Polyoxometalate and copolymer-functionalized ionic liquid catalyst for esterification

2011 ◽  
Vol 84 (3) ◽  
pp. 541-551 ◽  
Author(s):  
Huan Li ◽  
Jizhong Chen ◽  
Li Hua ◽  
Yunxiang Qiao ◽  
Yinyin Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ionic Liquid ◽  
Fourier Transform ◽  
Room Temperature ◽  
Homogeneous Solution ◽  
Imidazolium Cation ◽  
Transmission Electron ◽  
Ft Ir ◽  
Halogen Free

A new room-temperature ionic liquid (RTIL) consisting of a polyoxometalate (POM) anion and tri-block copolymer (P123)-functionalized imidazolium cation was synthesized and utilized as a halogen-free catalyst for esterification. The catalytic system was a homogeneous solution at the beginning of the reaction, but an emulsion formed during the course of the reaction, and a progressive phase separation of the catalyst occurred at 0 °C over the course of 3 h. Dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier transform/infrared spectroscopy (FT/IR) have been used to characterize the properties of the IL during the reaction. The new IL catalyst was found to be highly efficient in the esterification of various alcohols and can be recycled at least seven times.

Novel Methods for Preparation and Surface Treatment of Nano-CaCO3

2013 ◽  
Vol 750-752 ◽  
pp. 336-339
Author(s):  
Fa Chao Wu ◽  
Teng Fei Shen
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Fourier Transform ◽  
Room Temperature ◽  
Transmission Electron ◽  
Reduce Energy Consumption ◽  
Scanning Electron

In this work, CaCO3 nanoparticles have been synthesized via heat-treatment of a new precursor. Effect of calcinations temperature on particle size has been investigated. The products were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). nanoCaCO3 was modified using chloroform as solvent and fatty acid as modifier atroom temperature. The advantage of this modification is that it can be proceed at room temperature and it can reduce energy consumption.

Synthesis of Fe 3+-Dopped PANI Conductive Nanomaterials via Interfacial Polymerization

2011 ◽  
Vol 239-242 ◽  
pp. 2839-2842
Author(s):  
Hong Mei Mu ◽  
Peng Fei ◽  
Bi Tao Su ◽  
Zi Qiang Lei
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Ir Spectroscopy ◽  
Interfacial Polymerization ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Conductive Nanomaterials ◽  
Ft Ir Spectroscopy

A series of Fe3+-dopped polyaniline (Fe3+/PANI) nanomaterials with different morphologies and a higher conductivity were successfully synthesized using a simple and static interfacial polymerization by using FeCl3 as both oxidant catalyst and dopant. The effect of surfactants CTAB and SDS and the concentration of FeCl3 on the morphology and conductivity of Fe3+/PANI nanomaterial were investigated. The samples were characterized by Transmission Electron Microscopy (TEM), SDY-4 probes conductivity meter, X-ray Diffractometry (XRD), Energy dispersive spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy techniques. TEM’s results showed that their morphologies changed with the type of the surfactant and the concentration of FeCl3. Introducing surfactants CTAB and SDS into Fe3+/PANI remarkably improved the conductivity of the material. The conductivities of CTAB/Fe3+/PANI and SDS /Fe3+/PANI nanomaterials were respectively about 4.8×10-2 and 1.3×10-2 S/cm while the conductivity of Fe3+/PANI was found to be 1.5×10-4 S/cm. The different morphology and high conductivity may be ascribed to the mutual effects of the surfactant and oxidant.

scholarly journals Changes in Ultrastructure and Fourier Transform Infrared Spectrum of Salmonella enterica Serovar Typhimurium Cells after Exposure to Stress Conditions

2010 ◽  
Vol 76 (22) ◽  
pp. 7598-7607 ◽  
Author(s):  
A. Alvarez-Ordóñez ◽  
M. Prieto
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Stress Response ◽  
Salmonella Enterica ◽  
Fourier Transform Infrared ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
Serovar Typhimurium ◽  
Ft Ir

