The hydrogenation of alkynes to alkanes occurs through an intermediate that is the alkene. It is possible to stop the hydrogenation in the alkene using a poisoned palladium catalyst, called Lindlar's catalyst.
The poisons decrease the activity of the catalyst and allow to stop the hydrogenation in the alkene.
![hydrogenation of alkynes with Lindlar hidrogenación de alquinos con Lindlar](/images/stories/organica-i/alkynes/hidrogenacion-lindlar/hidrogenacion-lindlar01.png)
![yo](/images/stories/yo.png)
![lindlar02 hydrogenation](/images/stories/organica-i/alkynes/hidrogenacion-lindlar/hidrogenacion-lindlar02.png)
[1] 2-Butyne
[2] cis-But-2-ene
[3] Undec-5-ine
[4] cis-Undec-5-ene