Browsing by Author "Gumus, Ilkay"

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Design of Novel Binuclear Phthalocyanines Formed by Dioxyphenyl Bridges: Synthesis and Investigation of Thermal and Antioxidant Properties
(Wiley-v C H verlag Gmbh, 2012) Agirtas, M. Salih; Gumus, Ilkay; Okumus, Veysi; Dundar, Abdurrahman
4, 4'-(1, 4-Phenylenebis(oxy)diphthalonitrile was synthesized by reaction of hydroquinone with 4-nitrophthalonitrile. Binuclear metallophthalocyanines 24 were obtained by the reaction between 4, 4'-(1, 4-phenylenebis(oxy)diphthalonitrile and 4-(benzo [d] 1,3 dioxol-5-ylmethoxy)phthalonitrile in the presence of metal salts. These new compounds were characterized by using elemental analysis, FTIR, 1H-NMR and UV/Vis spectroscopic data. Thermal properties of phthalocyanines 2-4 were investigated by TG and DTA. In addition, antioxidant properties of compounds II, 3 and 4 were investigated. Their radical-scavenging capacity and chelating effects was fully studied. The maximum 1, 1-diphenyl-2-picrylhydrazyl radicals (DPPH) were obtained from compound 3. Chelating effects on ferrous ions were 91.6?% at concentration of 100 mg?L1 with compound II.
Designing of New Thermo Stabile Phthalocyanines: Synthesis, Characterization, and Thermal Studies
(Taylor & Francis inc, 2012) Agirtas, M. Salih; Gumus, Ilkay; Izgi, M. Sait
In this study, new phthalonitrile and phthalocyanines were synthesized and characterized. Starting material compound 3 was obtained by reaction of ninhydrin with 4-nitrophthalonitrile. Phthalocyanines 4-8 were prepared by reaction 4-(2-phenoxy-1, 3-dioxo-2, 3-dihydro-1H-inden-2-yloxy) phthalonitrile with corresponding metal salts. Compound 9 was obtained by reaction of phthaocyanine 4 with NaOH. This compound is soluble in water as sodium salts. Thermal properties of compounds 3-8 were investigated by TG and DTA. Thermal stabilities of compounds 4-8 are also reported. The novel compounds were characterized by elemental analysis, FTIR, H-1-NMR, and UV-VIS spectral data.
Green and Efficient Oxidative Desulfurization of Refractory S-Compounds From Liquid Fuels Catalyzed by Chromium-Based Mil-101 Stabilized Moox Catalyst
(Elsevier, 2022) Gumus, Ilkay; Karatas, Yasar; Gulcan, Mehmet
In this work, MoOx/MIL-101(Cr) a new composite material, involving the collaboration of MoOx and MIL-101 (Cr) to remove the refractory S-compounds (RSCs) from fuels via oxidative desulfurization (ODS) process were successfully synthesized. The prepared catalyst was characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), powder X-ray diffraction (P-XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES), fourier transform infrared spectroscopy (FT-IR), N-2 sorption measurement (BET) and X-ray photoelectron spectroscopy (XPS). The prepared MoOx/MIL-101(Cr) was applied for the ODS of model fuel oil and showed the remarkably catalytic activity for the removal of RSCs from model fuel oil via oxidation. In addition, the effect of Mo-loading amount, H2O2/sulfur (O/S) molar ratio, and reaction temperature on the ODS reactivity were investigated. To explore the specific reaction mechanism of ODS over the MoOx/MIL-101(Cr), the effect of radical scavengers on ODS activity was examined. The radical scavengers experiments showed that the present oxidation reaction occurred through a radical mechanism involving the formation of center dot OH and center dot O-2 species. In addition, it was found that the ODS efficiency is majorly related to the Mo5+ species forming with electron transfer to Mo6+ ion from Lewis acid sites of MIL-101(Cr). Furthermore, the MoOx/MIL-101(Cr) catalyst possesses recycling performance and remarkable stability, and even after five recycles, the removal of DBT was > 94.8%. Hence, it could be confirmed that MoOx/MIL-101(Cr) is very useful in the ODS to remove RSCs from fuels in the presence of H2O2.
