acid sites.

Aminoethylimidazole ionic liquid grafted MIL-101-NH2 heterogeneous catalyst for conversion of CO2 and epoxide without solvent and cocatalyst

2021 ◽  
Author(s):  
Chenglong Bao ◽  
Yichen Jiang ◽  
Liyan Zhao ◽  
Dazhi Li ◽  
Ping Xu ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ionic Liquid ◽  
Lewis Acid ◽  
Ring Opening ◽  
Synergistic Effects ◽  
Acid Sites ◽  
Epoxide Ring ◽  
Hydrogen Bond Donor ◽  
Lewis Acid Sites ◽  
Epoxide Ring Opening

Besides the activation of CO2 by Lewis basic groups, the synergistic effects of Lewis acid sites (or hydrogen bond donor) together with halogen nucleophilic anions to activate epoxide ring opening...

Nanocrystalline Rhenium-doped TiO2: an efficient catalyst in the one-pot conversion of carbohydrates into levulinic acid. The synergistic effect between Brønsted and Lewis acid sites

2021 ◽  
Author(s):  
Sorin Avramescu ◽  
Cristian D. Ene ◽  
Madalina Ciobanu ◽  
Josefine Schnee ◽  
François Devred ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Synergistic Effect ◽  
Lewis Acid ◽  
Levulinic Acid ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
One Pot ◽  
Efficient Catalyst ◽  
The One ◽  
Brønsted And Lewis Acid

Catalytic activity of TiO2, 2%Re-TiO2 and 10%Re-TiO2 in the conversion of carbohydrates into levulinic acid under autoclave conditions was evaluated. These materials were prepared by aerogel method and characterized by...

scholarly journals Glucose Conversion into 5-Hydroxymethylfurfural over Niobium Oxides Supported on Natural Rubber-Derived Carbon/Silica Nanocomposite

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 887
Author(s):  
Rujeeluk Khumho ◽  
Satit Yousatit ◽  
Chawalit Ngamcharussrivichai
Keyword(s):  
Natural Rubber ◽  
Lewis Acid ◽  
Value Added ◽  
Acid Sites ◽  
Superior Performance ◽  
Lewis Acidity ◽  
Lewis Acid Sites ◽  
Niobium Oxides ◽  
Silica Nanocomposite ◽  
Loading Amount

5-Hydroxymethylfurfural (HMF) is one of the most important lignocellulosic biomass-derived platform molecules for production of renewable fuel additives, liquid hydrocarbon fuels, and value-added chemicals. The present work developed niobium oxides (Nb2O5) supported on mesoporous carbon/silica nanocomposite (MCS), as novel solid base catalyst for synthesis of HMF via one-pot glucose conversion in a biphasic solvent. The MCS material was prepared via carbonization using natural rubber dispersed in hexagonal mesoporous silica (HMS) as a precursor. The Nb2O5 supported on MCS (Nb/MCS) catalyst with an niobium (Nb) loading amount of 10 wt.% (10-Nb/MCS) was characterized by high dispersion, and so tiny crystallites of Nb2O5, on the MCS surface, good textural properties, and the presence of Bronsted and Lewis acid sites with weak-to-medium strength. By varying the Nb loading amount, the crystallite size of Nb2O5 and molar ratio of Bronsted/Lewis acidity could be tuned. When compared to the pure silica HMS-supported Nb catalyst, the Nb/MCS material showed a superior glucose conversion and HMF yield. The highest HMF yield of 57.5% was achieved at 93.2% glucose conversion when using 10-Nb/MCS as catalyst (5 wt.% loading with respect to the mass of glucose) at 190 °C for 1 h. Furthermore, 10-Nb/MCS had excellent catalytic stability, being reused in the reaction for five consecutive cycles during which both the glucose conversion and HMF yield were insignificantly changed. Its superior performance was ascribed to the suitable ratio of Brønsted/Lewis acid sites, and the hydrophobic properties generated from the carbon moieties dispersed in the MCS nanocomposite.

On the nature of framework Brønsted and Lewis acid sites in ZSM-5

Zeolites ◽  
1997 ◽  
Vol 19 (4) ◽  
pp. 288-296 ◽  
Author(s):  
G.L. Woolery ◽  
G.H. Kuehl ◽  
H.C. Timken ◽  
A.W. Chester ◽  
J.C. Vartuli
Keyword(s):  
Lewis Acid ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Brønsted And Lewis Acid
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