Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Publisher: search.filters.publisher.01. Izmir Institute of TechnologySubject: search.filters.subject.Catalysts

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Now showing 1 - 4 of 4
  • Master Thesis
    Esterification of oleic acid with methanol on structured solid acid catalysis
    (01. Izmir Institute of Technology, 2024) Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Bu çalışmada, Oleik Asit metanol ile birlikte Sülfonlanmış Alüminyum Silika (SAS) heterojen asidik katalizörü üzerinde gerçekleştireceği esterifikasyon reaksiyonu incelenecektir. Araştırma, farklı metanol/yağ asidi mol oranları (9/1-21/1), katalizör miktarları (%10-%20) ve reaksiyon sürelerinin (3s–9s) 105°C sıcaklıkta reaksiyon verimliliği üzerindeki etkisini Box Bhenkhen yardımı ile değerlendirmeyi amaçlamaktadır. Katalizörlerin aktivitesi iki farklı katalizör formu (toz, yapısal) ele alınarak değerlendirilecektir. Bu çalışma, varyans analizi istatistiksel sonuçlarına göre, toz katalizör varlığında gerçekleştirilen deneylerde reaksiyon süresinin dönüşüm değerleri üzerinde en büyük etkiye sahip olduğunu göstermektedir. Reaksiyon süresi uzadıkça dönüşüm oranları hızlı bir şekilde artmıştır. Ayrıca, kullanılan katalizör miktarı da doğrudan etkili olmuş ve en yüksek dönüşüm oranı, Alkol/FFA oranının 9/1 olduğu durumda elde edilmiştir. Ayrıca, yapısal katalizörlerin varlığında gerçekleşen reaksiyonun dönüşüm değerinin, toz formundaki katalizörlerin değerleriyle karşılaştırılabilir olduğu tespit edilmiştir. Ayrıca yapılandırılmış katalizörlerde toz katalizöre göre ayırma adımına gerek kalmamıştır.
  • Master Thesis
    Biolubricant Production Over Sulfated Ti-Sba and Tio2-Sio2 Based Mesoporous Catalysts
    (01. Izmir Institute of Technology, 2022) Özperçin, Tuğçe; Özperçin, Tuğçe; Yılmaz, Selahattin; Yılmaz, Selahattin; 01. Izmir Institute of Technology; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering
    Production of ecofriendly biodegradable lubricants from vegetable oils is an attractive alternative to petroleum derived lubricants for environmental protection. This study presents an investigation for the production of biolubricants via ring opening reaction of epoxidized soybean oil using the mesoporous solid acid catalysts. SO4/SBA- 15, SO4/Ti-SBA-15, SO4/TiO2-SiO2 and SO4/La-TiO2-SiO2 catalysts were prepared and characterized. In addition, effect of increasing titanium content on SO4/Ti-SBA-15 (Si/Ti: 10, Si/Ti: 6) and effect of sulfation source (ammonium sulfate and chlorosulfonic acid) on Ti-SBA-15 and La-TiO2-SiO2 properties, activities and stabilities were studied. Activity and stability of all the catalysts were tested in the ring opening reactions of epoxidized soybean oil with 2-propanol at 80 oC with 10/1 alcohol-epoxide mol ratio. After determination of the two most stable and active catalysts, reactions were also performed with 2-ethylhexanol at 100 oC with 6/1 alcohol-epoxide mol ratio. Products were analyzed by titration, FTIR and H-NMR. Also, thermal stability and low temperature behavior of products were determined by thermogravimetric analysis and differential scanning calorimetry. Prepared catalsysts had mesoporous structure and stronger acid sites by attachment of sulfate groups The catalysts showed a serious leaching when they were sulfated with ammonium sulfate. On the other hand, chlorosulfonic acid treatment enhanced significantly stability of catalyst. Furthermore, increasing of titanium content and sulfation with chlorosulfonic acid increased the acidity of catalysts compared to ammonium sulfate. The SO4/Ti-SBA-15-6(CS) catalyst (Si/Ti:6 mole ratios and chlorosulfonic acid sulfated) was found as the most stable and active catalyst. It provided 62 % (12 h) and 90 % (18 h) conversion in the reactions with 2-propanol and 2-ethylhexanol, respectively. All products were found as thermally stable up to 300 oC showing that ring opening reaction did not affect thermal stability. Nevertheless, it affected positively low temperature properties and better low temperature properties were obtained from the products of reactions with 2-ethylhexanol. However, its influence on the products obtained from 2-propanol was not prominent.
