Papers by Marek Marczewski
Reaction Kinetics, Mechanisms and Catalysis
The obtained results show that styrene dimers, which are the primary transition products of PS cr... more The obtained results show that styrene dimers, which are the primary transition products of PS cracking undergo consecutive reactions over acid centers of high acid strength (SiO 2-Al 2 O 3 (45 %);-10.8 \ H O B-7.9) as well as centers of low acid strength (c-Al 2 O 3 ; H O [-3.3) at sufficiently high reaction temperatures (723-773 K). It is proposed that phenylbutenyl carbenium ion obtained due to dealkylation reaction converts into coke by the successive elimination of H ? and Hions, which in turn take part in hydrogen transfer reactions resulting in the hydrogenation of styrene dimers to diphenylbutane. The dealkylation of this compound leads to active c-butylbenzene carbenium ion which is a key intermediate for the formation of indane and naphthalene derivatives.
Reaction Kinetics, Mechanisms and Catalysis
The decomposition of diacetone alcohol to acetone proceeding at 303 K as well as the Cannizzaro t... more The decomposition of diacetone alcohol to acetone proceeding at 303 K as well as the Cannizzaro transformation of benzaldehyde at 323 K leading to benzyl alcohol, can be regarded as useful test reactions in investigating the basic properties of solid catalysts. The minimum basic strength H_min needed to initiate the conversion of diacetone alcohol is within the range of 11.8-13.3, and for benzaldehyde transformation the value is 15.4. The above mentioned test reactions were used to study the basic strength of different solid acid-base catalysts. The conclusions can be presented as follows: (a) solid NaOH and Amberlyst type resin A-26 exhibit basic strength of H_ ≥ 15.4 respectively, the basic centers of A-21 resin possess lower strength 11.8-13.3 ≤ H_ < 15.4; (b) Amberlyst-15, Amberlyst XN 1010, Nafion NR 50 resins and solid sulfuric acid (SSA) possess basic strength of H_ < 11.8-13.3; (c) the basic strength of alumina and magnesia is 11.8-13.3 ≤ H_ < 15.4 whether they have been calcined at 753 K or not.
Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1986
ABSTRACT In the presence of Al2O3/AlCl3 superacid catalysts light alkanes undergo low-temperature... more ABSTRACT In the presence of Al2O3/AlCl3 superacid catalysts light alkanes undergo low-temperature isomerization and decomposition. Isomerization is initiated by attack of a superacid Lewis centre (an Al3+ cation with a pronounced deficit of electrons caused by the adsorption of AlCl3 on an adjacent oxygen anion) on the electrons of an alkane C—H bond. The mechanism of n-alkane decomposition depends on the length of the carbon chain. n-Butane decomposition is catalysed by superacid Lewis centres and proceeds via dimer C8-transition-state cracking. In n-pentane and n-hexane decomposition dimers are not present in any reaction step and these reactions are catalysed by a different type of active centre. These sites (surface-bonded carbenium cations) are formed as a result of superacid Lewis centre attack on the C—C bonds of the alkane.
Reaction Kinetics & Catalysis Letters, 1994
The possibility of methane transformation to higher hydrocarbons in non-oxidizing atmosphere has ... more The possibility of methane transformation to higher hydrocarbons in non-oxidizing atmosphere has been studied. It was found that in the presence of the MnOx-Na/SiO 2-HZSM-5 catalytic system methane can be transformed into aromatics with a yield similar to that reported for oxidative coupling conditions.
Reaction Kinetics & Catalysis Letters, 1995
ABSTRACT The activity of supported manganese oxide catalysts doped with copper, chromium and iron... more ABSTRACT The activity of supported manganese oxide catalysts doped with copper, chromium and iron oxides in methane to higher hydrocarbons transformation in non-oxidizing atmosphere has been studied. Chromium and iron oxides are more effective promoters than copper oxide. Redox centers of dehydrogenation ability are active in methane transformations.
Physical Chemistry Chemical Physics, 2001
... Marek Marczewski*, Marzena Dȩbowiak and Hanna Marczewska. Warsaw Uni ersity of Technology, Ch... more ... Marek Marczewski*, Marzena Dȩbowiak and Hanna Marczewska. Warsaw Uni ersity of Technology, Chemistry Department, Noakowskiego 3, 00-662, Warsaw, Poland. ... Fig. 4 Initial cis/trans pent-2-enes ratio for: (1) alumina ■ and BCl 3 /alumina , (2) silica–alumina (53% SiO ...
