Alkaline-doped multiwall carbon nanotubes as efficient catalysts for the Knoevenagel condensation

Delgado-Gómez, F.J.; Casilda, Vanesa Calvino; Cerpa-Naranjo, Arisbel; Cervantes, María Luisa Rojas

doi:10.1016/j.mcat.2017.09.016

Cited by 14 publications

(8 citation statements)

References 49 publications

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“…The multiwall carbon nanotubes (named as CNT herein) used as pristine material for the synthesis of the catalysts were provided by Sigma-Aldrich, with the following characteristics: OD × L 6-9 nm × 5 µm and purity > 95%. They were previously functionalized by oxidation with nitric acid, to obtain the CNT-O sample, according to the procedure described in [28]. The commercial carbon nanotubes used as raw material contained CoCu 2 Sn as an impurity.…”

Section: Preparation Of Samplesmentioning

confidence: 99%

“…The commercial carbon nanotubes used as raw material contained CoCu 2 Sn as an impurity. However, it was mostly removed after treatment with nitric acid [28]. Then, 500 mg of carboxylated multiwalled carbon nanotubes (CNT-O) were stirred in a mixture of 120 mL of thionyl chloride (SOCl 2 ) and 3 mL of dimethylformamide (DMF) at 75 • C for 24 h. After the acyl chlorination, the nanotubes were filtered and washed with anhydrous tetrahydrofuran (THF) several times and dried at room temperature for 24 h. This sample was named as CNT-OCl.…”

Section: Preparation Of Samplesmentioning

confidence: 99%

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Amino-Functionalized Multiwall Carbon Nanotubes as Efficient Basic Catalysts for the Formation of γ-Lactams: Synthesis of N-1-Heptenyl-2-pyrrolidinone

2022

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In this work, we prepared a series of N-functionalized carbon nanotubes by means of a process of acylation-amidation of commercial multiwall carbon nanotubes that were previously pre-oxidized with nitric acid. Three different amines, butylamine, N,N-dimethyl ethylenediamine, and ethylenediamine, were used in the process. The characterization of samples by several techniques probed the incorporation of nitrogen atoms to the carbon nanotubes, especially in the case of ethylenediamine. The solids were tested as catalysts in the synthesis of N-1-heptenyl-2-pyrrolidinone, included in the group of a γ-lactams, compounds that show important biological properties. The most active catalyst was that prepared with butylamine, which exhibited the highest SBET and Vpore values and contained an amount of nitrogen that was intermediate between that of the other two catalysts. A yield of 60% to N-1-heptenyl-2-pyrrolidinone was achieved after 3 h at 120 °C under free-solvent conditions. This catalyst could be used in four consecutive cycles without significant activity loss.

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Section: Preparation Of Samplesmentioning

confidence: 99%

Section: Preparation Of Samplesmentioning

confidence: 99%

Amino-Functionalized Multiwall Carbon Nanotubes as Efficient Basic Catalysts for the Formation of γ-Lactams: Synthesis of N-1-Heptenyl-2-pyrrolidinone

2022

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“…The commercial pristine multiwalled carbon nanotubes were provided by Sigma-Aldrich (Sigma-Aldrich-Merck, Madrid, Spain) (OD × L 6-9 mm × 5 µm and purity > 95%). They were previously functionalized by oxidation with nitric acid, according to the procedure described in [36]. The commercial carbon nanotubes used as raw material showed CoCu 2 Sn as impurity.…”

Section: Preparation Of the Fe-cu Doped Carbon Nanotubesmentioning

confidence: 99%

“…The commercial carbon nanotubes used as raw material showed CoCu 2 Sn as impurity. However, it was removed after treatment with nitric acid in [36]. The oxidized carbon nanotubes (CNTO) were crushed and sieved to a 0.05 < d < 0.10 mm particle size, and then they were treated with iron and/or copper acetates by the incipient wetness impregnation method.…”

Section: Preparation Of the Fe-cu Doped Carbon Nanotubesmentioning

confidence: 99%

Fe-Cu Doped Multiwalled Carbon Nanotubes for Fenton-like Degradation of Paracetamol Under Mild Conditions

et al. 2020

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A series of carbon nanotubes doped with Fe and/or Cu, Fe100−xCux/CNT (x = 0, 25, 50, 75 and 100) has been prepared by an easy method of wetness impregnation of commercial multiwalled carbon nanotubes previously oxidized with nitric acid. The wide characterization of the solids by different techniques demonstrates that the incorporation of Fe and Cu to the CNTs has been successfully produced. Fe100−xCux/CNT samples were tested as catalysts in the removal of paracetamol from aqueous solution by a combined process of adsorption and Fenton-like oxidation. Under mild conditions, 25 °C and natural pH of solution, i.e., nearly neutral, values of oxidation of paracetamol between 90.2% and 98.3% were achieved after 5 h of reaction in most of cases. Furthermore, with the samples containing higher amounts of copper, i.e., Cu100/CNT and Fe25Cu75/CNT, only 2 h were necessary to produce depletion values of 73.2% and 87.8%, respectively. The influence of pH and dosage of H2O2 on the performance has also been studied. A synergic effect between both Cu+/Cu2+ and Fe2+/Fe3+ in Fenton-like reaction was observed. These results demonstrate that Fe100−xCux/CNT are powerful Fenton-like catalyst for degradation of paracetamol from aqueous solution and they could be extended to the removal of other organic pollutants.

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“…Then, carbanion attacked the carbonyl group of benzaldehyde forming the intermediate 3 . The O – in intermediate 3 combined with conjugate acid 2 to form H 2 O, while intermediate 3 could produce the target product 4 …”

Section: Proposed Mechanism For Knoevenagel Reactionmentioning

confidence: 99%

Sodium Tungstate Supported on a Three‐dimensional and Networked SBA‐15 for Knoevenagel Reaction

2019

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Sodium tungstate (ST) supported on a three-dimensional and networked SBA-15 (3D-SBA-15) was utilized as a novel efficient catalyst for the Knoevenagel condensation of aldehydes with active methylene compounds such as malononitrile and ethyl cyanoacetate to afford substituted olefins through the conventional magnetic stirring or under ultrasound irradiation. ST/3D-SBA-15 catalyst was prepared using an incipient wetness impregnation method and confirmed by series of characterizations such as Fourier-transform infrared spectra (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), N 2 adsorption-desorption and inductively coupled plasma-optical emission spectroscopy. The reaction proceeded smoothly under the both stirring and ultrasound-assisted conditions at room temperature. The 30ST/3D-SBA-15 catalyst with 30 wt% loading of Na 2 WO 4 showed the highest catalytic performance with excellent yield within short time, and improvements were observed by carrying out the reactions under ultrasound irradiation. In addition, the solvent effect was significant in this work, and the optimum solvent was ethanol and water with volume ratio of 1 : 1.

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Alkaline-doped multiwall carbon nanotubes as efficient catalysts for the Knoevenagel condensation

Cited by 14 publications

References 49 publications

Amino-Functionalized Multiwall Carbon Nanotubes as Efficient Basic Catalysts for the Formation of γ-Lactams: Synthesis of N-1-Heptenyl-2-pyrrolidinone

Amino-Functionalized Multiwall Carbon Nanotubes as Efficient Basic Catalysts for the Formation of γ-Lactams: Synthesis of N-1-Heptenyl-2-pyrrolidinone

Fe-Cu Doped Multiwalled Carbon Nanotubes for Fenton-like Degradation of Paracetamol Under Mild Conditions

Sodium Tungstate Supported on a Three‐dimensional and Networked SBA‐15 for Knoevenagel Reaction

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