You organic halides are compounds that have at least one halogen (elements of family 17 or 7A of the Periodic Table - F (fluorine), Cℓ (chlorine), Br, (bromine) or I (iodine)) directly attached to a carbon atom in a chain carbonic.
These organic compounds can be classified according to four criteria:
1. Dand according to the amount of halogens present in the molecule;
2. According to the type of halogen;
3. According to the type of carbon that is attached to the halogen;
4. According to the type of carbon chain.
See each case:
1. Dand according to the amount of halogens present in the molecule:
* Mono-halide: It has only one halogen atom in the molecule;
* Di-halide: It has two halogen atoms in the molecule;
* Tri-halide: It has three halogen atoms in the molecule, and so on.
2. According to the type of halogen;
* Fluoride: If the halogen attached to the organic radical is fluorine;
* Chloride: If the halogen attached to the organic radical is chlorine;
* Bromide: If the halogen attached to the organic radical is bromine;
* Iodide: If the halogen attached to the organic radical is iodine.
This classification is important because in the usual nomenclature of halides this classification is written, as shown in the following examples:
CH3 ─ CH Cl: chloride of ethyl
CH3 ─ CH ─ CH3: bromide of sec-propyl
│
br
CH3
│
CH3 ─ C ─ CH3: iodide of tert-butyl
│
I
3. According to the type of carbon that is attached to the halogen:
In the text carbon classification it is shown that if a carbon in the chain is bonded only to another carbon atom, it is classified as primary; if it is bonded to two other carbons, it is secondary; if it is bonded to three other carbons, it is tertiary; and if it's bonded to four other carbon atoms, it's quaternary.
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Based on this, the halide will also be classified as primary, secondary or tertiary, depending on the carbon that is directly attached to it. If carbon is primary, the organic halide will also be primary, and so on. However, there is no possibility of a quaternary halide, as one of the four carbon bonds is reserved for the halogen in question.
4. According to the type of carbon chain:
* Alcohol or alkyl halide: When halogen is bonded to a saturated carbon (which only has single bonds) and whose carbon chain can be cyclic or acyclic (open). This type of halide is usually represented by R − X, where "X" is the halogen and "R" is the alkyl radical;
* Aryl halide: When halogen is attached to a carbon belonging to a benzene ring. It is usually represented by Air− X.
This classification is considered the most important because it causes a big difference in reactivity.
See now some examples:
CH3 CH2 CH2 ─ I: monoiodide, primer and alkyl halide;
CH3 ─ CH ─ CH2 CH2 CH3: mono-bromide, secondary and alkyl halide;
│
br
CH3
│
CH3 ─ C ─ CH3: mono-chloride, tertiary and alkyl halide;
│
Cl
CH3 ─ CH ─ CH ─ CH3: - dibromide, secondary, alkyl halide;
│ │
br br
Cl
│
Cl─C─CH3: trichloride, primer and alkyl halide;
│
Cl
CH3
│
CH3 ─ C ─ CH3: monochloride, tertiary, alkyl halide;
│
Cl
mono-chloride, secondary, aryl halide.
By Jennifer Fogaça
Graduated in Chemistry
Would you like to reference this text in a school or academic work? Look:
FOGAÇA, Jennifer Rocha Vargas. "Classification of organic halides"; Brazil School. Available in: https://brasilescola.uol.com.br/quimica/classificacao-dos-haletos-organicos.htm. Accessed on June 27, 2021.
