1. Haloalkanes
…workbook pgs …

2. Haloalkanes
Compound where a halogen (Group 17) replaces one of the hydrogens on a carbon
Prepared by substitution reaction of an alkane with a halogen, or by addition reaction of an alkene with HX
General Formula:
R- X
CnH2n+1X
`Example:
CH3CH(Br)CH2CH2CH3
2-bromopentane

3. Haloalkane Nomenclature
If a Hydrogen is replaced by a halogen, this information is added in the prefix
Flourine = “Fluoro-”
Chlorine = “chloro-”
Bromine = “bromo-”
Iodine = “Iodo-”
Like alkenes and alkynes, the longest continuous chain must contain the halide.
Also, count the carbons so that the halide has the lowest number possible

4. Types of Haloalkanes Just like with alcohols: 3 Types
Primary Haloalkane
Haloalkane with only 1 “R” group….
Secondary Haloalkane
Haloalkanel with 2 “R” groups…
Tertiary Haloalkane
Haloalkane with 3“R” groups…

5. Types of Haloalkanes

6. Types of Haloalkanes

7. Properties of Haloalkanes
Halide group (except for fluorine) are slightly polar and allows for slightly polar molecules
IMF due to temporary dipoles and permanent dipole interactions
Haloalkanes have high melting and boiling points than corresponding alkanes
Melting and boiling points increase as mass increases
Chloromethane, bromomethane, and chloroethane are gases; most other haloalkanes up to 6 carbons are liquids; larger ones are solids
Haloalkanes are slightly soluble in water b/c hydrogen bonding can’t occur

8. Reactions of Haloalkanes
Substitution Reactions
Nucleophilic substitution – when a nucleophile (negative ion, like OH-, or group with a lone pair of electrons) is attracted to the partially positive carbon atom nearest the halogen atom
With Ammonia (NH3)
Will form amines

9. Reactions of Haloalkanes
Substitution Reactions
Reaction with aqueous hydroxide ion
Forms alcohols

10. Reaction of Haloalkanes
Elimination Reaction of Haloalkanes
A molecule of HX is removed and an alkene is formed
Under non-aqueous strongly basic conditions
Opposite of Markovnikov’s rule – H comes off the carbon with the fewest number of H’s attached
Primary Haloalkanes very difficult to undergo elimination. Secondary Haloalkanes react faster, Tiertiary the fastest