Question

What is hydrogenation of alkenes?

Answer 1

Hydrogenation of an alkene is the addition of H₂ to the C=C double bond of the alkene.

The C=C double consists of a σ bond and a π bond. The π bond is relatively weak, so it can be easily broken.

However, the addition of H₂ has a high activation energy. The reaction will not proceed without a metal catalyst, such as Ni, Pt, or Pd.

The two H atoms add to the same face of the double bond, so the addition is syn. The product is an alkane.

Hydrogenation is used in the food industry to convert liquid oils into saturated fats.

This process yields semi-solid products like shortening and margarine.

Here's a video on the catalytic hydrogenation of alkenes.