Heterogeneous and solid supported dendrimer catalysts

King, Amy S. H.; Twyman, Lance J.

doi:10.1039/b204207j

Cited by 53 publications

(22 citation statements)

References 42 publications

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“…A method of controlling metal leaching in supported solid catalysis has been proposed by Hunter et al [45] who concluded from their work that stronger bond with the metal complex formed by the inclusion of legands could be controlled leaching of the active phase from a solid catalyst. Other workers [46] have also discussed a similar phenomenon and have suggested that the incorporation of 11. Reusability of KI/g-Al 2 O 3 catalyst in transesterification of palm oil.…”

Section: Catalyst Reusabilitymentioning

confidence: 79%

Biodiesel synthesis over millimetric γ-Al2O3/KI catalyst

Islam

Taufiq‐Yap

Ravindra

et al. 2015

Energy

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a b s t r a c tThe use of spherical millimetric gamma-alumina (g-Al 2 O 3 ) as a catalyst support for the production of biodiesel from palm oil was demonstrated. The catalyst support was produced using dripping method, and KI catalyst was loaded on the support using impregnation method. The highest FAME (fatty acid methyl ester) yield of 98% was obtained when the reaction was carried out under the conditions of catalyst to oil ratio of 0.6 g (4wt.%, g cat. /g oil ) using 0:24 g KI =g gAl2O3 of catalyst loading, reaction time of 4 h, temperature of 60 C and methanol to palm oil molar ratio of 14:1. XRD (X-ray diffraction) analysis showed the formation of K 2 O and KAlO 2 phases on the KI/g-Al 2 O 3 catalyst which were possibly the active sites for the transesterification reaction. The highest number and strength of basic sites generated from the solid phase reaction of the KI/g-Al 2 O 3 catalyst loaded with 0.24 g kF/g g-Al 2 O 3 were confirmed by temperature programmed desorption of CO 2 (CO 2 -TPD) analysis. The nitrogen adsorptionedesorption isotherms was revealed a mesoporous structure of the catalysts. The leaching of potassium species in reused catalysts was observed, as verified by XRF (X-ray fluorescence). KI/g-Al 2 O 3 had a long life time and maintained sustained activity even after being repeatedly used for 11 cycles. The biodiesel yield was comparable to that produced from smaller catalysts. Thus, the catalyst could be potential for industrial use, as they can be handled safely, easily separated from the process fluid and used in fixed bed reactor to minimize pressure drop.

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Section: Catalyst Reusabilitymentioning

confidence: 79%

Biodiesel synthesis over millimetric γ-Al2O3/KI catalyst

Islam

Taufiq‐Yap

Ravindra

et al. 2015

Energy

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“…The results surprisingly showed that the prepared dendritic catalyst (Ce (IV)-G2) was the most effective catalyst for this reaction, and the respective pyrido[3,2-c]coumarin 4be was obtained in higher yield than those of pure Ce (OTf) 4 , HNT, or even Ce(OTf) 4 coated on HNT (Ce (OTf) 4 @HNT). The three variables, solvent, temperature, and the amount of catalyst were investigated (entries [16][17][18][19][20][21][22][23][24][25][26][27]. The best yield of the product was obtained using 80 mg Ce(IV)-G2 catalyst (containing 0.0028 mmol Ce(IV), 0.28 mol%) at 130 C under solvent-free conditions (entry 25).…”

Section: Resultsmentioning

confidence: 99%

“…[20,21] Due to the improvement of the catalytic activity as well as the simplified recyclability of DEMs, heterogenization of DEMs by immobilizing on insoluble supports has gained much interest. [22][23][24][25] During the past years, using organic or inorganic nanotubular materials as support has attracted attention because of their exceptionally large surface area and specific tube-shaped structure with an empty cavity. [26] Halloysite nanotube (HNT), a kind of naturally occurring aluminosilicate nanoclay (Al 2 Si 2 O 5 (OH) 4 Á2H 2 O with 1:1 ratio of Al/Si), [27] has gained great attention because of its widespread applications [28][29][30][31][32][33][34][35] and advantages such as high mechanical and thermal stability, low price, environmental friendliness, biocompatibility, large surface area, resistibility against organic solvents, and ease of reusability.…”