ABSTRACT The effect of exposure to acid (pH 2.5), alkaline (pH 11.0), heat (55°C), and oxidative (40 mM H2O2) lethal conditions on the ultrastructure and global chemical composition of Salmonella enterica serovar Typhimurium CECT 443 cells was studied using transmission electron microscopy and Fourier transform infrared spectroscopy (FT-IR) combined with multivariate statistical methods (hierarchical cluster analysis and factor analysis). Infrared spectra exhibited marked differences in the five spectral regions for all conditions tested compared to those of nontreated control cells, which suggests the existence of a complex bacterial stress response in which modifications in a wide variety of cellular compounds are involved. The visible spectral changes observed in all of the spectral regions, together with ultrastructural changes observed by transmission electron microscopy and data obtained from membrane integrity tests, indicate the existence of membrane damage or alterations in membrane composition after heat, acid, alkaline, and oxidative treatments. Results obtained in this study indicate the potential of FT-IR spectroscopy to discriminate between intact and injured bacterial cells and between treatment technologies, and they show the adequacy of this technique to study the molecular aspects of bacterial stress response.

A Facile Approach to Synthesis and Modification of Nano-Alumina

2013 ◽  
Vol 774-776 ◽  
pp. 646-649
Author(s):  
Teng Fei Shen ◽  
Ying Juan Sun
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Fourier Transform ◽  
Room Temperature ◽  
Transmission Electron ◽  
Nano Alumina ◽  
Reduce Energy Consumption ◽  
Scanning Electron

In this work, nanoAlumina particles (nanoAl2O3) have been synthesized via solid state reaction. Effect of quantity of surfactant on particle size has been investigated. nanoAl2O3 was modified using chloroform as solvent and fatty acid as modifier at room temperature. The advantage of this modification is that it can be proceed at room temperature and it can reduce energy consumption. The products were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Organophilic Modification and Application of Nano-Fumed Silica in Pervaporation of Ethanol / Water Mixture

2011 ◽  
Vol 117-119 ◽  
pp. 679-682
Author(s):  
Bing Bing Li ◽  
Liang Wang ◽  
De Sun
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Fumed Silica ◽  
Water Mixture ◽  
Transmission Electron ◽  
Ft Ir ◽  
Scanning Electron ◽  
Better Than

Fumed Silica was modified with hexamethyldisiazane (HMDZ, modifier) and dimethyldiethoxysilane (DMDEOS, co-modifier) by grafting method. The structure of organo-functionnalized nanoparticles was characterized by fourier transform infrared spectrum (FT-IR) and transmission electron microscopy (TEM). Functional nanosilica-filled polydimethylsiloxane(PDMS) composites membrane were prepared. Scanning electron microscopy (SEM) observations of composites revealed good dispersion of the silica nanoparticles and the pervaporation performance of the filled PDMS membranes is better than that of the unfilled PDMS membranes.

scholarly journals Deformation-induced nanocrystallization: A comparison of two amorphous Al-based alloys

2005 ◽  
Vol 20 (3) ◽  
pp. 696-702 ◽  
Author(s):  
W.H. Jiang ◽  
F.E. Pinkerton ◽  
M. Atzmon
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
High Resolution ◽  
Room Temperature ◽  
Shear Bands ◽  
Low Density ◽  
Boundary Zone ◽  
Kinetic Effect ◽  
Transmission Electron

Using conventional and high-resolution transmission electron microscopy (HRTEM), the effects of rolling at room temperature on the microstructures of amorphous Al90Fe5Gd5 and Al86.8Ni3.7Y9.5 were compared. In rolled Al90Fe5Gd5, nanocrystallites were observed at shear bands, whereas none were observed in rolled Al86.8Ni3.7Y9.5. When HRTEM was combined with with Fourier transform filtering, nanoscale, low-density defects were imaged. In Al90Fe5Gd5, the shear bands contain few defects, which are concentrated at the boundary zone between the shear bands and undeformed region, whereas in Al86.8Ni3.7Y9.5, the shear bands contain a uniform distribution of defects with a density higher than the undeformed region. The preferential precipitation of nanocrystallites in rolled Al90Fe5Gd5 is attributed to a kinetic effect due to uniformly-distributed excess free volume in the shear bands.