  • Master Thesis
    Butyl Esters Production From Canola Oil Over Heterogeneous Base Catalysts
    (01. Izmir Institute of Technology, 2021) Akın, Oğuzhan; Şeker, Erol; Şeker, Erol; Şeker, Erol; 01. Izmir Institute of Technology; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering
    In this study, transesterification reaction of canola oil with butanol over calcium oxide alumina catalyst was investigated with varying butanol:lipid molar ratios, catalyst amount and reaction time. Catalysts were prepared with the single step sol-gel method, and the activity of synthesized catalysts were investigated for two different forms of catalysts as powder and structured form. In the case of powdered catalysts, at butanol:lipid molar ratios of 9 and 24 with 6 wt% of lipids as catalyst amount, leaded 32% and 45% butyl esters yield in 1 hour. On the other hand, ~70% butyl esters yield has obtained at butanol:lipid molar ratios of 48 and 60 for the reaction time of 1 hour, while 89% yield had achieved when the reaction lasted for 4 hours at butanol:lipid molar ratio of 48. The necessity of mild basic strength and high butanol:lipid molar ratio was found to obtain high butyl esters yield. At high butanol lipid ratios of 48 and 60, it was observed that glycerolysis reaction occurs and promotes reverse transesterification reactions in first 30 minutes of the experiments. In the case of structured catalysts, lower butyl esters yields than powder catalysts were obtained, yet they eliminated the need for catalysts separation step in the experiments. Reusability tests showed that catalyst activity has decreased due to calcium ion leaching in the first hour of reaction and kept its activity constant for the rest of the reaction.
  • Master Thesis
    A Comparative Study on the Photocatalytic Activity of Dye-Sensitized and Non-Sensitized Graphene Oxide-Ti̇o2 Composites Under Simulated and Direct Sunlight
    (01. Izmir Institute of Technology, 2019) İlhan, Hatice; Varlıklı, Canan; Demir, Mustafa Muammer; Varlıklı, Canan; Demir, Mustafa Muammer; 04.04. Department of Photonics; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    Amine modified graphene oxide (mGO) and TiO2 composite was synthesized by low temperature hydrothermal method. Characterization of the synthesized material was carried out by using X-ray diffraction, X-ray photoelectron spectroscopy, and BET analysis techniques. The films of mGO:TiO2 and formerly synthesized TiO2, N-TiO2, GO-TiO2 and GO:N-TiO2 were fabricated by doctor blade method and employed as photocatalysts for the photodegradation of Rhodamine-B (RhB) dye under simulated (Xe lamb) and direct sun-light. P25 was also used as reference photocatalyst for all of the synthesized ones. Photodegradation of RhB was monitored by UV-Vis spectroscopy. Among all the catalysts, GO:N-TiO2, the composite of GO and N-doped TiO2, presented the best photocatalytic activity and although the activity of mGO:TiO2 was better than the activities of P25 and TiO2, it presented lower degradation rate constant even than that of the N-TiO2. It is proposed that increased abundance of C-C bonds and decreased number of oxygenated functional groups on mGO:TiO2, in addition to the morphological difference between GO (sheet like) and mGO (dot like) has great influence on their photocatalytic activities. Among the GO containing photocatalysts including mGO:TiO2, specific surface area (SSA) and number of RhB molecules per film volume were the lowest and particle size was the highest for mGO:TiO2. Although the number of RhB molecules per film volume was higher in mGO:TiO2 than that of the N-TiO2, it is thought that approximately 2 folds higher SSA of N-TiO2 allowed better photocatalytic performance. Additionally, the films were sensitized with PTE dye to obtain effective catalysts in visible region and reusability of the films were also tested. Degradation rate constants of all fabricated films have increased under both of the irradiation media and no significant change in rate constants were detected after the reusability tests.