Organic Reactions - Hydrocarbons -

Flow Chart of Organic Reactions

Reactions of Alkanes Single covalent bonds between carbon atoms are relatively difficult to break, and thus alkanes are rather unreactive TWO Common Reactions of Alkanes Combustion Substitution

1) Combustion Reactions ∆ hydrocarbon + oxygen  carbon dioxide and water C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(g) NOTE: Assume COMPLETE combustion unless otherwise stated

Flow Chart of Organic Reactions

2) Substitution Reaction C-C bonds are difficult to break, H atom may be “substituted” by a halogen atom using F2, Cl2, and Br2 Reactions with F2 are fast, Cl2 and Br2 require heat or UV to dissociate the halogen molecule first Products  halogenated alkanes  called alkyl halides

Substitution reaction between ethane & bromine

As reactions proceeds, bromoethane concentration increases resulting in more substitution reactions

Reactions of Alkenes & Alkynes Due to double or triple bonds alkenes and alkynes are more reactive than alkanes Traditionally alkenes and alkynes undergo ADDITION reactions – where atoms are added to the molecule without losing hydrogen atoms

Reactions of Alkenes & Alkynes Four Common Addition Reactions Halogenation (with Br2 and Cl2) Hydrogenation (with H2) Hydrohalogenation (with hydrogen halides) Hyration (with H2O)

Flow Chart of Organic Reactions

Flow Chart of Organic Reactions

Flow Chart of Organic Reactions

Markovnikov’s Rule

“the rich get richer” Markovnikov’s Rule When a hydrogen halide or water is added to an alkene or alkyne, the hydrogen atom bonds to the carbon atom within the double bond that already has more hydrogen atoms. “the rich get richer”

Learning Checkpoint Assigned Questions: p. 27 Practice UC # 1, 2, 3

Reactions of Aromatic Hydrocarbons Generally, do NOT undergo addition reactions Less reactive than alkenes Aromatic hydrocarbons undergo substitution reactions (easier than alkanes) Reactivity of aromatic hydrocarbons between alkanes and alkenes

Learning Checkpoint Assigned Questions: p. 30 Practice UC # 4, 5, 6 p. 31 Section 1.3 UC # 2, 3, 4