ORG CHEM | Alkyl Halides

Alkyl Halides

also known as halo alkanes, they have one or more halogen atoms are bonded to an alkyl group; derivatives of alkanes where one or more hydrogen atoms are replaced with halogen atoms

Common Nomenclature of Alkyl Halides

alkyl group name + halogen with the suffix -ide

IUPAC Nomenclature of Alkyl Halides

1. Find the longest parent chain that has the halogen as a substituent

2. Number the parent chain just like you would a regular alkane. The halogen substituent has no priority so just ensure that the substituents have the lowest number possible.

3. Assemble the names in alphabetical order.

Primary Alkyl Halides (1º)

The carbon atom attached to the halogen is bonded to only one other carbon atom.

Secondary Alkyl Halides (2º)

The carbon atom attached to the halogen is bonded to two other carbon atoms.

Tertiary Alkyl Halide (3º)

The carbon atom attached to the halogen is bonded to three other carbon atoms.

Polarity of Alkyl Halides

It is highly polar due to the electronegativity difference between the carbon and halogen atom.

Boiling Point of Alkyl Halides

• They have higher boiling points than alkanes of similar molecular mass due to the presence of polar bonds and stronger dipole-dipole interactions.

• The boiling point increases with the size and the mass of the halogen as larger molecules have stronger dispersion forces (F < Cl < Br < I).

• The boiling point increases with the length of the carbon chain as larger molecules have stronger dispersion forces.

Solubility of Alkyl Halides

They are insoluble in water as the cannot form strong hydrogen bonds with the water molecules but they are soluble in nonpolar or weakly polar organic solvents.

Density of Alkyl Halides

Alkyl halides with chlorine, bromine, or iodine are denser than water due to the high atomic mass of halogens, while fluoroalkanes are usually less dense than water as fluorine atoms are lighter.

Uses of Alkyl Halides

solvents in chemical reactions like DCM, pharmaceuticals, pesticides, intermediates in the synthesis of alcohols.

Other Properties of Alkyl Halides