scholarly journals Synthesis of Platinum Nanoparticles by Gamma Co-60 Ray Irradiation Method Using Chitosan as Stabilizer

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Thi Kim Lan Nguyen ◽  
Ngoc Duy Nguyen ◽  
Van Phu Dang ◽  
Dinh Tuan Phan ◽  
Thai Hoa Tran ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Platinum Nanoparticles ◽  
Gamma Ray ◽  
Visible Spectroscopy ◽  
Chitosan Concentration ◽  
Transmission Electron ◽  
Gamma Ray Irradiation ◽  
Ft Ir

Platinum nanoparticles were synthesized using the gamma-ray irradiation as a reducing factor and chitosan as a stabilizer. The prepared platinum nanoparticles were characterized using ultraviolet-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The saturated conversion dose to reduce the Pt4+ to Pt0 was found to be about 14 kGy for initial Pt4+ concentration of 1 mM. The size of the platinum nanoparticles (1.4–1.6 nm) did almost not change with the increase of chitosan concentration from 0.5 to 2.0%. Thus, gamma Co-60 ray irradiation method is favorable for synthesizing PtNPs with the small sizes.

scholarly journals The Effect of Multidentate Biopolymer Based on Polyacrylamide Grafted onto Kappa-Carrageenan on the Spectrofluorometric Properties of Water-Soluble CdS Quantum Dots

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Ghasem Rezanejade Bardajee ◽  
Zari Hooshyar ◽  
Yousof Pourhasan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Fourier Transform ◽  
Graft Copolymerization ◽  
Water Soluble ◽  
Cds Quantum Dots ◽  
Transmission Electron ◽  
Ft Ir ◽  
Kappa Carrageenan

A new fluorescent composite based on CdS quantum dots immobilized on the multidentate biopolymer matrix is prepared through the graft copolymerization of the acrylamide onto kappa-Carrageenan. A variety of techniques like thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) was used to confirm the structure of the obtained samples. To investigate the spectrofluorometric properties, fluorescence spectroscopy of the obtained quantum dots was studied.

scholarly journals Fast Microwave-Assisted Synthesis and Photoluminescence of CaWO4Nanocrystals

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Quanguo Li ◽  
Yanhua Shen ◽  
Taohai Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Microwave Assisted Synthesis ◽  
X Ray ◽  
Microwave Assisted ◽  
Transmission Electron ◽  
Ft Ir ◽  
Microwave Assisted Method

In this work, CaWO4nanoparticles have been synthesized by microwave-assisted method at a low temperature of 120°C. The as-prepared powders were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). It is found that the reaction time played an important role in the morphology controlling and crystallinity level of CaWO4crystals. The effects of photoluminescent properties have a great relationship with crystallinity.

scholarly journals PERFORMANCE OF TiO2 IN PHOTODEGRADATION SEAFOOD WASTEWATER

2018 ◽  
Vol 54 (4B) ◽  
pp. 80
Author(s):  
Luu Cam Loc
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Bet Surface Area ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Scanning Electron

In this work, photocatalysts TiO2-HT prepared by hydrothermal method and TiO2-P25 Degussa were characterized by Energy Dispersive X-Ray analysis (EDX), X-ray powder diffraction analysis (XRD), Raman Spectroscopy, BET surface area measurements, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and UV-Vis absorption spectroscopy and tested in degradation of recalcitrant organic pollutants in bio-treated seafood wastewater (COD > 80 mg/L). After 9 hours of photodegradation under UV-A irradiation, COD removal efficiency reached 85.6 % and 48.9 % on TiO2-P25 and TiO2 catalysts, respectively. COD values of seafood wastewater treated by photocatalysis met the standard discharge requirement - QCVN 11:2008 – level A (COD £ 50 mg/L). 

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