Another method of preparing alcohols is the reduction of aldehydes or ketones to alcohols. The simplest method is the hydrogenation of the carbon-oxygen double bond, using hydrogen in the presence of a platinum, palladium, nickel, or ruthenium catalyst.
![hydrogenation-carbonyls-01.png hidrogenacion-carbonilos-01.png](/images/stories/organica-i/alcoholes/sintesis-hidrogenacion-carbonilos/hidrogenacion-carbonilos-01.png)
Ethanal [1] is transformed by hydrogenation of the double bond into ethanol [2].
![hydrogenation-carbonyls hidrogenacion-carbonilos](/images/stories/organica-i/alcoholes/sintesis-hidrogenacion-carbonilos/hidrogenacion-carbonilos-02.png)
Cyclopentanone [1] is transformed by hydrogenation into cyclopentanol [2]