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  • 1
    Electronic Resource
    Electronic Resource
    Ga2O3/HZSM5 propane aromatization catalysts. Influence of the hydrogen pretreatment on the acid and redox functions (1993)
    Springer
    Catalysis letters 21 (1993), S. 275-281 
    Details
    ISSN: 1572-879X
    Keywords: Propane ; aromatics ; acid catalysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The activity and selectivity of a mechanical Ga2O3/HZSM5 mixture in four model reactions (propane aromatization at 803 K,n-heptane cracking and meta-xylene isomerization at 623 K, methylcyclohexane transformation at 773 K) were compared after pretreatment at 873 K under nitrogen and under hydrogen flow. It was thus demonstrated that the hydrogen treatment provoked a significant increase in the dehydrogenating activity of the gallium species but only a small decrease in the protonic acidity. Moreover this hydrogen treatment created a significant hydrogenolysis activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00769479
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of alkanes on the o-xylene transformation on Y zeolite (1983)
    Springer
    Reaction kinetics and catalysis letters 22 (1983), S. 237-239 
    Details
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Добавление изопарафинов к о-ксилолу уменышает скорость его диспропорционирования, но не оказывает какого-либо эффекта на изомеризацию. Ингибирующий эффект является следствием реакции бензильных карбокатионов, промежутоиных соединений диспропорционирования, с изопарафинами, приводящей к уменьшению концентрации первых. Никакого эффекта не наблюдается при добавлении н-алканов, взаимодействие которых с бензильными карбокатионами давало бывторичные ионы карбена, являющиеся менее стабильными по сравнению с третичными ионами, образующимися из изопарафионов.
    Notes: Abstract Adding isoparaffins to o-xylene decreases its rate of disproportionation but has no effect on isomerization. This inhibiting effect is due to a reaction between the benzylic carbocations, intermediates of disproportionation, and isoparaffins with reduction of their concentration. No effect is observed by adding n-alkanes whose reaction with benzylic carbocations would give secondary carbenium ions much less stable then the tertiary ones formed from isoparaffins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02064839
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Dealumination of the outer surface of MFI zeolites by ammonium hexafluorosilicate (1995)
    Springer
    Reaction kinetics and catalysis letters 54 (1995), S. 209-215 
    Details
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The treatment of MFI zeolites with ammonium hexafluorosilicate causes a selective dealumination of their outer surface. This dealumination improves the selectivity to the para isomer of m-xylene isomerization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02071200
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  • 4
    Electronic Resource
    Electronic Resource
    Toluene disproportionation and coke formation over fluorided alumina and hydrogen-mordenite (1980)
    Springer
    Reaction kinetics and catalysis letters 13 (1980), S. 183-189 
    Details
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Превращения толуола были исследованы на фторированной окиси алюминия и протонированном мордените в водороде (0,8, 12 бар) и в азоте (12 бар). Давление водорода значительно улучшает каталитическую стабильность Н-морденита, интибируя образование кокса. Однако, водород исключает часть кокса, выделяющегося реакцией в азоте, и восстанавливает активность морденита. В противоположность этому, водород не оказывает какого-либо эффекта в случае фторированной окиси алюминия. Особое поведение морденита приписывается его очень сильной кислотности.
    Notes: Abstract Toluene transformation was investigated on a fluorided alumina and a protonic mordenite under hydrogen (0.8, 12 bar) and under nitrogen (12 bar). Hydrogen pressure considerably improves the catalytic stability of H-mordenite by inhibiting the formation of coke. Moreover, hydrogen eliminates part of the coke deposited by reaction under nitrogen, and regenerates the activity of the mordenite. On the contrary, hydrogen has no effect in the case of fluorided alumina. The particular behavior of the mordenite is attributed to its very strong acidity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02068564
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    Paper (German National Licenses)
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