Effects of Ir content on selective hydrogenation of crotonaldehyde over Ir/ZrO2 catalysts

A series of Ir/ZrO2 catalysts with different Ir contents were tested for gas phase selective hydrogenation of crotonaldehyde. It was found that the reactivity of the catalyst increased with increasing Ir content, but rapid deactivation was observed on all the catalysts during the reaction, which might be due to CO poisoning generated by decarbonylation reaction. The highest selectivity (82.2%) to crotyl alcohol was obtained over a catalyst with 3% Ir content, which was attributed to the proper Ir particle size and the highest amount of surface acid sites in the catalyst.

The carbonyl oxygen of crotonaldehyde is suggested to strongly interact with Lewis acid sites (σ2) and the Ir particle is the adsorption center of CC band (π) and carbonyl carbon (σ1).Figure optionsDownload as PowerPoint slideHighlights
► Ir/ZrO2 catalysts were used for selective hydrogenation of crotonaldehyde.
► 3% Ir catalyst has the highest selectivity (82.2%) to crotyl alcohol.
► The deactivation is due to CO molecules produced during the reaction.