ABSTRACT
In this study, Molybdenum precursors were synthesized with Triphenylphosphine, 1,2-Bis(diphenylphosphino)ethane, Pyridine, 2,2-Bipyridine as a ligands. The molybdenum precursors was used for Hydrocraking reaction of Vacuum Residue (VR). Hydrocracking reactions were carried out under the 430 °C and H2 pressure of 80 bar in an 100 ml high pressure reactor. New Molybdenum precursors were tested and their activities were compared with Mo-octoate. The Molybdeum-Phosphine precursor showed the best performances, high yield and low coke contents (below 0,5 wt%), in of hydrocracking for VR. To characterize the physicochemical properties of Moprecursor catalyst, various characterization techniques (NMR, XPS) were carried out. We confirmed that cokes in the reactor were contained the P atoms derived from ligand of Mo-precursor after hydrocracking of VR.
ABSTRACT
In this study, Molybdenum precursors were synthesized with butanoic acid, hexanoic acid, nonanoic acid, decanoic acid, and undecanoic acid. In order to determine chemical structure of Synthesized molybdenum precursors, 1H(13C)-NMR, EA and ICP were used pyrolysis properties were measured TGA. The molybdenum precursors was used for Hydrocracking of Vacuum R1esidue (VR). It was shown that molybdenum nonanoate(3) was shown the lowerst Toluene Insoluble and Gas Product about 2.1 and 5.0 percent.
ABSTRACT
The TiO2 powder was prepared from the spent titanium chips by applying the sol-gel method. The spent titanium chip was dissolved in HCl solution, and then NH4OH solution was added. The molar concentration of NH4OH solution was 2 M, 4 M, 8 M, and 10 M. Obtained TiO2 powders were calcined at 200 degrees C, 400 degrees C, and 600 degrees C. The prepared TiO2 powder was characterized using a particle size analysis, BET surface area, and XRD analysis. The crystal structure of the TiO2 powder was rutile type and anatase. The highest BET surface area of TiO2 powder was 432.8 m2/g. The photocatalytic property of the TiO2 powder was evaluated as decomposition rate of methylene blue(MB) by using a liquid phase stirred reactor. UV source was a UV-A, and concentration of MB in most experiments was 8 ppm. The concentration of MB was measured by absorbance at 664 nm using UV spectroscopy. Photocatalytic efficiency of prepared TiO2 powder depended highly on concentration of NH4OH solution. The TiO2 powder prepared with 8 M-NH4OH solution showed the highest efficiency, the decomposition efficiency at decomposition time of 2 hr and MB concentration of pH 8 was 98%.
ABSTRACT
In this study, titanium chips (TC) generated from industrial facilities was utilized as TiO2 support for hydrogenation of carbon dioxide (CO2) to methyl alcohol (CH3OH) over Cu-based catalysts. Nano-sized CuO and ZnO catalysts were deposited on TiO2 support using a co-precipitation (CP) method (CuO-ZnO/TiO2), where the thermal treatment of TC and the particle size of TiC2 are optimized on CO2 conversion under different reaction temperature and contact time. Direct hydrogenation of CO2 to CH3OH over CuO-ZnO/TiO2 catalysts was achieved and the maximum selectivity (22%) and yield (18.2%) of CH3OH were obtained in the range of reaction temperature 210-240 degrees C under the 30 bar. The selectivity was readily increased by increasing the flow rate, which does not affect much to the CO2 conversion and CH3OH yield.
ABSTRACT
Complexes 1 and 2 were obtained by the reaction of [Cu(L1)](ClO4)2 (1) or [Cu(L2)](ClO4)2 (2) (L1 = 8-acetyl-1,3,6,8,10,13,15-heptaazatricyclo[13.1.1.113,15]octadecane, L2 = 3,7-bis(2-aminoethyl)- 1,3,5,7-tetraazabicyclo[3.3.l]decane) with K2[Pt(CN)4] in water. The X-ray crystal structures show that the geometry around Cu(II) ions of 1 and 2 adopts a square-pyramid. Their one-dimensional and two-dimensional structures are constructed by the intermolecular hydrogen bonding between the macrocyclic ligand and anionic complex ions or water molecules and Pt-Pt interaction. They show luminescent property and luminescence quantum yields are 0.341 and 0.187 for 1 and 2 in solid, respectively.
