A usually desired consecutive reaction is the hydrogenation of the aldehydes to alcohols. Higher temperatures and hydrogen partial pressures favor the hydrogenation of the resulting aldehyde to the alcohol. For the reaction mechanism it is believed that the aldehyde initially forms a CO-π-complex with the catalyst. This is rearranged to the alkoxide complex and by subsequent oxidative addition of hydrogen the alcohol is eliminated and the starting complex is formed.
The aldehydic carbon-oxygen double bond can also be subject to hydroformylation, which leads to formic acid and its esters. The reaction requires the carbon monoxide insertion into the oxygen-metal bond of the alkoxide complex. The resulting formyl complex can converted into the formic acid esters and the starting complex by oxidative addition of hydrogen. The initially produced aldehydes can react further by aldol condensation to either target product precursors like 2-ethylhexenal or higher molecular weight condensation products, so-called thick oil.