Papers by Wlodzimierz Zmierczak
Studies in Surface Science and Catalysis, 1991
Summary Molybdenum sulfide and nickel-molybdenum sulfide catalysts were prepared from Mo(CO) 6 en... more Summary Molybdenum sulfide and nickel-molybdenum sulfide catalysts were prepared from Mo(CO) 6 encaged in Y and stabilized HY zeolites. These catalysts were characterized by XRD, IR, ESR spectroscopy and NO sorption capacity. Mo(CO) 6 based catalysts are highly reactive in water-gas shift reaction and this is related to the high dispersion of molybdenum sulfide. Ni and Mo containing zeolites indicate the existence of synergetic effect. The synergy is confirmed by the presence of a band at 2082 cm −1 during adsorption of CO. Catalysts prepared from dealuminated supports show low activity, mainly due to the limited access of molybdenum carbonyl into the zeolite cavities. ESR spectroscopy indicates the formation of sulfur chain biradicals after interaction of H 2 S with molybdenum containing supports.
Chemischer Informationsdienst, 1980
Studies in Surface Science and Catalysis, 1993
ABSTRACT The ability of Y zeolites containing nickel and molybdenum to catalyze the water-gas shi... more ABSTRACT The ability of Y zeolites containing nickel and molybdenum to catalyze the water-gas shift reaction with the sulfided feed was tested. Sulfided Ni-Mo-Y catalysts and zeolitic supports were characterized by the NO, NH3, BF3 sorption capacity and by the capability to decompose diacetone and isopropyl alcohols. The influence of acid-base properties of studied catalysts on their activity in the WGS reaction was considered. It has been found that high WGS activity is caused not only by the synergy between Ni and Mo sulfided species but is also influenced by the the acidic OH groups originating both from the support itself and dissociative adsorption of hydrogen sulfide.
Studies in Surface Science and Catalysis, 1991
Abstract Sulfided Mo-Y and Ni-Mo-Y catalysts were tested in thiophene hydrodesulfurization and hy... more Abstract Sulfided Mo-Y and Ni-Mo-Y catalysts were tested in thiophene hydrodesulfurization and hydrogenation of pentene-1 and cyclopentene. Catalysts were prepared by thermal decomposition of supported Mo(CO)6 encaged in Y and stabilized Y zeolites. Cracking ability in both reactions is related to the surface acidity of catalysts but is not parallel to their HDS activity. H2S generates protonic acidity over NaY and KY zeolites. Synergetic effect between Ni and Mo sulfided species in HDS reaction was observed. The presence of extra-lattice aluminum in stabilized forms of Y-zeolites favours selectivity towards formation of isopentane and cyclopentane during hydrogenation.
Studies in Surface Science and Catalysis, 1991
Summary Sulfided Mo-Y and Ni-Mo-Y zeolites were tested in the water-gas shift reaction. Sodium, p... more Summary Sulfided Mo-Y and Ni-Mo-Y zeolites were tested in the water-gas shift reaction. Sodium, potassium, cesium and stabilized Y-zeolites were applied as the supports for molybdenum hexacarbonyl. Supported Mo(CO) 6 after partial decarbonylation at 425 K was subsequently sulfided with H 2 S/H 2 mixture. High dispersion of sulfided molybdenum species was found to be one of the factors responsible for the high activity. Deactivation of the highly active catalysts, characterized by the presence of Br nsted acid sites, was mainly caused by the formation of carbonaceous deposits formed from the organic compounds present in the feed.
Zeolites, 1991
ABSTRACT Molybdenum zeolites have been prepared by the interaction of NaY and HNaY zeolites with ... more ABSTRACT Molybdenum zeolites have been prepared by the interaction of NaY and HNaY zeolites with ammonium heptamolybdate or molybdenum hexacarbonyl. After sulfidation with H2S, these zeolites were tested by hydrodesulfurization of thiophene and the water-gas shift reaction. The measurements of NO adsorption indicated that the samples prepared from Mo(CO)6 form catalysts with better dispersion of molybdenum sulfide than those prepared with ammonium heptamolybdate. Mo(CO)6-based catalysts were also more active in both reactions. High reactivity in the water-gas shift reaction was observed for sulfided MoHNaY zeolites prepared from Mo(CO)6. E.s.r. measurements indicated significant differences between the two methods of molybdenum-loading into Y-zeolites. A Mo(V) signal appeared only for the samples prepared from ammonium heptamolybdate.
