Hydrogenation Reaction - Elmhurst College

Alkene Reactions Addition Reactions - only one product 1. Hydrogenation (H2): Alkene + Hydrogen --> Alkane 2. Halogenation (X2): Alkene + diatomic halogen --> Dihaloalkane 3. Halgenation (HX): Alkene + HX --> Haloalkane 4. Hydration (HOH): Alkene + HOH --> alcohol 5. Polymerization: Many alkenes add together into a long alkane chain Alkene Reactions 1. Hydrogenation Reaction Alkene + Hydrogen --> Alkane Hydrogen molecule adds to carbons with double bond. H3C

H C CH2 + H2 H3C H3C H C C H H

H H H2 C CH3 H H3C C H H C H

H Alkene Reactions Alkene Reactions 2. Halogenation Reaction Alkene + Halogen --> Dihaloalkane Halogen molecule adds to carbons with double bond. H3C H C Br CH2 +

CH CH2 Br2 H3C H3C H C C H Br Br Br H

H H3C C Br H C Br H Alkene Reactions Unsymmetrical Addition Reactions Markovnikovs Rule For double bonds that have unequal numbers of hydrogen atoms attached. For unsymmetrical reactants such as HX and HOH The hydrogen of the reactant goes to the carbon of

the double bond that already has the most hydrogen atoms. the rich get richer The -X or the -OH go the other carbon (the one with the least amount of hydrogen 3. Halogenation Reaction Alkene + HX --> haloalkane HCl molecule adds to carbons with double bond. H3C H3C H C CH2 CH CH3 + HCl

H3C Cl H C C H H Cl H Mark's Rule H H3C C

Cl H C H H Alkene Reactions 4. Hydration Reaction Alkene + HOH --> alcohol HOH molecule adds to carbons with double bond. H3C H3C H C CH2

+ CH CH3 HOH H3C H C HO C H H HO

H Mark's Rule H H3C C H C OH H H Alkene Reactions 5. Polymerization Reaction Alkene + Alkene + Alkene --> long chain of carbons

Double bonds convert to single bonds H H H H H H C C H C H C H C

C H H H H .C H C. H H H C H H

C H H C H H H C H H H .C C.

H C. H H H H C H H H .C C H C H2

H2 C C H2 H2 C C H2 H2 C Alkene Reactions What is the structure for Alkene Reactions

Alkene Reactions Alkene Reactions