Dobiesław Nazimek

The influence of boron atoms on the surface of controlled porous glasses on the properties of the carbon deposit obtained by pyrolysis of alcohol

Abstract Controlled porosity glasses are often used as molecular sieves in columns for gel permeation chromatography or as supports of chemically bonded bioactive ligands for affinity chromatography and alkyl chains for reversed-phase chromatography. They can also be used as supports of adhesively deposited ligands or solid films. One of the characteristic features of controlled porosity glasses is the presence of boron atoms on their surface, the concentration of which can easily be changed by appropriate thermal treatment. This paper deals with the properties of the carbon deposit obtained by pyrolysis of n -decanol on a glass surface with different amounts of boron atoms.

Properties of the material surfaces obtained by pyrolysis of alkanols on boron-enriched controlled porous glasses

Abstract Controlled porous glasses (CPG) are often employed as packing materials for gas and liquid chromatography. The characteristic feature of CPG is the presence of surface boron atoms, the concentration of which can easily be changed by appropriate thermal treatment. The use of thermally treated CPG as a support in the pyrolysis of alcohols causes the formation of graphite in the carbon deposit obtained. The properties of thermally treated CPG and the same CPG with a carbon deposit on their surface was investigated by means of the hydrogenolysis reaction of n -butane. The results obtained suggest that the pyrolysis of a constant molar amount of alkanols differing in their chain lengths leads to blocking of the same centres on the CPG surface.

Hydrogenolysis of n-butane over Ru/SiO2 catalysts of high ruthenium dispersity

Ruthenium catalysts Ru/SiO2 were obtained from 2RuOHCl2. 7NH3 solution by means of ion exchange between the OH groups on the SiO2 surface and using classical impregnation from acid RuCl3 solution. The measurement of the rate of n-butane hydrogenolysis was carried out in a gradientless reactor. Measurements were made within the temperature range of 470–670 K at H2∶C4H10 ratio equal to 6∶1. The results obtained indicate a definite influence of the dispersity of ruthenium on the reaction rate of the hydrogenolysis of n-butane and on the selectivity of this process. The effect of the degree of Ru dispersity on the rate of n-butane hydrogenolysis was examined A correlation was found between the dispersity of Ru and the selectivity to methane, ethane and propane.AbstractРутениевые катализаторы Ru/SiO2 были получены из раствора 2RuOHCl2. 7NH3 с помощью ионного обмена с группами OH на поверхности SiO2 и, используя классическое импрегнирование из кислых растворов RuCl3. Измерение скорости гидрогенолиза н-бутана проводилось в реакторе без градиента. Измерения велись в интервале температур 470–670 К при отношении H2∶C4H10, равном 6∶1. Полученные результаты свидетельствуют об определенной зависимости мэжду дисперсностью рутения и скоростью реакции гидрогенолиза н-бутана, а также селективностью этого процесса. Было исследовано влияние степени дисперсности на скорость гидрогенолиза н-бутана. Была найдена корреляция между дисперсностью Ru и селективностью к образованию метана, этана и пропана.

Hydrogenolysis of n-Butane over Ru/Al2O3 Catalysts

Preliminary studies were undertaken of the preparation parameters of DIM (double impregnation method) influencing metal loading, ruthenium catalyst dispersion and n-butane hydrogenolysis. Ruthenium red was used as the metal precursor of Ru/Al2O3 catalysts. The infrared spectra of ruthenium red and EDTA adsorbed on alumina indicated that interaction occurs between adsorbates and the support surface. An extension of the impregnation time by ruthenium red caused a slight shift of the asymmetric –COO− band that may be explained by interaction between ruthenium and adsorbed EDTA. The small change in the –COO− band position was due to the nature of the metal–EDTA bond formed. An increase in metal loading led to an increase in ruthenium dispersion. Measurements of the rate of hydrogenolysis of n-butane were carried out in a gradientless reactor. All kinetic experiments were conducted under conditions where the hydrogen/n-butane molar ratio was 9:1, and involved isothermal determination of the relationship between the n-butane reaction rate and the corresponding degree of conversion (iso-X). The absence of propane and the presence of isobutane (at lower temperature) among the products were discussed.

