Haloalkanes

Haloalkanes

Haloalkanes are organic compounds in which one or more halogen atoms are covalently bonded to saturated carbon.

General formula is CnH2n+1X. X is a halogen atom (F,Cl,Br, or I)

Classification of haloalkanes

We classify a C atom as 1º, 2 º or 3 º according to the number of the C atoms attached to it.

Nomenclature of haloalkanes

Haloalkanes are named by adding prefix fluoro, chloro, bromo or iodo to the name of the corresponding alkanes.

Physical properties of haloalkanes

Haloalkanes have stronger intermolecules force compared to alkanes and alkenes.

Melting and Boiling Points

Name Formula Physical State Melting Point/°C Boiling Point/°C

Fluoromethane CH3F Gas -142 -78

Chloromethane CH3Cl Gas -97 -24

Bromomethane CH3Br Gas -94 4

Iodomethane CH3I Liquid -67 42

Chloroethane CH3CH2 Gas -136 12

Bromoethane CH3CH2Br Liquid -118 39

Iodoethane CH3CH2I Liquid -108 72

Straight chain isomers have high boiling point compared to branching chain isomers due to lower intramolecular force

Solubility in Water and Density

All the haloalkanes are insoluble in water but there are soluble in organic solvent. All haloalkanes expect bromoalkanes and iododalkanes are denser than water.

Reaction of haloalkane with ammonia

Will form amine RNH2 and NH3 in the nucleophile.Example, bromoethane (CH3CH2Br) react with NH3 and produce (CH3CH2NH2) ethanamine.

CH3CH2Br + 2NH3

Reaction of haloalkane with with Sodium Hydroxide (NaOH)

Will form alcohol and OHˉion is the nucleophile. Example, bromoethane (CH3CH2Br) react with aqueous NaOH and produce (CH3CH2OH) butanol

Reaction of haloalkane with Potassium Cyanide (KCN)

Produce alkanenitriles RCN and CNˉion, cyanide is the nucleophile. Example, bromoethane (CH3CH2Br react with KCN and produce (CH3CH2CN) propanenitrile

Nucleophilic Substitution of Haloalkanes

Halogen have greater electronegativity than carbon. The carbon...