Selectivities of some hydrogenations on metal-modified platinum catalysts

1983 ◽  
Vol 48 (12) ◽  
pp. 3532-3538
Author(s):  
Libor Červený ◽  
Karel Surma ◽  
Vlastimil Růžička ◽  
Ivo Paseka
Keyword(s):  
Atmospheric Pressure ◽  
Surface Coverage ◽  
Platinum Catalysts ◽  
Hydrogenation Rate ◽  
Competitive Hydrogenation

The rates and selectivities of hydrogenation on platinum catalysts modified with monolayers of copper, thallium, lead, or bismuth were studied at 20 °C and atmospheric pressure for the competitive hydrogenation of 1-hexene and 1-undecene in cyclohexane and for the consecutive hydrogenation of 1,5-cyclooctadiene in cyclohexane or ethanol. For the former system, the selectivity was unaffected by the modifying metal and the degree of the surface coverage with the metal, and the relative specific hydrogenation rate decreased only slightly with the degree of surface coverage. For the latter system, the selectivity of hydrogenation to cyclooctene increased with the content of the modifying metal, while the relative specific hydrogenation rate decreased markedly.

Hydrogenation of 2-phenyl-1-propene on platinum black modified with copper

1980 ◽  
Vol 45 (12) ◽  
pp. 3541-3545
Author(s):  
Ivo Paseka ◽  
Libor Červený ◽  
Josef Mach ◽  
Vlastimil Růžička
Keyword(s):  
Reaction Rate ◽  
Surface Coverage ◽  
Platinum Black ◽  
Hydrogenation Rate ◽  
Platinum Surface ◽  
Adsorption Sites ◽  
Pt Black

Copper deposited from a solution of copper(II) formate on Pt-black at surface coverage lower than unity is present on the platinum surface both in the form of ad-atoms and in the form of multiatomic layers. From the dependence of the hydrogenation rate on coverage by copper is followed that the reaction rate depended on the number of free pairs of the adsorption sites of platinum unoccupied by copper.

Competitive Catalytic Hydrogenation in Unsaturated Hydrocarbon Systems With Sterically Hindered Double Bonds

1998 ◽  
Vol 63 (11) ◽  
pp. 1915-1926 ◽  
Author(s):  
Petr Kačer ◽  
Leiv Laate ◽  
Libor Červený
Keyword(s):  
Catalytic Hydrogenation ◽  
Atmospheric Pressure ◽  
Competitive Adsorption ◽  
Supported Catalysts ◽  
Ternary Systems ◽  
Unsaturated Hydrocarbon ◽  
Catalytic Surface ◽  
Competitive Hydrogenation ◽  
Binary And Ternary Systems ◽  
Palladium Platinum

A competitive hydrogenation of unsaturated hydrocarbons (a-methylstyrene, cyclohexene, 1-methylcyclohex-1-ene, 1-tert-butylcyclohex-1-ene and 3-tert-butylcyclohex-1-ene) in binary and ternary systems with palladium-, platinum- and rhodium-supported catalysts in a semibatch isothermal reactor at 20 °C under atmospheric pressure was studied. It was found that considerable variance in selectivity values of competitive hydrogenation in a series of substrates with increasing substituent bulkiness is caused by differences in adsorption and in reactivity of adsorbed molecules. In the case of ternary systems, a change in selectivity of competitive hydrogenation of two substrates was observed, due to the presence of a third substance, caused by a competitive adsorption of all three substrates and their interaction on a catalytic surface.

Competitive hydrogenation of a pair of substrates in combined two-catalyst systems

1984 ◽  
Vol 49 (4) ◽  
pp. 970-975 ◽  
Author(s):  
Libor Červený ◽  
Barbora Vodová ◽  
Vlastimil Růžička
Keyword(s):  
Theoretical Model ◽  
Rate Constants ◽  
Hydrogenation Rate ◽  
Independent Manner ◽  
Competitive Hydrogenation ◽  
Catalyst Systems ◽  
Set Up ◽  
The Individual ◽  
Good Agreement

A theoretical model has been set up for treating competitive hydrogenations of pairs of substrates on combined two-catalyst systems, assuming that the catalysts act in an independent manner. The hydrogenation rate constants of the two substrates and their relative adsorptitives established on the individual catalysts are used for the calculations. the model has been tested on the substrate system of 2-methyl-3-buten-2-ol and 2-phenylpropene, hydrogenated in methanol or cyclohexane on combined Pt/C, Pd/C, and Rh/C catalyst systems. The calculated and observed data are in a good agreement.

Model discrimination in oscillatory CO oxidation on platinum catalysts at atmospheric pressure

2000 ◽  
Vol 459 (3) ◽  
pp. 413-425 ◽  
Author(s):  
C.D. Lund ◽  
C.M. Surko ◽  
M.B. Maple ◽  
S.Y. Yamamoto
Keyword(s):  
Co Oxidation ◽  
Atmospheric Pressure ◽  
Platinum Catalysts ◽  
Model Discrimination

Kinetics of hydrogenation of alkynes and dienes on palladium catalyst

1987 ◽  
Vol 52 (12) ◽  
pp. 2909-2917 ◽  
Author(s):  
Libor Červený ◽  
Šárka Řehůřková
Keyword(s):  
Activated Carbon ◽  
Palladium Catalyst ◽  
Atmospheric Pressure ◽  
Reaction Rates ◽  
Initial Reaction ◽  
Hydrogenation Rate ◽  
Substrate Structure ◽  
The Individual ◽  
Kinetics Of ◽  
Relative Adsorption

Alkynic and dienic substrates (C6-C10) in hexane and methanol were hydrogenated over a catalyst of 3% Pd on activated carbon at 20 °C and atmospheric pressure. The initial reaction rates were measured for the individual substrates; the hydrogenation rates of the olefinic substances formed were also determined if the hydrogenation was selective. The selectivities in competitive hydrogenations of substrate pairs were established and the relative adsorption coefficients of the substrates were calculated from them. The effect of the substrate structure and the solvent effect on the hydrogenation rate and relative adsorptivity are discussed for the alkynic and dienic substances studied.

Sign in / Sign up

Export Citation Format

Share Document