scholarly journals Esterification of levulinic acid via catalytic and photocatalytic processes using fluorinated titanium dioxide materials

2021 ◽  
Author(s):  
Claudia Patricia Castañeda Martínez ◽  
José Jobanny Martínez Zambrano ◽  
Andrés Camilo Mesa
Keyword(s):  
Titanium Dioxide ◽  
Levulinic Acid ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Fluoride Anion ◽  
Esterification Reaction ◽  
X Ray Diffraction ◽  
Catalytic Activation ◽  
Photocatalytic Processes

This study evaluated the synthesis, characterization, and activity of fluorinated titanium dioxide materials (TiO2-F 1% and TiO2-F 5%) in-situ modified by the sol-gel method in the esterification reaction of levulinic acid conducted by catalytic and photocatalytic processes. The physicochemical properties of the materials were determined by X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, thermal analysis, and pyridine adsorption. It was found that the inclusion of fluoride anion causes a decrease in the levulinic acid conversion by photocatalytic reaction; however, in the catalytic activation, a slight increase in the conversion using the fluoride materials was observed. Finally, the reaction in the presence of halogenated solvents (CCl4) by photolysis reaction favors a conversion of 100% in 1h.

Synthesis, Characterization and Properties of PANI/(La-Nd Doped BaFe12O19) Composites

2017 ◽  
Vol 727 ◽  
pp. 327-334
Author(s):  
Yan Wang ◽  
Jun Wang ◽  
Xiao Fei Zhang ◽  
Ya Qing Liu
Keyword(s):  
Sol Gel ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Structure Morphology ◽  
Xrd Patterns ◽  
Hexagonal Platelet ◽  
Peak Value ◽  
Properties Of Composites

La-Nd co-doped barium hexaferrites, Ba0.7(LamNdn)0.3Fe12O19 (D-BaM), were successfully prepared by sol-gel method. PANI / D-BaM composites were synthesized by in-situ polymerization in solution. The structure, morphology and properties of samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), four-probe conductivity tester and vector network analyzer. The XRD patterns showed that the crystal structure of all the samples exist as M-type phases. The SEM images revealed that the particles presented a hexagonal platelet-like morphology. The magnetic properties could be improved by substitutions of La and Nd ions. The saturation magnetization (Ms) and coercive force (Hc) increased with the change of La / Nd ratio to the maximum at La / Nd = 3:1. The doped particles have also been embedded in conductive PANI to prepare electromagnetic materials, and the conductivity kept on the order of 10-2. The microwave absorbing properties of composites at 30 MHz-6 GHz improved obviously, the peak value of reflection loss could reach-7.5 dB.

Visible-Light-Induced Photocatalytic Activity of Boron-Doped BiVO4

2014 ◽  
Vol 809-810 ◽  
pp. 890-894
Author(s):  
Dan Li ◽  
Lian Wei Shan ◽  
Gui Lin Wang ◽  
Li Min Dong ◽  
Wei Li ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Reflectance Spectroscopy ◽  
Scheelite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Boron Doped

Boron-BiVO4 samples were synthesized by sol-gel method. They were characterized by UV-vis diffuse reflectance spectroscopy, X-ray diffraction. Photocatalytic activity of the obtained BiVO4 samples was investigated through degrading methylene blue (MB). The results reveal that boron-BiVO4 catalysts have monoclinic scheelite structure. The BiVO4 and Co-BiVO4 photocatalysts were responsive to visible light. Co-BiVO4 photocatalyst showed higher photocatalytic activity than pure BiVO4, resulting in the significantly improved efficiency of degradation of MB.