ABSTRACT
The TiO2 powder was prepared from the spent titanium chips by applying the sol-gel method with neutralization by NaOH solution. The prepared TiO2 powder was characterized using a particle size analysis, BET surface area, and XRD analysis. The crystal structure of the TiO2 powder was rutile type, and the powder was obtained to be nanosized. BET surface area of TiO2 powder was 118 m2/g, average particle size was 266.5 nm. The photocatalytic property of the TiO2 powder was evaluated as decomposition rate of methylene blue (MB) by using a liquid phase stirred reactor. Decomposition rate on TiO2 powder (P-25) was 1.5 times higher than that of the prepared TiO2 powder. Decomposition rate on the prepared TiO2 powder was linearly increased with increasing the amount of TiO2 powder, and approached to a specific value. MB concentration and decomposition rate was not correlated within the experimental range. The maximum value of decomposition rate at about pH 8 was 62%.
ABSTRACT
The greenhouse effect of carbon dioxide (CO2) has been recognized as one of the most serious problems in the world. Conversion of CO2 to methyl alcohol (CH3OH) was studied using catalytic chemical methods. Honeycomb-typed monolith used as catalyst support was 400 cell/inch2. Pretreatment of the monolith surface was carried out by thermal treatment and acid treatment. Monolith-supported nanosized CuO-ZnO catalysts were prepared by wash-coat method. The prepared catalysts were characterized by using SEM, TEM, and XRD. The catalytic activity for CO2 hydrogenation to CH3OH was investigated using a flow-type reactor with varying reaction temperature, reaction pressure and contact time. Conversion of CO2 was increased with increasing reaction temperature, but selectivity to CH3OH was decreased. Optimum reaction temperature was about 250 degrees C under 20 atm. Because of the reverse water gas shift reaction.
Subject(s)
Carbon Dioxide/chemistry , Chemistry Techniques, Synthetic/instrumentation , Chemistry Techniques, Synthetic/methods , Copper/chemistry , Methanol/chemistry , Zinc Oxide/chemistry , Equipment Design , HydrogenationABSTRACT
In order to reutilize spent metallic titanium chips (TC) as catalyst support or photocatalytic materials, the surface of the TC was modified by thermal treatment under air atmosphere. TC-supported nanosized CuO and ZnO catalysts were prepared by impregnation (IMP) and co-precipitation (CP) method, respectively. The catalytic activity for CO2 hydrogenation to CH3OH was investigated using a flow-typed reactor under various reaction pressures. The crystals of CuO and ZnO was well formed on TC. CO2 conversion, CH3OH selectivity, and CH3OH yield were obtained as a function of time on stream over CuO-ZnO/TC catalysts. Conversion of CO2 to CH3OH over CuO-ZnO/TC catalyst by CP method and CuO/ZnO/TC catalyst by IMP method were ca. 16% and ca. 12%, respectively. Conversion of CO2 over CuO-ZnO/TC catalyst by CP method was increased with increasing reaction temperature in the range of 15-30 atm. Maximum selectivity and yield to CH3OH over CuO-ZnO/TC at 250 degrees C were ca. 90% at 20 atm and ca. 18.2% at 30 atm, respectively.
ABSTRACT
In order to reutilize the spent metallic titanium chips, TiO2 photocatalysts were prepared using the self-propagating high-temperature synthesis (SHS) method, and were characterized by N2 gas adsorption, X-ray diffraction, and scanning electron microscope, particle size distribution. Also, their photocatalytic activities were evaluated using methylene blue as a model organic compound. It was confirmed that the crystal structure of TiO2 prepared by SHS method was relatively homogeneous powder of rutile type. Optimum conditions for photocatalytic degradation of methylene blue under UV-C irradiation were methylene blue 9.5 ppm in solution and at amount of TiO2 added of 0.02 g/L. In addition, it was found that the photocatalytic activity for methylene blue degradation over the prepared TiO2 particles was positively related with BET specific surface area.
