Sulfonated multiwalled carbon nanotubes (MWCNTs) as a new, efficient, and recyclable heterogeneous nanocatalyst for the synthesis of amines

2012 ◽  
Vol 90 (8) ◽  
pp. 701-707 ◽  
Author(s):  
M. M. Doroodmand ◽  
S. Sobhani ◽  
A. Ashoori
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Chemical Vapor ◽  
Catalytic Amount ◽  
Multiwalled Carbon ◽  
One Pot ◽  
Heterogeneous Nanocatalyst ◽  
Aldehydes And Ketones ◽  
Simple Filtration

Sulfonated multiwalled carbon nanotubes (MWCNTs) were synthesized by chemical vapor deposition (CVD) as a new and facile one-pot method using acetylene (as the CNT precursor), thiophene (as the sulfur precursor), and ferrocene (for in situ liberation of metal nanoparticles as the CNT nanocatalyst). A low catalytic amount of the resulting sulfonated MWCNTs with a turnover number (TON) up to 980 and a turnover frequency (TOF) up to 11 160 h–1 was utilized as a new and recyclable heterogeneous nanocatalyst for the efficient one-pot synthesis of various amines (secondary and tertiary) by direct reductive amination of aldehydes and ketones using NaBH4. The catalyst was easily isolated from the reaction mixture by simple filtration and reused at least five times without significant degradation in activity.

Multiwalled Carbon Nanotubes by Chemical Vapor Deposition Using Multilayered Metal Catalysts

2002 ◽  
Vol 106 (22) ◽  
pp. 5629-5635 ◽  
Author(s):  
Lance Delzeit ◽  
Cattien V. Nguyen ◽  
Bin Chen ◽  
Ramsey Stevens ◽  
Alan Cassell ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Multiwalled Carbon Nanotubes ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Metal Catalysts ◽  
Multiwalled Carbon

Multiwalled Carbon Nanotubes Covered with Cobalt (II) Phthalocyanine by In Situ Synthesis and its Electrochemical Sensing Performance towards DA and UA

2014 ◽  
Vol 809-810 ◽  
pp. 43-52
Author(s):  
Hua Hua Wang ◽  
Nan Li ◽  
Kai Li ◽  
Yuan Bu ◽  
Wen Le Dai ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Simultaneous Detection ◽  
Thick Layer ◽  
Electrochemical Sensing ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Platinum Particles

Multiwalled carbon nanotubes (MWCNTs) as an excellent supporter covered with a thick layer of cobalt phthalocyanine (CoPc) were prepared by in-situ synthesis. Platinum particles were adopted to enhance the conductivity of CoPc-MWCNTs. The final nanocomposite Pt-CoPc-MWCNTs was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Strong aromatic π-π stacking between MWCNTs and CoPc made CoPc in-situ forming on MWCNTs. With homogeneous thickness of CoPc covered on the MWCNTs and Pt particles equally distributed, the nanocomposite was used as electrocatalyst. The electrochemical properties of the composite got researched by casting the dispersion of Pt-CoPc-MWCNTs on the glassy carbon electrode. Compared with other modified electrodes, Pt-CoPc-MWCNTs/GC electrode exhibited excellent electrochemical activity towards dopamine (DA) and uric acid (UA). Linear responses for DA and UA were obtained in the ranges of 5 to 170 μM and 5 to 100 μM, and limits of detection were 2.6 and 1.4 μM (S/N= 3), respectively. Simultaneous detection of DA and UA in the presence of ascorbic acid (AA) also displayed selective property, with no interference to each other.

In-Situ Characterization of Carbon Nanotube-Polystyrene Composite Deformation

2000 ◽  
Vol 6 (S2) ◽  
pp. 40-41
Author(s):  
D. Qian ◽  
E. C. Dickey ◽  
R. Andrews ◽  
T. Rantell ◽  
B. Safadi
Keyword(s):  
Carbon Nanotubes ◽  
Load Transfer ◽  
Electronic Materials ◽  
Composite Films ◽  
Chemical Vapor ◽  
Ex Situ ◽  
In Situ Tem ◽  
Multiwalled Carbon ◽  
Young’S Moduli

Carbon nanotubes (NTs) have novel electronic properties and exceptionally high Young's moduli on the order of TPa. so NTs have potential applications in advanced composite materials such as conductive polymers, electromagnetic-radio frequency interference (EMI/RFI) shielding material and opto-electronic materials. The utility of the nanotubes in composite applications depends strongly on the ability to disperse the NTs homogeneously throughout the matrix without destroying the integrity of the NTs. Furthermore, interfacial bonding between the NT and matrix is necessary to achieve load transfer across the interface, which is desirable for improving the mechanical properties of polymer composites.In this work, aligned multiwalled carbon nanotubes (MWNTs) produced by continuous chemical vapor deposition (CVD) (see Fig.l), were homogeneously dispersed in polystyrene (PS) matrices by a simple solution-evaporation method. Using this procedure, we made uniform MWNT-PS composite films ∼0.4mm thick for ex-situ mechanical tensile test and very thin films, ∼100nm, for in-situ TEM tests, as shown in Fig.2.

scholarly journals Miniemulsion copolymerization of (meth)acrylates in the presence of functionalized multiwalled carbon nanotubes for reinforced coating applications

2017 ◽  
Vol 8 ◽  
pp. 1328-1337 ◽  
Author(s):  
Bertha T Pérez-Martínez ◽  
Lorena Farías-Cepeda ◽  
Víctor M Ovando-Medina ◽  
José M Asua ◽  
Lucero Rosales-Marines ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Miniemulsion Polymerization ◽  
Polymer Chains ◽  
Multiwalled Carbon ◽  
Neat Polymer ◽  
In Situ Composites ◽  
3D Network ◽  
Insoluble Polymer

Film forming, stable hybrid latexes made of methyl metacrylate (MMA), butyl acrylate (BA) and 2-hydroxyethyl methacrylate (HEMA) copolymer reinforced with modified multiwalled carbon nanotubes (MWCNTs) were synthesized by in situ miniemulsion polymerization. The MWCNTs were pretreated by an air sonication process and stabilized by polyvinylpyrrolidone. The presence of the MWCNTs had no significant effect on the polymerization kinetics, but strongly affected the polymer characteristics (T g and insoluble polymer fraction). The performance of the in situ composites was compared with that of the neat polymer dispersion as well as with those of the polymer/MWCNT physical blends. The in situ composites showed the presence of an additional phase likely due to the strong interaction between the polymer and MWNCTs (including grafting) that reduced the mobility of the polymer chains. As a result, a substantial increase of both the storage and the loss moduli was achieved. At 60 °C, which is above the main transition region of the polymer, the in situ composites maintained the reinforcement, whereas the blends behaved as a liquid-like material. This suggests the formation of a 3D network, in good agreement with the high content of insoluble polymer in the in situ composites.

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