scholarly journals Fe3+-Exchanged Titanate Nanotubes: A New Kind of Highly Active Heterogeneous Catalyst for Friedel-Crafts Type Benzylation

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yunchen Du ◽  
Di Guo ◽  
Meiling Xiong ◽  
Yanwu Qi ◽  
Chenkui Cui ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Heterogeneous Catalyst ◽  
Heterogeneous Catalysts ◽  
Catalyst Support ◽  
Environmental Benefits ◽  
Titanate Nanotubes ◽  
Catalytic Activities ◽  
Highly Active ◽  
Active Metal ◽  
Benzylation Of Benzene

Heterogeneous catalysis for Friedel-Crafts type benzylation has received much attention in recent years due to its characteristic of environmental benefits. In this paper, titanate nanotubes (TNTs) were employed as heterogeneous catalyst support, and a new kind of Fe3+-exchanged titanate nanotubes (Fe-TNTs) catalyst with highly dispersed ferric sites was constructed by an ion exchange technique. The obtained catalyst was systematically characterized by XRD, TEM, N2adsorption, XPS, and UV-vis spectra. As expected, Fe-TNTs showed excellent catalytic activities in the benzylation of benzene and benzene derivatives. The recycling tests for Fe-TNTs were also carried out, where the reason for the gradually decreased activity was carefully investigated. Superior to some reported catalysts, the catalytic ability of used Fe-TNTs could be easily recovered by ion exchange again, indicating that Fe-TNTs herein were a highly active and durable heterogeneous catalyst for Friedel-Crafts type benzylation. These results might be helpful for the design and preparation of novel heterogeneous catalysts by combining the structural advantages of titanate nanotubes and active metal ions.

scholarly journals Metal Nanoparticles as Sustainable Tools for C–N Bond Formation via C–H Activation

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4106
Author(s):  
Federica Valentini ◽  
Oriana Piermatti ◽  
Luigi Vaccaro
Keyword(s):  
Metal Nanoparticles ◽  
Natural Product ◽  
Heterogeneous Catalysts ◽  
Organic Molecules ◽  
Bond Formation ◽  
Environmental Costs ◽  
Highly Active ◽  
Active Mechanism ◽  
Active Metal ◽  
Complex Organic

The design of highly active metal nanoparticles to be employed as efficient heterogeneous catalysts is a key tool for the construction of complex organic molecules and the minimization of their environmental costs. The formation of novel C–N bonds via C–H activation is an effective atom-economical strategy to access high value materials in pharmaceuticals, polymers, and natural product production. In this contribution, the literature of the last ten years on the use of metal nanoparticles in the processes involving direct C–N bond formation will be discussed. Where possible, a discussion on the role and influence of the support used for the immobilization and/or the metal chosen is reported. Particular attention was given to the description of the experiments performed to elucidate the active mechanism.

scholarly journals Cleaner Production of Epoxidized Cooking Oil Using A Heterogeneous Catalyst

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1261
Author(s):  
Maria Kurańska ◽  
Magdalena Niemiec
Keyword(s):  
Ion Exchange ◽  
Heterogeneous Catalyst ◽  
Heterogeneous Catalysts ◽  
Ion Exchange Resin ◽  
Solvent Free ◽  
Cooking Oil ◽  
Used Cooking Oil ◽  
Waste Oils ◽  
Free Process ◽  
Dowex 50Wx8

A cleaner solvent-free process of used cooking oil epoxidation has been developed. The epoxidation reactions were carried out using “in situ”-formed peroxy acid. A variety of ion exchange resins with different cross-linking percentages and particle sizes such as Dowex 50WX2 50-100, Dowex 50WX2 100-200, Dowex 50WX2 200-400, Dowex 50WX4 50-100, Dowex 50WX4 100-200, Dowex 50WX4 200-400, Dowex 50WX8 50-100, Dowex 50WX8 100-200, Dowex 50WX8 200-400 were used in the synthesis as heterogeneous catalysts. No significant effect of the size as well as porosity of the catalysts on the properties of the final products was observed. In order to develop a more economically beneficial process, a much cheaper heterogeneous catalyst—Amberlite IR-120—was used and the properties of the epoxidized oil were compared with the bio-components obtained in the reaction catalyzed by the Dowex resins. The epoxidized waste oils obtained in the experiments were characterized by epoxy values in the range of 0.32–0.35 mol/100 g. To reduce the amount of waste, the reusability of the ion exchange resin in the epoxidation reaction was studied. Ten reactions were carried out using the same catalyst and each synthesis was monitored by determination of epoxy value changes vs. time of the reactions. It was noticed that in the case of the reactions where the catalyst was reused for the third and fourth time the content of oxirane rings was higher by 8 and 6%, respectively, compared to the reaction where the catalyst was used only one time. Such an observation has not been reported so far. The epoxidation process with catalyst recirculation is expected to play an important role in the development of a new approach to the environmentally friendly solvent-free epoxidation process of waste oils.

Site-specific catalytic activities to facilitate solvent-free aerobic oxidation of cyclohexylamine to cyclohexanone oxime over highly efficient Nb-modified SBA-15 catalysts

2020 ◽  
Vol 10 (10) ◽  
pp. 3409-3422
Author(s):  
Wei Ding ◽  
Haoyu Peng ◽  
Wenzhou Zhong ◽  
Liqiu Mao ◽  
Dulin Yin
Keyword(s):  
Heterogeneous Catalysts ◽  
Aerobic Oxidation ◽  
Solvent Free ◽  
Cyclohexanone Oxime ◽  
Site Specific ◽  
Catalytic Activities ◽  
Highly Efficient ◽  
Highly Active ◽  
Nitrogen Center ◽  
Highly Sensitive

The development of highly active and selective heterogeneous catalysts for efficient oxidation of cyclohexylamine to cyclohexanone oxime is a challenge associated with the highly sensitive nitrogen center of cyclohexylamine.

