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Bulletin of the Chemical Society of Japan, 2006 , 65 (11) :2960-5. | Phenylacetaldehyde and Carbon Monoxide as Effective Additives for the Selective Hydrogenation of Cyclooctadienes to Cyclooctene over Palladium Catalysts[Reference: WebLink] | METHODS AND RESULTS: Three isomeric cyclooctadienes (1,5-, 1,4-, and 1,3-COD) were hydrogenated with Phenylacetaldehyde (PAA)- or carbon monoxide (CO)-treated palladium black in tetrahydrofuran at 25-degrees-C and atmospheric pressure of hydrogen. A complete depression of the hydrogenation of cyclooctene (COE) to cyclooctane (COA) was attained with both of the poisoned catalysts. By PAA the hydrogenation of 1,5-COD to COE was not hindered and the isomerization of 1,5-COD to 1,4-COD was greatly promoted, while the rate of hydrogenation of 1,4- and 1,3-COD decreased in the presence of PAA. By CO the hydrogenation and isomerization of 1,5-COD, as well as the hydrogenation of 1,4- and 1,3-COD, was suppressed. In the hydrogenation of 1,5-COD the PAA-treated palladium was more active and selective than was the CO-treated palladium for the formation of COE. CONCLUSIONS: The differences in the effects of these catalyst poisons are discussed on the basis of kinetic data concerning the individual and competitive hydrogenation of the three isomeric cyclooctadienes. |
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