Alkene Reactions

1. Hydrogenation – Addition by hydrogen. Alkanes are formed when the H2 adds to the alkene molecule. A catalyst of nickel or platinum is used at a temperature of about 150 °C g.

CH2 = CH2 + H2 -> CH3CH3

2. Halogenation – Addition of bromine or other halogens. Halogen alkenes are formed when halogens attach to the carbons in the double bond by covalent bonds g.

CH2 = CH2 + Br2 -> CH2BrCH2Br

3. Hydration – Addition of water. Alcohols form when water is added to alkene molecules. A catalyst of dilute H2SO4 or H3PO4 is

CH2 = CH2  + H2O -> CH3–CH2–OH