Physical Chemistry Chemical Physics, 2003
ABSTRACT Acid properties of the catalysts obtained by the reaction of boron halides solutions wit... more ABSTRACT Acid properties of the catalysts obtained by the reaction of boron halides solutions with silica–alumina containing 87% of SiO2 were studied. It was found that the strength of the acid sites formed depends on boron halide used and the nature of BX3 solvent. The stronger acceptor properties of BX3 the higher acid strength of SiO2(87%)-Al2O3/BX3 catalysts was observed. For the preparations obtained by the action of BX3 1.0 M solutions in CH2Cl2 the following order of superacid properties, conformable with halides acceptor strength, was found: SiO2–Al2O3/BI3&gt;SiO2–Al2O3/BBr3≫SiO2–Al2O3/BCl30. The BX3 solvent basicity influences the acid strength of acid centres formed. The less basic is the solvent used, the higher is the strength of the acid sites formed. The experiments with selective poison of Brønsted acid centres (2,6-di-tert-butylpyridine) proved that superacid and strong acid sites of SiO2(87%)–Al2O3/BX3 catalysts are of protic nature.
Journal of Molecular Catalysis A: Chemical, 1995
ABSTRACT Chemical and catalytic properties of Al2O3SbF5 system has been studied. It was found th... more ABSTRACT Chemical and catalytic properties of Al2O3SbF5 system has been studied. It was found that alumina upon SbF5 adsorption became solid superacid of Brønsted nature, able to catalyze n-pentane low temperature isomerization. The following structure of superacid active center has been postulated: [AlOSbF5]−]H+. The stability of this catalyst was evaluated using time-on-stream theory of catalysts decay and then compared with other Brønsted (Al2O3BF3) and Lewis (Al2O3AlCl3) superacid systems. It was found that Brønsted superacid centers are more stable than Lewis ones.
The Canadian Journal of Chemical Engineering, 1983
The influence of gaseous chlorine on the chemical and catalytic properties of alumina was investi... more The influence of gaseous chlorine on the chemical and catalytic properties of alumina was investigated. CI, reacts both with surface OH groups and with surface oxygen anions possessing electron-donating power, forming ncw surface sites. When such chlorine treatment is performed at a low temperature (293 K), both Lewis and Bronsted acid centres are formed. High temperature chlorination leads exclusively to Lewis acid sites. It is proposed that such Lewis sites are responsible for olefin isomerization reactions. On a Ctudie I'influence du chlore a I'etat gazeux sur les proprittks chimiques et catalytiques de I'alumine. CIz rkagit h la fois avec les groupes OH superficiels et les anions oxygkne superficiels donneurs d'klectrons, et forme de nouveaux sites en surface. Lorsque le traitement au chlore se fait a basse temperature (293 K), il se produit des centres acides de Lewis et de Bronsted. La chloruration a temperature elevee conduit exclusivement aux sites acides de Lewis. II y a lieu de croire que les sites de Lewis sont responsables des reactions d'isomkrisation des olefines. hlorinated alumina exhibits strong acid properties as C well as interesting catalytic features. Such catalysts may be obtained by chlorination of an alumina surface using
Polish journal of chemistry
ABSTRACT
Journal of Molecular Catalysis, 1979
ABSTRACT The formation and transformation of an active site for the carbonylation of methanol in ... more ABSTRACT The formation and transformation of an active site for the carbonylation of methanol in the gas phase have been studied for various catalytic systems composed of Al2O3, Al2O3·SiO2, SiO2 or TiO2 as supports and RhCl3 as the active agent. It has been found that oxide supports with pronounced acid—base properties, such as Al2O3 or Al2O3·SiO2 favour the formation of an anion type of rhodium surface complex [ORh(CO)2Cl]−. On practically neutral supports such as SiO2, only the neutral complex −O → Rh(CO)2Cl is formed, while on TiO2, which exhibits a relatively poor acid—base nature, both types of complexes are detected.
Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1980
ABSTRACT Physico-chemical and catalytic properties of alumina exposed to P2O5, AlCl3, CH3AlCl2, P... more ABSTRACT Physico-chemical and catalytic properties of alumina exposed to P2O5, AlCl3, CH3AlCl2, PCl3, PCl5 and H2PO3F vapours have been studied. Catalysts obtained by treatment with P2O5, AlCl3 and CH3AlCl2 vapours are marked by very high acidity and catalytic activity which classify them among the solid superacids. From an i.r.investigation of ammonia adsorption coupled with e.s.r. measurements of perylene adsorption it has been demonstrated that solid superacids exhibit Lewis-type acid behaviour.
Journal of the Chemical Society, Faraday Transactions, 1998
ABSTRACT The catalytic properties of solid superacids obtained by the action of the vapour of Gro... more ABSTRACT The catalytic properties of solid superacids obtained by the action of the vapour of Group 4 metal halides on alumina have been related to the electronegativities of the halides used. It was found that the acid strength of the Lewis superacid centres and the reaction pathways of low-temperature pentane isomerization depend on the electron acceptor ability of the metal halide species bonded to the alumina carrier.