Hydrogenolysis of ethane over Ni/Al2O3 catalysts of high nickel dispersity

The effect of nickel dispersity on the rate of ethane hydrogenolysis and the number of B5 centers has been studied. A maximum in the rate of ethane hydrogenolysis is observed in the range of nickel dispersity of 2–3.5 nm. There is a minimum of the apparent activation energy of ethane hydrogenolysis in this range of metal crystallite size.AbstractИсследовано влияние степени дисперсии никеля на скорость гидрогенолиза зтана и число центров В5. Максимальная скорость гидрогенолиза зтана была достигнута в области дисперсий никеля 2–3,5 нм. В зтой области размеров металлических кристаллитов наблюдался минимум кажущейся знергии активации гидрогенолиза зтана.

Influence of the vanadium and zinc contents in DESONOX catalysts on the course of the DESOX reaction

The catalytic process of SO2 removal from combustion gases takes place on the grain plane of hard coal. This process is competitive relative to classical desulphurization processes. The method proposed for the removal of SO2 from combustion gases described in this paper is quite different from wet classical desulphurization methods. This paper reports studies of the influence of vanadium and zinc concentration on the catalytic activity of a number of DESONOX catalysts (in the course of the DESOX reaction). Investigations of the influence of the total surface area and other physicochemical properties of the catalyst on its behaviour are also reported.

Influence of Added Molybdenum on the Activity of DESONOX Catalysts

The catalytic removal of SO2 from combustion gases has been studied on the grain plane of a hard coal, being competitive with classical desulphurization processes. The method proposed for the removal of SO2 from combustion gases described in this paper is quite different from wet classical desulphurization methods. Studies of the influence of molybdenum concentration on the catalytic activity of a number of DESONOX catalysts are reported. The influence of the total surface area and other physicochemical properties of the catalyst on its behaviour have been studied.

The influence of nickel dispersion in Ni/Al2O3 catalysts on their properties in the reaction with hydrogen, hydrocarbons and steam

Nickel catalysts are commonly used in many industrial processes including the hydrogenation, hydrotreating, hydrogenolysis, methanation and steam reforming of hydrocarbons. The aim of the present paper was to describe the influence of various physicochemical properties of nickel-supported catalysts on the course of coking in the steam reforming of n-butane as well as the influence of the concentration of B5 sites on the surface of the catalyst on the course and mechanism of the hydrogenolysis of simple alkanes.

Hydrogenolysis of n-butane on Ni-Pd/SiO2 catalysts

Supported Ni-Pd/SiO2 catalysts of different Ni and Pd composition were studied in n-butane hydrogenolysis. The reaction rate, selectivity towards methane, ethane and propane were determined. On the basis of these data the relationship between the size and composition of the active center and the possibility of surface segregation of one of the components is discussed.AbstractКатализаторы на носителях Ni-Pd/SiO2 изучены при различных содержаниях Ni и Pd в гидрогенолизе н-бутана. Определены константы скорости и селективность к метану, этану и пропану. На основе полученных данных обсуждается зависимость между размером и составом активных центров и возможностью поверхностной сегрегации одного из компонентов в системе.

Alumina as a nickel catalysts support for steam reforming of hydrocarbons

The coking resistance of six alumina supported nickel catalysts in n-butane steam reforming mainly depends on the average size of nickel crystallites. Thus, by using suitable preparative methods, it is possible to produce good, coking resistant nickel catalysts even with Al2O3 support.AbstractУстойчивость к коксованию шести никелевых катализаторов на носителе Al2O3 при паровом риформинге н-бутана, в основном, зависит от средних размеров никелевых кристаллитов. Т. О., используя подходящие препаративные методы, оказалось возможным производство хороших коксо-устойчивых никелевых катализаторов также на носителе Al2O3.