Synthesis of carbonate esters by carboxymethylation using NaAlO2 as a highly active heterogeneous catalyst

2018 ◽  
Author(s):  
Sreerangappa Ramesh ◽  
Kiran Indukuri ◽  
Olivier Riant ◽  
Damien Debecker
Keyword(s):  
Heterogeneous Catalyst ◽  
Dimethyl Carbonate ◽  
Sodium Aluminate ◽  
High Yield ◽  
Solid Catalyst ◽  
Highly Active ◽  
Aromatic Alcohols ◽  
Green Conditions ◽  
Mixed Carbonate

<p>Sodium aluminate is presented as a highly active heterogeneous catalyst able to convert a range of alcohols into the corresponding mixed carbonate esters, in high yield and under green conditions. The reaction is carried out using dimethyl carbonate both as a reactant and solvent, at 90°C. Allylic, aliphatic and aromatic alcohols are converted in good yields. The solid catalyst is shown to be truly heterogeneous, resistant to leaching, and recyclable. </p>

The Synthesis and Application of Functionalized Mesoporous Silica SBA-15 as Heterogeneous Catalyst in Organic Synthesis

2020 ◽  
Vol 24 ◽  
Author(s):  
Ghodsi Mohammadi Ziarani ◽  
Shima Roshankar ◽  
Fatemeh Mohajer ◽  
Alireza Badiei
Keyword(s):  
Mesoporous Silica ◽  
Heterogeneous Catalyst ◽  
Organic Synthesis ◽  
Lewis Acid ◽  
Heterogeneous Catalysts ◽  
Organic Transformations ◽  
Functionalized Mesoporous Silica ◽  
Silica Nanomaterials ◽  
Wide Range ◽  
Target Molecules

Abstract:: Mesoporous silica nanomaterials provide an extraordinary advantage for making new and superior heterogeneous catalysts because of their surface silanol groups. The functionalized mesoporous SBA-15, such as acidic, basic, BrÖnsted, lewis acid, and chiral catalysts, are used for a wide range of organic synthesis. The importance of the chiral ligands, which were immobilized on the SBA-15, was mentioned in this review to achieve chiral products as valuable target molecules. Herein, their synthesis and application in different organic transformations are reviewed from 2016 till date 2020.

scholarly journals Immobilization of an Iridium(I)-NHC-Phosphine Catalyst for Hydrogenation Reactions under Batch and Flow Conditions

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 656
Author(s):  
Henrietta Kovács ◽  
Krisztina Orosz ◽  
Gábor Papp ◽  
Ferenc Joó ◽  
Henrietta Horváth
Keyword(s):  
Catalytic Activity ◽  
Ion Exchange ◽  
Heterogeneous Catalyst ◽  
Aqueous Phase ◽  
Levulinic Acid ◽  
Flow Reactor ◽  
High Catalytic Activity ◽  
Flow Conditions ◽  
Hydrogenation Reactions ◽  
Excellent Selectivity

Na2[Ir(cod)(emim)(mtppts)] (1) with high catalytic activity in various organic- and aqueous-phase hydrogenation reactions was immobilized on several types of commercially available ion-exchange supports. The resulting heterogeneous catalyst was investigated in batch reactions and in an H-Cube flow reactor in the hydrogenation of phenylacetylene, diphenylacetylene, 1-hexyne, and benzylideneacetone. Under proper conditions, the catalyst was highly selective in the hydrogenation of alkynes to alkenes, and demonstrated excellent selectivity in C=C over C=O hydrogenation; furthermore, it displayed remarkable stability. Activity of 1 in hydrogenation of levulinic acid to γ-valerolactone was also assessed.

A readily available urea based MOF that act as a highly active heterogeneous catalyst for Friedel-Crafts reaction of indoles and nitrostryenes

2018 ◽  
Vol 104 ◽  
pp. 123-127 ◽  
Author(s):  
Chengfeng Zhu ◽  
Qingqing Mao ◽  
De Li ◽  
Changda Li ◽  
Yiyang Zhou ◽  
...  
Keyword(s):  
Heterogeneous Catalyst ◽  
Highly Active

Laser electrodispersion as a new chlorine-free method for the production of highly effective metal-containing supported catalysts

2012 ◽  
Vol 84 (3) ◽  
pp. 495-508 ◽  
Author(s):  
Ekaterina S. Lokteva ◽  
Anton A. Peristyy ◽  
Natalia E. Kavalerskaya ◽  
Elena V. Golubina ◽  
Lada V. Yashina ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Stability ◽  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Promising Technique ◽  
Wet Impregnation ◽  
Oxide Supports ◽  
Highly Active ◽  
Specific Catalytic Activity ◽  
Free Metal

Laser electrodispersion (LED) of metals is a promising technique for the preparation of heterogeneous catalysts as an alternative to wet impregnation of supports with the corresponding salt solutions. The LED technique can be used to deposit highly active chloride- and nitrate-free metal nanoparticles onto carbon or oxide supports. We report preparation and properties of new Ni-, Pd-, and Au-containing alumina-supported catalysts with low metal loadings (10–3–10–4 % mass) and their comparison with the previously studied carbon (Sibunit) supported systems. The catalysts demonstrate high stability and extremely high specific catalytic activity (by 2–3 orders of magnitude higher than for traditional catalysts) in the gas-phase hydrodechlorination (HDC) of chlorobenzene (CB).

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