Reaction Kinetics, Mechanisms and Catalysis, 2013
The transformations of styrene dimers at 753 K over catalysts possessing Lewis acid centers as we... more The transformations of styrene dimers at 753 K over catalysts possessing Lewis acid centers as well as weak Brønsted sites of H O [ -2.2 (c-Al 2 O 3 ); Lewis acid, weak Brønsted sites of -3.5 \ H O B -2.2 and redox centers (c-Al 2 O 3 -Cr); strong Brønsted sites of -14 \ H O B -3.5 (SiO 2 -Al 2 O 3 (13 %)), strong Brønsted sites of 14 \ H O B -3.5 and redox centers (SiO 2 -Al 2 O 3 (13 %)-Cr) have been studied. It was established that the following surface groups are responsible for the catalytic activity in the transformation of styrene dimers. c-Al 2 O 3 : OH group adjacent to Al 3? cation (alkenyl chain protonation) and Al 3? (allylic anion generation); c-Al 2 O 3 -Cr: Brønsted acid centers originating from chromium ions at high oxidation states (alkenyl chain protonation) and Cr 3? redox sites (allylic cation generation); SiO 2 -Al 2 O 3 (13 %)-Cr: Brønsted acid centers of silica-alumina (alkenyl chain and aromatic ring protonation) and Cr 3? redox sites (allylic cation generation). The protonation of styrene dimer at the alkenyl chain leads to b-cleavage to toluene and a-methylstyrene as well as to styrene and ethylbenzene. The allylic species formed react to the different styrene dimer isomers and through diphenylbutadiene intermediate to coke. The use of methylcyclohexane as solvent for the styrene dimers in the presence of chromium containing catalysts results in the aromatization reaction leading to toluene and hydrogen. The presence of the later reactant in the system causes styrene and a-methylstyrene hydrogenation to ethylbenzene and cumene.
1996 kinetics, optimization of reactions kinetics, optimization of reactions O 0010 04 -053 Kinet... more 1996 kinetics, optimization of reactions kinetics, optimization of reactions O 0010 04 -053 Kinetics of Aromatics Alkylation. A Comparative Study of Phenol and Toluene Alkylation with Methanol. -Physicochemical data of the toluene alkylation reaction with methanol in the presence of γ-Al2O3 and HY zeolites are assessed. Mechanistical aspects are discussed and compared with previous results of phenol alkylation. -(MARCZEWSKI, M.; PEROT, G.; GUISNET, M.; Pol.
Journal of Molecular Catalysis, 1989
ABSTRACT The alkylation of phenol with methanol was studied at 473 K, at atmospheric pressure in ... more ABSTRACT The alkylation of phenol with methanol was studied at 473 K, at atmospheric pressure in a flow reactor, in the presence of ultrastable (US) HY zeolite. The effect of the conversion rate on the product distribution shows that anisole, ortho- and para-cresols (o-/p-cresol molar ratio = 1.5) are the primary products of the reaction. O-alkylation is about three times as fast as C-alkylation. The transformation of the primary products (anisole and o-cresol), pure or in mixture with methanol was also studied under the same conditions. Anisole disproportionates into methylanisoles and phenol. The reaction is assumed to occur through methyl transfer between a protonated and a non-protonated anisole molecule. Direct isomerization of anisole into cresols does not occur. The alkylation of phenol by anisole leads to cresols and methylanisoles as primary products. This reaction is about twice as fast as the disproportionation of anisole. The rate of formation of cresols from phenol apparently does not depend on the alkylating agent (methanol or anisole). However, phenol inhibits anisole disproportionation. Pure o-cresol does not react. Its alkylation by methanol gives mainly o-methylanisole and 2,4- and 2,6-dimethylphenols.
Reaction Kinetics, Mechanisms and Catalysis, 2012
A relation between the acid strength of the active centers of sulfated alumina catalysts and the ... more A relation between the acid strength of the active centers of sulfated alumina catalysts and the results of transformation of styrene dimers was studied. The acid strength measurements were performed according to the test reaction method using a-methylstyrene, styrene, tert-butylbenzene and cumene reactions at 298 K. It was found that acid strength of: alumina is characterized by
Polish Journal of Chemical Technology, 2007
Juvenile Delinquency in Europe and Beyond, 2009
Poland is located in Central Europe, has an area of about 312,000 km2, a population of over 38 mi... more Poland is located in Central Europe, has an area of about 312,000 km2, a population of over 38 million, and is the sixth biggest Member State in the European Union. Following a lengthy period of communist rule, Poland became a parliamentary democracy in 1989, with a market economy, and observing the principle of the rule of law. Poland has been
Journal of the Chemical Society, Faraday Transactions, 1992
ABSTRACT The physico-chemical and catalytic properties of alumina exposed to ZrCl4 vapour have be... more ABSTRACT The physico-chemical and catalytic properties of alumina exposed to ZrCl4 vapour have been studied. It was found that ZrCl4 reacts with both basic surface OH groups and exposed O2– ions forming Lewis superacid centres as well as Brønsted acid sites. The mechanism of n-pentane low-temperature isomerization involving H– abstraction from the alkane has been postulated.
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Papers by Marek Marczewski