Titanium Dioxide-Supported Sulfonated Low Rank Coal as Catalysts in the Oxidation of Styrene with Aqueous Hydrogen Peroxide

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Mukhamad Nurhadi ◽  
Jon Efendi ◽  
Lee Siew Ling ◽  
Teuku Meurah Indra Mahlia ◽  
Ho Chin Siong ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Rank ◽  
Bet Surface Area ◽  
High Catalytic Activity ◽  
Low Rank Coal ◽  
X Ray Diffraction ◽  
Aqueous Hydrogen Peroxide

Titanium dioxide supported sulfonated low rank coal catalyst possesses high catalytic activity in liquid phase oxidation of styrene with aqueous hydrogen peroxide at room temperature. The catalysts were prepared by sulfonation with concentrated sulfuric acid and impregnation of titanium dioxide (500-2500 µmol). The effect of titanium dioxide impregnation and calcinations on the catalysts were studied by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, BET surface area, field emission scanning electron microscopy and hydrophobicity measurement. The catalytic activity of the catalysts in the oxidation of styrene by aqueous H2O2 without calcination increased when the amount of titanium dioxide increased. Meanwhile, the catalytic activity of the catalyst calcined at 500oC for 2 h was lower than before calcination. It is suggested that the agglomeration of titanium dioxide and hydrophobicity play important role in the catalytic activity of titanium dioxide-supported sulfonated low rank coal in the oxidation of styrene with aqueous H2O2. 

scholarly journals Synthesis of Zinc Oxide Supported on Titanium Dioxide for Photocatalytic Oxidative Desulfurization of Dibenzothiophene

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Hitam, C.N.C. ◽  
Jalil, A.A. ◽  
Triwahyono, S.
Keyword(s):  
Zinc Oxide ◽  
Titanium Dioxide ◽  
High Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Oxidative Desulfurization ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Desulfurization Rate ◽  
Low Energy Consumption

Photocatalytic oxidative desulfurization (PODS) has received much attention due to low energy consumption and high efficiency, as well as simple and pollution-free operation. In this study, zinc oxide supported on titanium dioxide (ZnO/TiO2) catalysts were prepared via a simple electrochemical method. The presence of anatase phase TiO2 and wurtzite ZnO was confirmed by X-ray diffraction (XRD) analysis while band gap energies were determined by UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic activity was tested for desulfurization of 100 mg/L dibenzothiophene (DBT). The highest desulfurization rate (2.20 × 10-3 mM/min) was achieved using 1 g/L of 10 wt% ZnO/TiO2 after 2 hr under UV irradiation.

Doping Titanium Dioxide by Fluoride Ion

2019 ◽  
Vol 946 ◽  
pp. 181-185 ◽  
Author(s):  
Sergei N. Fedorov ◽  
Vladimir Yuryevich Bazhin ◽  
Vladimir G. Povarov
Keyword(s):  
Titanium Dioxide ◽  
Hydrofluoric Acid ◽  
Thermodynamic Data ◽  
Temperature Increase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Fluoride Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Doped Titanium Dioxide

Titanium dioxide has a special feature: anatase, to rutile transformation which was considered in our investigations. It is especially important to keep anatase form of titanium dioxide for photocatalytic materials, different ceramics with tribo-chemical properties, self-cleaning coatings and self-sterilizing coatings. For that only one of the titanium dioxide forms is more suitable – anatase, which is more active but not stable, because it transforms to rutile during the time or with the temperature increase loses its activity. Different methods of stabilising anatase have been considered in the paper. Several doping agents have been determined and it was chosen fluorine ion to modify titanium dioxide. Stabilization of anatase is achieved by preparing the reaction mixture by a sol-gel method with hydrofluoric acid. It has shown thermodynamic data, results of experiment, temperatures of anatase to rutile transformation of non-doped and doped titanium dioxide, its X-Ray diffraction and TGA. It is proved that titanium dioxide doped by fluorine ion keeps anatase form till the temperature is more than 1000 °C.

Effects of Glass Elements on the Structural Evolution ofin situGrown Ferroelectric Perovskite Crystals in Sol-gel Derived Glass-ceramics

1997 ◽  
Vol 12 (4) ◽  
pp. 1131-1140 ◽  
Author(s):  
Kui Yao ◽  
Weiguang Zhu ◽  
Liangying Zhang ◽  
Xi Yao
Keyword(s):  
Crystallization Process ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Structural Evolution ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Process Change ◽  
X Ray ◽  
Ferroelectric Perovskite

Several ABO3perovskite ferroelectric crystals, PbTiO3, Pb(Zr, Ti)O3, and BaTiO3have beenin situgrown from amorphous gels with glass elements, and the structural evolution has been systematically investigated using x-ray diffraction (XRD), infrared spectra (IR), differential thermal analysis (DTA), thermogravimetric analysis (TGA), and dielectric measurements. It is found that in the Si-contained glass-ceramic systems, Si and B glass elements are incorporated into the crystalline structures, resulting in the variation of the crystallization process, change of lattice constant, and dielectric properties. Some metastable phases expressed by a general formula AxByGzOw(A = Pb and Ba; B = Zr and Ti; G for glass elements, especially for Si) have been observed and discussed.

