Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Production of Butyl Glucosides by Zr-Sba & So4/Zr-sba-15 Catalysts(Izmir Institute of Technology, 2020) Yılmaz, Selahattin; Yılmaz, Selahattin; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe purpose of this study was to develop mesoporous solid acid catalyst for glycosidation reaction of butanol. Therefore, Zr incorporated SBA-15 silica materials with two different amount of zirconia loadings were prepared by hydrothermal synthesis. In addition to them, sulfate modified forms (SO/Zr-SBA-15) were prepared by treating Zr-SBA-15 catalysts in 0.5 M and 1.0 M H2SO4 solutions respectively. These 6 catalysts were tested in the glycosidation of butanol and as product butyl glucosides were produced. The reaction tests were carried out in a 100 ml glass reactor at 117°C. Catalysts properties were determined by different characterization techniques. The analysis showed that mesoporous, acidic catalysts were obtained and zirconium was incorporated into SBA-15 structure. While the surface area and pore diameter decreased by higher zirconium loading and sulfonation, acidity of the catalysts increased. The highest acidity was observed in 1.0 SO/Zr-SBA-15-(1.0) catalyst. The formation of butyl glucosides was determined by HPLC analysis. Results showed that activity of the catalysts were different for the glycosidation reaction of butanol. The highest butyl glucoside yield was obtained with 1.0 SO/Zr-SBA-15-(1.0) catalyst, while the lowest yield was obtained with Zr-SBA-15-(1.0) catalyst. This was attributed to the higher acidity (2.35 mmol NH3/g cat.) and B/L ratio (1.97) of 1.0 SO/Zr-SBA-15-(1.0) catalyst with respect to the others. The reusability tests were performed up to 2 times for the catalyst with the best results. There was no major decrease (7%) in the product yields and this confirmed the stability and reusability of the catalysts.Master Thesis Development of Tungsten Loaded and Zirconia Incorporated Mesoporous Catalysts for Esterification of Palmitic Acid With Cetyl Alcohol(Izmir Institute of Technology, 2014) Mutlu, Vahide Nuran; Yılmaz, Selahattin; Yilmaz, Selahattin; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, it was pursued to develop acidic mesoporous catalysts for esterification of cetyl alcohol by palmitic acid. For this, Zr incorporated SBA-15 was prepared by hydrothermal synthesis. Zr-SBA-15 was used both as a catalyst support and as a catalyst itself. WO3 loading onto the Zr-SBA-15 was performed by incipient wetness impregnation. Additionally, WO3-ZrO2 catalyst was prepared by co-precipitation with two different contents of WO3 (15 wt% and 20 wt%). The reaction tests were carried out in mesitylene under reflux conditions. Zr was incorporated into SBA-15 successfully. The surface areas of Zr-SBA-15 and WO3/Zr-SBA-15 catalysts were significantly higher than that of WO3-ZrO2. Loading of WO3 decreased the surface area of Zr-SBA-15. The acidity of the WO3/Zr-SBA-15 with 15 wt% WO3 was higher than that of with 20 wt% WO3. Moreover, increasing the calcination temperature from 700 to 800 oC resulted in the increase of acidity. The activity of the catalysts differed. The only product obtained was cetyl palmitate. Under the test conditions it was found that the reaction rate was not limited by equilibrium. Zr-SBA-15 provided the highest conversion (64 %) which corresponded to cetyl palmitate yield of 63% among other mesoporous catalysts because of its high surface area (600.3 m2/g) and acidity (0.152 mmol NH3/g cat). This catalyst did not show leaching. WO3/Zr-SBA-15 based catalys tests showed that catalyst activity increased by increasing calcination temperature. This was atributed to better dispersion of W. The conversion of cetyl alcohol did not change much with more W loading.