Section: Introductionmentioning

confidence: 99%

Ce(IV) immobilized on halloysite nanotube–functionalized dendrimer (Ce(IV)–G2): A novel and efficient dendritic catalyst for the synthesis of pyrido[3,2‐c]coumarin derivatives

Ataee-Kachouei

Nasr‐Esfahani

Mohammadpoor‐Baltork

et al. 2020

Applied Organom Chemis

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In this study, a new and stable Ce(IV) immobilized on halloysite nanotubefunctionalized dendrimer was designed, synthesized, and characterized using Fourier-transform infrared, elemental analysis, thermogravimetric analysis, field emission scanning electron microscopy, scanning electron microscopyenergy dispersive X-ray spectroscopy, transmission electron microscopy, dynamic light scattering, Brunauer-Emmett-Teller, and inductively coupled plasma optical emission spectroscopy techniques. This catalyst was efficiently used for the one-pot, single-step multicomponent synthesis of pyrido[3,2-c] coumarins from 4-aminocoumarin, aldehydes, and aryl ketones. The efficiency and selectivity of this catalytic system were also evaluated for the synthesis of pyrido[3,2-c]coumarins from terminal/internal alkynes instead of aryl ketones. In this respect, the regioselectivity of the products was successfully assigned by X-ray crystallographic analysis. All these reactions were best performed under solvent-free conditions in the presence of only 0.28 mol% of the catalyst, and such a one-pot multicomponent synthesis of pyrido[3,2-c]coumarins is reported for the first time. It is also worth noting that single-step and short reaction path for the synthesis of a variety of pyrido[3,2-c]coumarins along with excellent reusability of this dendritic catalyst makes this method economically and environmentally attractive.

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“…Besides "conventional" polymers, also dendritic structures have been applied for the immobilization or stabilization of Pd complexes (for review see [107]). Christensen and coworkers used polyamidoamine dendrons (PAMAM) for the encapsulation of Pd(0) nanoparticles [108].…”

Section: Polymers and Dendrimersmentioning

confidence: 99%

Supported Palladium Catalysts in Heck Coupling Reactions - Problems,Potential and Recent Advances

Köhler

Pröckl

Kleist

2006

COC

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The review reports the general approach, problems, potential and recent advances in heterogeneously catalyzed Heck reactions. It demonstrates the advantages and limitations for practical applications at present. A literature overview is given separately for substrates that are easier to activate (aryl iodides, activated aryl bromides) and for non-/deactivated aryl bromides and aryl chlorides during the period between 2001 and 2005. New approaches and strategies for the activation of aryl bromides and especially chlorides by heterogeneous catalysts are discussed. The argumentations clearly exceed simple separation and reuse arguments. Particular attention is given to the relation between homogeneous and heterogeneous catalysis from the mechanistic point of view. Very recent reports show clear success in the understanding of corresponding reaction mechanisms. Palladium species dissolved from the support are proven to be responsible for high activity and selectivity in Heck reactions by supported catalysts (Pd on activated carbon, oxides, polymers and in zeolites). The careful choice of optimum catalyst and reaction conditions are crucial and allowed the development of simple heterogeneous catalysts that activate even deactivated aryl chlorides with high yields within few hours of reaction time.

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Heterogeneous and solid supported dendrimer catalysts

Cited by 53 publications

References 42 publications

Biodiesel synthesis over millimetric γ-Al2O3/KI catalyst

Biodiesel synthesis over millimetric γ-Al2O3/KI catalyst

Ce(IV) immobilized on halloysite nanotube–functionalized dendrimer (Ce(IV)–G2): A novel and efficient dendritic catalyst for the synthesis of pyrido[3,2‐c]coumarin derivatives

Supported Palladium Catalysts in Heck Coupling Reactions - Problems,Potential and Recent Advances

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