ABSTRACT
Platinum complexes [Pt(bpy)Cl2](bpy: 2,2'-bipyridine) and [Pt(PT)Cl2](PT: 1,10-phenantroline) were reacted with 5,5"-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(2,2'-bipyrine), bpy-spiro-bpy, to afford mono and diplatinium complexes: [(bpy)Pt(bpy-spiro-bpy)][PF6]2, [(bpy)Pt(bpy-spiro-bpy)Pt(bpy)])[PF6]4, and [(PT)Pt(bpy-spiro-bpy)])][PF6]2, which were characterized by NMR, UV/VIS, mass spectrum, and PL spectroscopy. They showed very high internal quantum yields (0.35-0.67) and emitted light in the blue region (473-520 nm). Herein, we describe the synthesis, characterization of the mono- and di-platinum complexes in detail.
ABSTRACT
In this work, the liquid phase plasma reduction method was applied to prepare the spherical nickel nanoparticles from the solution of nickel chloride. A bipolar pulsed power supply was used to generate discharges in the aqueous solutions. Nickel nanoparticle peaks produced by surface plasmon absorption were observed around 381 nm with electrical discharge. Spherical nickel nanoparticles were mostly observed in this study, pentagonal nanoparticles were also observed occasionally. The TEM image showed that the average particle size varied from 10 to 200 nm in diameter as discharge time was increased. Many spots could be seen in the ED pattern for polycrystalline particles.
ABSTRACT
The reaction of the [Pt(bpy-R)Cl2](bpy-R: R=H (2,2'-bipyridine); R=CH3 (4,4'-dimethyl-2,2'-biypridine (DM-bpy), 3,3'-5,5'-tertamethyl-2,2'-bipyridiyl (TM-bpy)) with 1,4-Bis(5'-2',2"-bipyridine)benzene (bpy-Ph-bpy) affords the following mono- and di-platinum complexes of [(bpy)Pt(bpy-Ph-bpy)][PF6]2 (1), [(bpy)Pt(bpy-Ph-bpy)Pt(bpy)])[PF6]4 (2), [(DM-bpy)Pt(bpy-Ph-bpy)])][PF6]2 (3), and [(TM-bpy)Pt(bpy-ph-bpy)[PF6]2 (4), respectively. These complexes were characterized by NMR, IR, UV/VIS, PL and cyclic voltammetry. The internal quantum yields of these platinum(II) complexes are very high (0.83-0.99) and these complexes emit light at deep blue regions (373-417 nm). The redox behavior of complexes 1 and 2 shows quasi-reversible process.
ABSTRACT
The Nanolayered TiO2 photocatalysts were prepared by thermal treatment of metallic titanium chips. Photocatalytic activity for methyl ethyl ketone (MEK) and toluene was investigated using a closed circulating system. The photocatalysts were characterized by SEM and XRD. Surface of the Ti chips changed to be rough with increase of treatment temperature, and severe oxidation over 900 degrees C resulted in TiO2 powder. Uniform TiO2 nanolayer was formed as a rutile type on the metallic chip. Photocatalytic decomposition of MEK over the TiO2 photocatalysts occurred efficiently by UV-C irradiation. The maximum activity for MEK was obtained over Ti Chip treated at 700 degrees C. It was known that the prepared photocatalyts could be applied to remove various VOCs.
ABSTRACT
The effect of water in the reactant gas on the catalytic activity for CO oxidation over Au/Co3O4 catalysts has been investigated. Water in the reactant gas had a negative effect on the catalytic activity for CO oxidation in Au/Co3O4 catalyst. Furthermore, it was observed that the average particle size of gold on Au/Co3O4 catalysts increased after stability testing both in dry and wet conditions.
ABSTRACT
The butadienediyl-bridged complexes [eta5-Cs Me5]Fe(CO)(PPh3)]2 (micro-CH=CH-CH=CH) have been prepared and characterized by cyclic voltammetry, NMR, and X-ray crystallography. Compound 3 diastereomers showed two reversible one-electron oxidations at -0.053 approximately -0.056 V and -0.02 approximately 0.03 V, respectively. The comproportionation constant, Kc, was calculated from these measurements. Kc values are very high, 1.0 approximately 3.0 x 10(9). These values are consistent with the Robin-Day Mixed-Valence Class III.