Sol–gel preparation of V2O5 sheets and their lithium storage behaviors studied by electrochemical and in-situ X-ray diffraction techniques

2014 ◽  
Vol 40 (4) ◽  
pp. 6115-6125 ◽  
Author(s):  
Lianyi Shao ◽  
Kaiqiang Wu ◽  
Xiaoting Lin ◽  
Miao Shui ◽  
Rui Ma ◽  
...  
Keyword(s):  
Sol Gel ◽  
X Ray Diffraction ◽  
Lithium Storage ◽  
X Ray ◽  
Gel Preparation

OPTIMIZATION STUDIES OF OIL PALM EMPTY FRUIT BUNCH LIQUEFACTION FOR CARBON CRYOGEL PRODUCTION AS CATALYST IN LEVULINIC ACID ESTERIFICATION

2018 ◽  
Vol 80 (2) ◽  
Author(s):  
Muzakkir Mohammad Zainol ◽  
Nor Aishah Saidina Amin ◽  
Mohd Asmadi
Keyword(s):  
Oil Palm ◽  
Levulinic Acid ◽  
Condensation Reaction ◽  
Sol Gel ◽  
Esterification Reaction ◽  
Empty Fruit Bunch ◽  
Carbon Cryogel ◽  
Predicted Values ◽  
Poly Condensation ◽  
Acid Esterification

Liquefaction of oil palm empty fruit bunch (EFB) using 1-butyl-3-methylimidazolium chloride was investigated in this study. The experiments were designed based on central composite by response surface methodology (RSM). The optimum conditions for the predicted liquefied EFB yield of 80.97 wt% was obtained at the temperature of 151.9 °C, a reaction time of 112.78 min and a ratio (Ionic liquid to EFB) of 4.27. The Regression coefficient (R2) for the model was 0.90 indicating a high correlation between observed and predicted values. The liquefied EFB mixture was used in the preparation of carbon cryogel via a sol-gel poly-condensation reaction and calcination process. The presence of sulfuric acid during the gel synthesis promoted an active site on the gel linkage and surface. The carbon cryogel prepared was tested as catalyst in an esterification reaction. The conversion of levulinic acid and yield of ethyl levulinate were reported as 58.7% ansd 57.2 mol%, respectively.

Synthesis of Ultra-Thin Superhydrophilic Titanium Oxide Film and its Effects on the Capillary of Microchannels

2010 ◽  
Author(s):  
Min Zhang ◽  
Bo Zhang ◽  
Tianhong Cui
Keyword(s):  
Titanium Oxide ◽  
Sol Gel ◽  
Nitrogen Atmosphere ◽  
Tio2 Films ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Before And After ◽  
Potential Applications ◽  
Temperature Surface

Ultra-thin superhydrophilic titanium oxide films were fabricated on silicon microchannels by an in situ reaction sol-gel method using titanium tetraisopropoxide as a starting material.. By changing the concentration of water in ethanol and reaction time, the thickness of synthesized TiO2 films can be controlled from around 10 nm to 80 nm. The contact angle of as-synthesized TiO2 films on flat silicon is around 20° and can be further decreased to zero by calcination at 700 °C in nitrogen atmosphere. X-ray diffraction spectra show the microstructure of the TiO2 films changed gradually from amorphous to anatase with the increase of calcination temperature. Surface morphology of the film before and after calcination also shows that a smoother coating with crystal structure was obtained by heat treatment. The flow velocity in the TiO2 coated channel reached around 0.03 m/s, almost ten times of that in PDDA/PSS coated channel and 4 times of that in SiO2 coated one. The ultra-thin superhydrophilic TiO2 films fabricated by this method show the ability to strongly increase the wettability of microchannels without affecting the morphology of the sidewall of the channels, indicating potential applications to biomolecule analysis and surface tension driven microfluidic systems.

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