Highly Efficient and Selective One-Pot Tandem Imine Synthesis Via Amine-Alcohol Cross-Coupling Reaction Catalysed by Chromium-Based Mil-101 Supported Au Nanoparticles
(Elsevier, 2021) Gumus, Ilkay; Ruzgar, Adem; Karatas, Yasar; Gulcan, Mehmet
One-pot tandem synthesis of imines from alcohols and amines is regarded as an effective, economic and green approach under mild conditions. In this work, Au nanoparticles (NPs) dispersed on MIL-101 (Au/MIL-101) were demonstrated as highly active and selective bifunctional heterogeneous catalyst for production of various imine derivatives with excellent yields, via amine-alcohol cross-coupling reaction at 343 K in an open flask under an Ar atmosphere. Various physicochemical techniques, including inductively coupled plasma optical emission spectroscopy (ICP-OES), powder X-ray diffraction (P-XRD), X-ray photoelectron spectroscopy (XPS) transmission electron microscopy (TEM) and N2 adsorption-desorption, were used to characterize of the Au/MIL-101 catalyst. The obtained bifunctional catalyst is highly active and selective towards one-pot imine formation and exhibited the highest TOF (30.15-51.47 h(-1)) among all the ever-reported MOF-supported Au catalysts. The reaction mechanism of the imine formation from alcohol and amine over Au/MIL-101 catalyst was proposed. Mechanism experiment results demonstrate that Au NPs highly effective in activating oxidation of benzyl alcohol to benzaldehyde while the Lewis acid sites on MIL-101 catalyzed the second condensation step without interfering with the oxidation step. As a result, the excellent catalytic performance of Au/MIL-101 can be ascribed to the synergistic effect between Au NPs with Lewis acid sites in MIL-101.
Silver Nanoparticles Stabilized by a Metal-Organic Framework (mil-101(cr)) as an Efficient Catalyst for Imine Production From the Dehydrogenative Coupling of Alcohols and Amines
(Royal Soc Chemistry, 2020) Gumus, Ilkay; Karatas, Yasar; Gulcan, Mehmet
In this paper, we present silver nanoparticles supported on a metal-organic framework (Ag@MIL-101) as a catalyst for the one-pot tandem synthesis of imines from alcohols and amines. The Ag@MIL-101 catalyst was fabricated using the liquid phase impregnation technique as an easy and effective method. The morphology and chemical structure of the prepared catalyst were systemically evaluated by inductively coupled plasma optical emission spectroscopy (ICP-OES), powder X-ray diffraction (P-XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The highly crystalline feature of the Ag metal nanoparticles on bifunctional MIL-101(Cr) was revealed by TEM and HRTEM analyses. The Ag@MIL-101 catalyst was examined as a catalyst for the synthesis of different imine derivatives. The catalytic performance of the Ag@MIL-101 catalyst was monitored by GC-MS and(1)H-NMR analyses for the dehydrogenative coupling of alcohols and amines. Furthermore, the effect of various factors such as the amount of catalyst, base, temperature and solvent was investigated to optimize the conditions for the best performance of the Ag@MIL-101 catalyst. Catalytic activity test results showed that the Ag@MIL-101 catalyst has a good catalytic activity with TOF values in the range of 12.7-14.6 h(-1)in the synthesis of various imines.
Ti3c2tx Mxene for Removal of S-Compounds From Model Fuel Oil Via the Fenton-Like Reaction
(Elsevier Sci Ltd, 2024) Gumus, Ilkay; Gulcan, Mehmet
The desire to mitigate the release of harmful SOx x emissions resulting from fuel combustion is driving the advancement of desulfurization technology. This technology aims to enable the widespread production of ultraclean fuel on a large scale. The utilization of H2O2 2 O 2 as an oxidant in oxidative desulfurization has become a feasible method for desulfurizing petroleum distillates without releasing carbon. However, some difficulties need to be addressed, such as excessive consumption of oxidants at high temperatures, low efficiency caused by immiscibility between water and oil, and high interfacial tension. This study demonstrates the application of an Ti3C2Tx 3 C 2 T x MXene catalyst for the oxidative removal of S-compounds at 298 K with low H2O2 2 O 2 via a Fenton-like reaction, which has not been reported before. This was achieved using a biphasic system that facilitated the access of H2O2 2 O 2 molecules to Ti sites with oxygen vacancies on MXene, resulting in the formation of dynamically active species. Remarkably, the utilization of both a polar solvent and an optimal quantity of H2O2 2 O 2 resulted in the enhanced diffusion and attraction of H2O2 2 O 2 to the active sites, thereby creating a favorable hydrophilic environment. Consequently, this forms a localized reaction setting that encompasses electron-rich Ti active sites, along with H2O2 2 O 2 and S-compounds, facilitating an effective ODS reaction. By maintaining a low content ratio of H2O2/S 2 O 2 /S = 4, it was possible to eliminate 1000 ppm of dibenzothiophene (DBT) from the model oil within just 30 min at ambient temperature.