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.

Catalytic hydrogenation of binary and ternary mixtures of unsaturated substances in the liquid phase on platinum

1979 ◽  
Vol 44 (8) ◽  
pp. 2378-2383 ◽  
Author(s):  
Libor Červený ◽  
Radka Junová ◽  
Vlastimil Růžička
Keyword(s):  
Liquid Phase ◽  
Binary Mixtures ◽  
Silica Gel ◽  
Catalytic Hydrogenation ◽  
Ternary Systems ◽  
Ternary Mixtures ◽  
Unsaturated Alcohol ◽  
Solvent Concentration ◽  
Binary And Ternary Mixtures ◽  
Hydrogenation Selectivity

Hydrogenation of olefinic substrates in binary and ternary mixtures using 5% Pt on silica gel as the catalyst was studied in normal conditions in the liquid phase with methanol or cyclohexane or in solvent-free systems. The effect of the solvent concentration on the selectivity of hydrogenation of the unsaturated alcohol-olefin binary mixtures was investigated. In ternary systems of unsaturated substrates, the effect of each of the substrates on the selectivity of hydrogenation of the remaining two substances was examined. Another system was found in which a jump change of the hydrogenation selectivity occurred on the vanishing of the fastest reacting substance.

Infrared Quantitative Analysis of Mixtures Containing Isopropenyl Stearate, Stearic Acid, Stearic Anhydride, and Mixed Stearic—Acetic Anhydride

1972 ◽  
Vol 26 (1) ◽  
pp. 96-99 ◽  
Author(s):  
Mary Jo Calhoun ◽  
Edward S. DellaMonica
Keyword(s):  
Acetic Anhydride ◽  
Stearic Acid ◽  
Relative Concentration ◽  
Ternary Systems ◽  
Spectral Interference ◽  
Complex Mixtures ◽  
Ratio Method ◽  
Baseline Method ◽  
Binary And Ternary Systems

A method for the determination of individual components of complex mixtures is presented. The technique used is based on ir-absorbance measurements for stearic acid at 1700 and at 935 cm−1 when the concentration range exceeds 0.50% wt/vol; for isopropenyl stearate at 1145 and at 865 cm−1; for stearic anhydride at 1030 cm−1 and mixed stearic-acetic anhydride at 1000 cm−1. The baseline method was used in all absorbance measurements. Absorbance-concentration relationships obeyed Beer's law from 0 to 2.0% wt/vol for most compounds; the exception being stearic acid (at 1700 cm−1), where linearity was limited to a maximum 0.50% wt/vol. Due to spectral interference between the two anhydrides at low concentration ratios, an empirical percent transmission ratio method was used to estimate the relative concentration of each. Binary and ternary systems were studied and the standard deviations of the differences between theoretical and calculated values indicate that this method is reliable.

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