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Alkyl halides are probably one of the most commonly used compounds in the chemical industry.
They are formed by the replacement of hydrogen atoms with halogen atoms. These halogen atoms could include fluorine, chlorine, bromine, or even iodine.
Alkyl halides could also be manufactured from alkanes, alkenes, or alcohols. Also called haloalkanes and halogenoalkanes, alkyl halides are chemical compounds that are derived from alkanes. These alkanes contain at least one or more halogens.
When it comes to its applications, there are numerous alkyl halide uses ranging from their implementation in refrigerants to as basic as being used in fire extinguishers.
In this article, we will learn about the different alkyl halide uses and properties.
What are alkyl halides?
Alkyl halides are those compounds that have one or more hydrogen atoms in an alkane that are replaced with halogen atoms.
Depending on how the halogen atom is positioned, alkyl halides fall into different categories, which eventually cause chemical differences between them.
Classification of alkyl halides
Primary alkyl halides
Alkyl groups that have a carbon atom attached to them bonded with the halogen atom are known as primary alkyl halides.
Despite the complicated structure of the attached alkyl group, it doesn’t matter since there’s just one link to the alkyl group from the carbon group that holds the halogen.
A common alkyl halide example is CH3CH2Br.
Secondary alkyl halides
Similar to primary alkyl halides, the secondary alkyl halides have a carbon atom attached to two other alkyl groups bonded to the halogen atom.
The functional group in a secondary alkyl halide is attached to the secondary carbon atom.
A common example of a secondary alkyl halide is CH3CH(Cl)CH3, which is a secondary alkyl chloride because the functional group (CI atom) is attached to a secondary carbon atom. In such a case, the secondary carbon atom is the carbon that’s attached to the other two carbon atoms.
Tertiary alkyl halides
While primary and secondary alkyl halides have carbon atoms attached to one and two alkyl groups, respectively, tertiary alkyl halides have the carbon atom attached to three other alkyl groups.
This may produce any combination of the same or different alkyl groups that are bonded to the halogen atom.
A common example of a tertiary alkyl halide is 2 – Chloro-2-methylpropane.
Properties of alkyl halides
Alkyl halides are colourless in nature. They have properties that make them identifiable and distinct from other compounds.
Here are some of the most dominant properties of alkyl halides:
Odour – In their pure state, alkyl halides have a pleasant odour. However, all the higher alkyl halides don’t have any odour.
Boiling Point – alkyl halides have higher boiling points when compared to the corresponding alkanes. The reason for this is due to the polarity between haloalkanes and the strong dipole to dipole attraction between the molecules and a greater magnitude of van der Waals forces.
Solubility – Under a dipole moment of 2.05 to 2.15D, alkyl halides are polar in nature yet don’t form hydrogen bonds with water molecules. This makes them less soluble in water. However, alkyl halides have a higher solubility in organic solvents like ethers, benzene, and alcohols.
Colour – In their pure state, alkyl halides are colourless. However, when exposed to light for a longer period, bromides and iodides produce colour.
Density – Alkyl bromides and alkyl iodides are generally heavier than water. However, alkyl chlorides are lighter than water. The order of the density of alkyl halides in general is RI? RBr > RCI. Out of all the haloalkanes, methyl iodide is the heaviest.
Uses of alkyl halides
When it comes to alkyl halide uses, there are a variety of applications.
Right from domestic purposes to commercial purposes, there are many alkyl halides use examples, which we will mention in this section.
One of the most common alkyl halide use that is of importance is that they are used as solvents for non-polar compounds and the synthesis of a variety of organic compounds.
Alkyl halides are also used in cleansing agents and for creating cleaning formulas.
Haloalkanes are found in fire extinguishers.
Chloramphenicol, a chlorine-containing antibiotic, is an efficient treatment of typhoid fevers.
Alkyl halides are also used as paint removers.
The water-insoluble alkyl halides are often used as aqua-phobic solvents in chemical processes.
Alkyl halides are also used as refrigerants.
Conclusion
Judging by their significance, there are a variety of alkyl halide uses that make them applicable across different industries.
However, as useful as they are, alkyl halides also have serious health and environmental implications.
Over the years, their applications have also posed risks to different forms of life. This is why their use has been restricted.
Nevertheless, alkyl halides are still extremely useful in monitored environments, making them practically one of the most preferred compounds in the chemical industry.