ABSTRACT
Gold catalysts supported on Co3O4 were prepared by co-precipitation (CP), deposition-precipitation (DP), and impregnation (IMP) methods. The Au/Co3O4 catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (TPR) to understand the different activities for CO oxidation with different preparation methods. Gold particles below 5 nm supported on Co3O4 by DP method were found to be more exposed to the surface than those by CP and IMP methods, and this catalyst was highly active and stable in CO oxidation. Finally, catalytic activity of Au/Co3O4 catalyst for CO oxidation was strongly dependent on the gold particle size.
ABSTRACT
Nanosized TiO2 thin film on the substrate such as stainless steel plate and slide glass film were prepared by magnetron sputtering method, and these TiO2 thin films were characterized by field emission-scanning electron microscopy (FE-SEM). Photocatalytic activity for Methyl-ethyl-ketone (MEK) and acetaldehyde were measured using a closed circulating reaction system through the various ultra violet (UV) sources. From the results of SEM images, nanosized TiO2 thin film was uniformly coated on slide glass, ranging from 360 nm to 370 nm. Photocatalytic activity of MEK over TiO2 thin film on stainless steel plate did not occur by UV-A irradiation, but was efficiently decomposed by UV-B and UV-C. Also, acetaldehyde could be decomposed than MEK. The effect of sputtering conditions on their structure and photocatalytic activities were investigated in detail.
ABSTRACT
The reaction of the iridium dimer [Ir(ppy)2(micro-Cl)]2 (ppy = 2-pyridiylphenyl) with bis(2,2'-bipyridin-5-yl) ethyne (bpy-C2-bpy), bis(2,2'-bipyridine)-butadiyne (bpy-C4-bpy), and bis(2,2'-bipyridin-5-yl-(Z)-hexa-3-ene-1,5-diyl) (bpy-C6H2-bpy) affords the following diiridium complexes: [ClO4]2 [(ppy)2Ir(bpy-C2-bpy)Ir(ppy)2] (1), [ClO4]2 [(ppy)2Ir(bpy-C4-bpy)Ir(ppy)2 (2), and [ClO4]2 [(ppy)2Ir(bpy-C6H6-bpy)Ir (ppy)2 (3), respectively. Herein, we describe the synthesis, characterization, and physical and electrochemical properties of the diiridium complexes in which the two iridium units are connected by a pi-conjugated nanowire bridge.
ABSTRACT
Bimetallic Pt-Au catalysts supported on ZnO/Al2O3 were prepared by incipient wetness impregnation (IW-IMP) method with different pretreatment conditions such as flow velocity, calcination temperature, and heating rate under H2 during the calcination procedure, and characterized by X-ray diffraction (XRD), CO chemisorption, and scanning transmission electron microscopy (STEM) equipped energy dispersive spectroscopy (EDS). Furthermore, catalytic activity for complete oxidation of toluene was measured using a flow reactor under atmospheric pressure. Finally, relationship between the particle sizes with pretreatment conditions and catalytic activity for toluene on the bimetallic Pt-Au catalysts was discussed. In these results, nanosized bimetallic Pt-Au particles on ZnO/Al2O3 could be prepared by IW-IMP method. Relationship between the Pt and Au particle size and activity for toluene oxidation was clearly observed.
ABSTRACT
The reaction of [Ir(ppy)2(micro-Cl)]2 (ppy = 2-pyridiylphenyl) with a substituted bpy ligand (5-bromo-2,2'-bipyridiyl, 5,5'-dibromo-2,2'-bipyridiyl, 5-ethynyl-2,2'-bipyridiyl) affords [Ir(ppy)2R-(bpy)-R'](CIO4) (R = H, R' = Br (1); R = R, R' = Br (2); R = H, R' = ethynyl (3)) in high yield. The structural, physical, and electrochemical properties of the iridium complexes 1, 2, and 3 were characterized by elemental analysis, NMR and optical spectroscopy, cyclic voltammetry, and X-ray structural analysis.