Solvent free oxidation of benzyl alcohol to produce benzaldehyde using bimetallic Au-Pd supported catalysts
The study of using a gold and palladium as heterogeneous catalyst is commonly investigated for many oxidation process now days especially in benzyl alcohol oxidation. In this respect, the main goal of this research is to study the influence of oxidant with Au-Pd bimetallic catalyst to achieve hig...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/76805/1/FS%202018%2073%20-%20IR.pdf |
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| Summary: | The study of using a gold and palladium as heterogeneous catalyst is commonly
investigated for many oxidation process now days especially in benzyl alcohol
oxidation. In this respect, the main goal of this research is to study the influence of
oxidant with Au-Pd bimetallic catalyst to achieve highest potential to obtain more
benzaldehyde. The monometallic and bimetallic catalysts are synthesized via
impregnation and sol-immobilization methods. The structural, texturalphysicochemical,
morphological, and thermal characteristics of the synthesized catalysts hav
investigated by using X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA),
Transmission Electron Microscope (TEM) , High Resolution Transmission Electron
Microscopy (HRTEM) , Brunauer-Emmett-Teller (BET), Field Emission Scanning
Electron Microscopy (FESEM) and Temperature Programmed Desorption (TPDNH3).
On the other hand, an examination of the reusability and leaching of gold and
palladium into benzyl alcohol also was carried out. As a result, sol-immobilization
methods was shown produced stable catalysts, highly active density of both metal
loading, highest strength, large surface area and more selective for the oxidation
benzyl alcohol. The result also revealed that 1wt%Au-Pd/C catalyst prepared by solimmobilizations
methods showed the best catalytic activity in the oxidation of benzyl
alcohol at temperature of 80 ̊C for 4hours. Comparing with mono Au or Pd catalyst,
bimetallic Au-Pd gave alloy formation that contribute a synergy effects and showed
an improvement for conversion and selectivity on the benzyl alcohol oxidation. In
addition, the effect of variable parameters, such as reaction temperature, effect of
different support , heat treatment conditions, oxidant ratio, reaction time and metal
loading ratio have been evaluated for optimization to produce more benzaldehyde. It
was found that the activity and selectivity of the oxidation benzyl alcohol was highly
dependent on these variables. A good reusability of the catalysts with less of leaching
gold into the product has obtained also. As a conclusion, the oxidation of benzyl alcohol was successfully studied and the best
catalyst was Au-Pd/C that synthesized by using sol-immobilization. This catalyst was
found had a good distribution of narrowed small particles (2.79nm). Furthermore, the
importance of the H2O2 as an oxidant have been proven in this research. |
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