Description: Palladium on carbon (Pd/C) catalyzes the addition of hydrogen to C–C multiple bonds. For alkynes, this reaction will occur twice to give alkanes.
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if there are more than one multiple bonds in a structure, how do you know which one undergoes the reaction?
Depends on the type of multiple bonds. For alkenes, the order of reactivity is that the more alkyl groups are attached to the alkene, the more reactive it will be towards hydrogenation. If you have electron withdrawing groups attached to the alkene, they will also be less reactive towards hydrogenation. Essentially, the more electron-rich the alkene, the more reactive it will be towards hydrogenation. Thanks to commenter Daniel for correcting this error. See updated figure at the bottom of the page.
Just an FYI the middle of the page you have accidentially typed in mechanisms when it should state Examples .
You are doing an amazing job thank you so much for these references!
This is so wrong… see Smith, M. B. Organic Synthesis. 3 ed. pages 422-451. More accurately in page 432, where they say that more highly substituted alkenes do not adsorb on the catalyst as effectively and are not readily reduced. So, the more substituted olefin hydrogenated slower. And if you see in Handbook of Organopalladium chemistry, there are some instances displaying that unsaturated carbonyls hydrogenation sometimes is faster than ordinary olefins.
Thanks for correcting this error.
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