Vanadium and molybdenum incorporated mcm-41 catalysts for selective oxidation of ethanol

Güçbilmez, Yeşim
In this study, V-MCM-41, MCM-41 and Mo-MCM-41 catalysts were synthesized by the one-pot alkaline and acidic synthesis methods. The as-synthesized catalysts were found to have high BET surface areas (430-1450 m2/g), homogeneous pore size distributions (2-4 nm), good crystalline patterns and high metal loading levels (Metal/Si atomic ratio in the solid = 0.01-0.16) as determined by the characterization studies. MCM-41 and Mo-MCM-41 catalysts were highly active in the selective oxidation of ethanol with conversion levels of 56% and 71%, respectively, at 400oC for an O2/EtOH feed ratio of 0.5. Both catalysts had very high selectivities to acetaldehyde at temperatures below 300oC. Conversions exceeded 95% with the V-MCM-41 catalyst having a V/Si molar ratio (in the solid) of 0.04 in the temperature range of 300oC-375oC for the O2/EtOH feed ratios of 0.5-2.0. Acetaldehyde selectivities changed between 0.82-1.00 at the temperature range of 150oC-250oC. Ethylene, which is listed as a minor side product of the selective oxidation of ethanol in literature, was produced with a maximum yield of 0.66 at 400oC at the O2/EtOH feed ratio of 0.5. This yield is higher than the yields obtained in the industrial ethylene production methods such as thermal cracking and oxidative dehydrogenation of ethane. Besides, the feedstock used in this work is a non-petroleum chemical, namely ethanol, which can be produced from sugar and crop wastes by fermentation. Thus, the findings of this study are also proposed as an alternative ethylene production method from a non-petroleum reactant at lower temperatures with higher yields.


Organic acids production from cheese-whey
Türkmenoğlu, Seçil; Demirer, Göksel Niyazi; Department of Environmental Engineering (2006)
In this study, production of organic acids from cheese-whey was studied. Optimization of organic acids production was performed in semi-batch and batch reactors. Two sets of experiments were performed. First set of experiments were performed in semi-batch reactors for the optimization of organic loading rate (OLR) and hydraulic retention time (HRT). As a result of Set 1 experiments optimum OLR was found to be 15 g COD l-1. Second set of experiments were performed in batch reactors by using the optimum OLR f...
Vanadium incorporated high surface area MCM-41 catalysts
Gucbilmez, Y; Doğu, Timur; Balci, S (Elsevier BV, 2005-02-28)
High surface area MCM-41 (1452 m(2)/g) and V-MCM-41 materials were synthesized by a direct hydrothermal synthesis method. Characteristic XRD patterns, SEM and AFM photographs indicated no significant change in the morphology of MCM-41 by incorporation of vanadium. XPS and EDS results proved that incorporation of vanadium into the MCM-41 structure was successfully achieved when vanadyl sulfate hydrate was used as the vanadium source. However, use of ammonium vanadate as the vanadium source was not equally su...
Production of thermostable beta-galactosidase from tyhermophilic fungi for use in low-lactose milk production
Soydan, Meltem; Ögel, Zümrüt Begüm; Department of Food Engineering (2006)
The aim of this research was the production of beta-galactosidase from thermophilic fungi for use in low lactose milk production or other possible applications. For this purpose, three thermophilic fungi Humicola insolens, Torula thermophila and Thermomyces lanuginosus were screened for lactase production. Highest lactase activity was observed in Thermomyces lanuginosus. The carbon source inducing highest extracellular lactase production in Thermomyces lanuginosus was determined as arabinose. When grown on ...
Dynamic and steady-state analysis of oxidative dehydrogenation of ethane
Karamullaoğlu, Gülsün; Doğu, Timur; Department of Chemical Engineering (2005)
In this research, oxidative dehydrogenation of ethane to ethylene was studied over Cr-O and Cr-V-O mixed oxide catalysts through steady-state and dynamic experiments. The catalysts were prepared by the complexation method. By XRD, presence of Cr2O3 phase in Cr-O; and the small Cr2O3 and V2O4 phases of Cr-V-O were revealed. In H2-TPR, both catalysts showed reduction behaviour. From XPS the likely presence of Cr+6 on fresh Cr-O was found. On Cr-V-O, the possible reduction of V+5 and Cr+6 forms of the fresh sa...
PAMAM Dendrimer Coated MNPs for siRNA Delivery and Gene Silencing
Unsoy, Gözde; Yalçın Azarkan, Serap; Khodadust, R; Parsiyan, M; Mutlu, P; Bayanbold, H; Gündüz, Ufuk (2014-04-01)
In this study, superparamagnetic iron oxide nanoparticles were synthesized by co-precipitation method. The synthesized nanoparticles were modified with aminopropyl-trimethoxysilane for dendrimer coating. Aminosilane-modified MNPs were coated with PAMAM dendrimer. Gene silencing effect of Survivin siRNA loaded nanoparticles (NPs) were studied on Doxorubicin resistant MCF-7 cell lines. Consequently, Survivin siRNA were triggered cell death when delivered by G4 PAMAM dendrimer coated magnetic nanoparticles. Su...
Citation Formats
Y. Güçbilmez, “Vanadium and molybdenum incorporated mcm-41 catalysts for selective oxidation of ethanol,” Ph.D. - Doctoral Program, Middle East Technical University, 2005.