ChemInform, 2010
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Bulletin des Sociétés Chimiques Belges, 2010
A series of Mo/Al2O3 catalysts were prepared containing various levels of Mo, several different A... more A series of Mo/Al2O3 catalysts were prepared containing various levels of Mo, several different Al2O3 supports, and by different solution pH's. Sulfided catalysts were characterized by NO chemisorption, SH content and thiophene HDS activity. Uptake of NO depended on the temperature of adsorption employed, and consequently an absolute number of adsorption sites could not be determined. Also, correction for NO adsorption on the support was needed to obtain values representative of the MoS2 species present. Assuming NO adsorbs at edge sites of the MoS2 slabs, it was found that the size of the MoS2 slabs was affected by the nature of the Al2O3 support but only slightly by the pH of the impregnating solution. Residual SH content roughly correlated with net NO adsorption. HDS activity was roughly proportional to net NO adsorption and to residual SH content. Significant deviations, however, were observed, indicating that catalytic activity is not precisely related to either.
A process for converting the lignin in residues from biomass-to-ethanol processes was developed. ... more A process for converting the lignin in residues from biomass-to-ethanol processes was developed. High yields of depolymerized lignin (60-80%) were obtained at moderate temperatures and short reaction times. Standard tests for distillation (ASTM D86) and vapor pressure (ASTM D5191) showed that the products are close to meeting these gasoline specifications. Standards tests (ASTM D2700 and D2699) of 19- 50% blends of HPR-BCD products with unoxygenated gasoline gave blending octane numbers for the products of 82-97. Higher values were obtained when hydrogenation is limited, minimizing formation of naphthenes.
Phosphorus and Sulfur and the Related Elements, 1981
Dans le présant travail nous avons étudié la solubilité de SO2 dans l'acide sulfurique co... more Dans le présant travail nous avons étudié la solubilité de SO2 dans l'acide sulfurique concentré enfonction de la pression et de la température. En se basant sur cette étude nous avons établie la formule empirique permettant les calculs de la quantite de SO2 dilué dans H2SO4 pour une certaine pression et une certaine température.The dependence of SO2 solubility in concentrated
Surface Technology, 1984
Abstract The porous structures of FeCr2O4, CoCr2O4 and NiCr2O4 as well as of the products of thei... more Abstract The porous structures of FeCr2O4, CoCr2O4 and NiCr2O4 as well as of the products of their activation with potassium ions (up to 5 mol.% K2O) were investigated. The nature of porosity of the above solids appeared to be polydispersive. Potassium ions, introduced during syntheses of these spinel-type compounds, caused an increase in the volume of the micropores and mesopores.
Reaction Kinetics & Catalysis Letters, 1991
Six MoS2/SiO2 samples were characterized by XRD, BET surface area, ESR and NO adsorption measurem... more Six MoS2/SiO2 samples were characterized by XRD, BET surface area, ESR and NO adsorption measurements. Correlation was found between the amount of Mo5+, sulfur radicals and adsorption capacity for oxygen and NO.AbstractШесть образцов MoS2/SiO2 характеризовали РВД, БЭТ, поверхностной площадью, ЭПР и адсорбцией NO. Наблюдали зависимость между Mo5+, радикалами серы и адсорбционной емкостью к кислороду и NO.
Reaction Kinetics & Catalysis Letters, 1994
ABSTRACT This study is concerned with the effect of various amounts of Sn species in modifying th... more ABSTRACT This study is concerned with the effect of various amounts of Sn species in modifying the dispersity of Al2O3−SnO2 supported platinum catalysts by application of hydrogen chemisorption in a pulse chromatographic system, as well as determination of activity in water-gas shift reaction (WGS).
Fuel, 1998
The catalytic conversion of coal liquids to desirable gasoline components was modeled by the hydr... more The catalytic conversion of coal liquids to desirable gasoline components was modeled by the hydroprocessing of I-methylnaphthalene. The conversion aims at a maximum yield of non-aromatic high octane gasoline components, i.e. isoparaffins and substituted cyclohexanes and cyclopentanes. Experiments were performed in one or two stages using various catalysts. The highest single-stage conversion was achieved in 10 h with a sulfided NiW/Si02-A1203 catalyst at 325°C and 6.7 MPa with a feed/catalyst ratio of 10: 1. In the two-stage operation,
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Papers by Wlodzimierz Zmierczak