Halogenated hydrocarbon

Hydrocarbons that contain some hydrogen of the molecule substituted by some atom from the halogen group (fluorine, chlorine, bromine or iodine). Within this classification are included both aliphatic or aromatic hydrocarbons, such as benzene and its derivatives.

Generally, these compounds are obtained from the corresponding alkanes, through reactions such as electrophilic aromatic substitution in the case of aromatic hydrocarbons and radical halogenation reactions in the case of aliphatic hydrocarbons. Regarding the ease of synthesis, fluoroalkanes are synthesized radically in a very exothermic, almost explosive way, with reactivity decreasing as we go down the group (chlorine, bromine and iodine) until reaching iodine where the reaction is endothermic. The best halogenations are made with chlorine and bromine.

Chemically, the halogenation of an alkane results in a decrease in the reactivity of the molecule by forming a more stable bond than in the case of C-H and which also prevents the oxidation of carbon (we have the extreme example of CFCs's, which are very stable against oxygen and other reagents that would usually react with alkanes).

Physically, the addition of very electronegative atoms and heavier than hydrogen to an alkane causes an increase in molecular mass and an increase in Van der Waals forces between molecules, which has the consequence that these compounds appear as liquids before their hydrogenated counterparts. This has been used in chlorofluorocarbons in refrigeration systems, due to its chemical stability and its high enthalpies of vaporization.etc

Some examples of them are the following: CH3-CH2-CH2-Cl 1-chloropropane