Prab: CSV import

2025-03-03T17:49:20Z

CSV import

← Older revision		Revision as of 17:49, 3 March 2025
Line 50:		Line 50:

	{{Chemistry-stub}}		{{Chemistry-stub}}
			<gallery>
			File:Biadamantylidene-bromonium-ion-from-xtal-1994-2D-skeletal.png\|Biadamantylidene bromonium ion from xtal 1994 2D skeletal
			File:Halothane synthesis.png\|Halothane synthesis
			</gallery>

Prab: CSV import

2024-05-28T00:49:52Z

CSV import

New page

[[File:96._Адиција_на_хлор_на_етин.ogg|96. Адиција на хлор на етин.ogg|thumb]] '''Halogenation''' is a chemical reaction that involves the addition of one or more halogens to a compound. Halogens are a group of elements found in Group 17 of the [[periodic table]], which includes [[fluorine]], [[chlorine]], [[bromine]], [[iodine]], and [[astatine]]. Halogenation reactions are widely used in both organic and inorganic chemistry to modify the properties of molecules.

==Types of Halogenation==
Halogenation can be classified into several types based on the nature of the substrate and the halogen involved:

===Alkane Halogenation===
Alkane halogenation involves the substitution of a hydrogen atom in an [[alkane]] with a halogen atom. This reaction typically proceeds via a free radical mechanism and is commonly initiated by heat or light. For example, the chlorination of methane produces [[chloromethane]].

===Aromatic Halogenation===
Aromatic halogenation involves the substitution of a hydrogen atom in an [[aromatic compound]] with a halogen atom. This reaction usually requires a catalyst such as [[iron(III) chloride]] (FeCl3) for chlorination or [[aluminum bromide]] (AlBr3) for bromination. An example is the bromination of [[benzene]] to form [[bromobenzene]].

===Alkene and Alkyne Halogenation===
Alkenes and alkynes undergo addition reactions with halogens. In the case of alkenes, the halogen adds across the double bond, while in alkynes, the halogen adds across the triple bond. For example, the addition of bromine to ethene produces [[1,2-dibromoethane]].

==Mechanisms of Halogenation==
The mechanism of halogenation depends on the type of substrate and the conditions under which the reaction is carried out. Common mechanisms include:

===Free Radical Halogenation===
This mechanism involves the formation of free radicals and is typical for alkane halogenation. The reaction proceeds through initiation, propagation, and termination steps.

===Electrophilic Aromatic Substitution===
This mechanism is characteristic of aromatic halogenation. The halogen acts as an electrophile and substitutes a hydrogen atom on the aromatic ring.

===Electrophilic Addition===
This mechanism is observed in the halogenation of alkenes and alkynes. The halogen molecule adds across the multiple bond, forming a dihalide.

==Applications of Halogenation==
Halogenation reactions are important in various industrial and laboratory processes. Some applications include:

* The production of [[halogenated solvents]] such as [[chloroform]] and [[carbon tetrachloride]].
* The synthesis of [[pharmaceuticals]] and [[agrochemicals]].
* The modification of [[polymers]] to improve their properties.

==Safety and Environmental Concerns==
Halogenation reactions can produce hazardous by-products and require careful handling of reactive halogens. Environmental concerns include the formation of [[ozone-depleting substances]] and [[persistent organic pollutants]].

==Related Pages==
* [[Halogen]]
* [[Free radical]]
* [[Electrophilic aromatic substitution]]
* [[Alkane]]
* [[Alkene]]
* [[Alkyne]]
* [[Aromatic compound]]

==Categories==
[[Category:Chemical reactions]]
[[Category:Organic chemistry]]
[[Category:Inorganic chemistry]]

{{Chemistry-stub}}

Halogenation - Revision history

Prab: CSV import

Prab: CSV import