Addition Reactions (continued)

This addition reaction is also called alkene hydration. It occurs similarly to the HX addition reaction.

It is an acid catalyzed reaction and also follows Markovnikov's rule. Hydrogen enters the most hydrogenated carbon and hydroxyl into the less hydrogenated carbon.

Form as product, primary and secondary alcohol. Example:

Aromatics undergo substitution reactions, but in some cases an addition occurs. When there is total hydrogenation of the benzene ring, the reaction is an addition.

This reaction is not so easy to do. Here's the example of hydrogen being added to benzene to form a cyclic hydrocarbon, cyclohexene:

+ 3H2   →    

This reaction is only possible if the nickel (Ni) or platinum (Pt) metal catalyst is used at a temperature of 300 ° C and a pressure of 200atm.