Nomenclature of Organic Halogen Compounds

Introduction

Any organic compound with at least one halogen (fluorine [F], chlorine [Cl], bromine [Br], or iodine [I]) bound to carbon is called an organohalogen compound. Alkyl, vinylic, aryl, & acyl halides are the four types of halides.

In alkyl halides, all 4 bonds to the halogen-carrying carbon are single bonds; in vinylic halides, the halogen-carrying carbon is doubly linked to another carbon.; the halogen-bearing carbon is a portion of an aromatic ring in aryl halides, and the halogen-bearing carbon is doubly bonded to oxygen in acyl halides.

Organohalogen compounds’ chemical reactivity varies greatly depending on the halogen, the class they belong to, including within a class. A halogen substituent is regarded as a functional group, and organohalogen compound reactions are essential in organic chemistry. Many organohalogen compounds, particularly organochlorine compounds, are essential industrial chemicals, serving as solvents, insecticides, and intermediates producing dyes, medicines, and synthetic polymers. Various plants, fungi, bacteria, and marine species have more than 2,000 organohalogen chemicals, naturally occurring molecules. Halogens can be introduced into organic molecules in a variety of methods, & organic halogen compounds can be reliably moved to different functional-group classes.

Nomenclature

• Halogen family

Fluorine, Chlorine, Bromine, Iodines are the members of the halogen family.

• Prefix Halo

Halo groups are always treated as substitutes. Halo (fluoro, chloro, bromo, iodo) is prefixed to word root to indicate the presence of a halogen.

Haloalkanes

Common name: Alkyl halide

IUPAC name : Haloalkane

Common name: Ethyl chloride

IUPAC name: Chloroethane

Haloarenes

Common name: aryl halide

IUPAC name: Haloarene

Bromobenzene

Nomenclature Of halogen derivatives of alcohols

Open chained hydroxy derivatives are called alcohols.

Common name: Alkyl alcohol

IUPAC name: Alkanol

Common name: Methyl alcohol Methyl alcohol

IUPAC name: Methan-1-ol

Nomenclature of Halogen Compounds

• Hydrogen halides are halogen-hydrogen binary compounds. Apart from HF, all are powerful hydrohalic acids once dissolved in water. These acids are toxic, and some of them are commonly used in chemical facilities.
• Metal halides are halogen and metal compounds. Highly ionic chemicals, monomeric covalent compounds, & polymeric covalent compounds all fall into this category. Metal halides can be made by directly combining an essential metal salt with a hydrohalic acid or neutralising it with hydrohalic acid.

When halogens react with one another, interhalogen compounds are created. In some ways, they resemble pure halogens, but their properties and behaviours are largely intermediates between the two parent halogens. However, some features are seen in neither parent halogen.

• Organic halides, often known as halogenated compounds, are organic compounds that include halogen atoms. Some halogens have many regulatory functions in the human body, while others aren’t. The nucleophilic abstraction reaction is used to make organohalogens.
• Polyhalogenated compounds are those that have many halogens replaced in them. Many of them are extremely hazardous to humans and bioaccumulate in their bodies, although they have a wide range of applications.

Every compound has two names: the chemical name and the other is the chemical name.

• Common name: It differs from a common name because it has a nomenclature that follows a set of rules.

• The IUPAC (International Union of Pure and Applied Chemistry) naming convention is the most often used nomenclature system among chemists.

Nomenclature Rules

• Locate the carbon chain that is the longest.
• The halogen is bonded to the carbon atom with the lowest number in the longest carbon chain.
• To indicate the number of identical halogen atoms linked to a carbon atom, multiple halogen atoms are labelled with Greek numerical prefixes such as di, tri, and tetra. The numeral is repeated many times if more than one halogen atom is linked to the same carbon atom.
• Different kinds of halogens are named alphabetically if they are attached.

• The halogen atom’s position is specified by placing the halogen’s position and name just before the parent hydrocarbon’s name.

Writing a Name: A Methodology

• Write the parent hydrocarbon’s root word first 
• Second, figure out how many halogen atoms are there. If more than one halogen atom is present, alphabetize the halogens in the prefix and identify them with their corresponding locations. If the same halogen atom appears many times, just use the prefix di, tri, tetra, and so on.

Haloalkane nomenclature of halogen derivatives

There are two ways to name alkyl halides. The alkyl group is designated first in the common system, followed by the appropriate phrase chloride, bromide, etc. An alkyl halide’s common name is always represented by two separate words. Alkyl halides are known as haloalkanes in the IUPAC system. The following are some of the additional rules that are followed while naming compounds:

• Choose the carbon atom chain with the most carbon atoms that contain the halogen atom.
• The carbon-carrying halogen atom should have the lowest number in the chain.
• When numerous bonds are present, the carbon chain prioritizes numbering.
• Any halogen derivative’s IUPAC name is always expressed as a single word.

Compound     Common Name                   IUPAC Name

CH3-Cl                    Methyl Chloride           Chloromethane

CH3-CH2-Br     Ethyl Bromide                     Bromoethane

CH3-C(CH3)2-Br    tert-Butyl bromide           2-Bromo-2-methylpropane

CHCl3               chloroform                     Trichloromethane

CH3-CH(Br)2     Ethylidene Bromide             1,1-Dibromoethane

CH2=CH-CH2-II       Allyl iodide                       3-Iodoprop-1-ene

Nomenclature of Haloarenes

Prefixing “halo” to the name of the source aromatic hydrocarbon gives rise to aryl halides.

If the ring has more than one substituent, mathematical numerals are used to indicate the relative positions of substituents.

The prefixes ortho, meta, and para indicate the relative location of two groups in the common system.

Some typical haloarenes are listed below and their common and IUPAC names.

Halogen Compounds Examples

1. 1. Name- bromoethane

    Class- primary alkyl halide

 2.Name- 2-chloropropane

    Class-   secondary alkyl halide

3. Name- fluorocyclopentane

    Class- secondary alkyl halide

4. Name- 2-iodo-2-methylpropane

     Class- tertiary alkyl halide

5. Name- 2,4-dibromopentane

    Class- two secondary alkyl halides

6. Name- 4-chlorotoluene

    Class- aryl halide

Conclusion:

At ordinary temperature and pressure, halogens have been the only periodic table class containing elements in three of the primary states of matter. When halogens are combined with hydrogen, acids are produced. Minerals or salt are used to make the bulk of halogens. Chlorine, bromine, and iodine, the middle halogens, are frequently disinfectants. The most common type of flame retardant is organobromine, but elemental halogens are hazardous and can be fatal.

In both industry and society, organohalogens are frequently employed. In rubber polymerization, chloromethane is employed as a solvent. Bromomethane is a standard fumigant, and the associated halons are more effective fire extinguishers than carbon dioxide.

Chlorine chemistry is used in 85% of all pharmacological agents and vitamins, and many medications need chlorine, fluorine, or bromine to be effective. Ear infections are treated with Ceclor and Lorabid, breast cancer is treated with Toremifene, and penicillin-resistant infections are treated with vancomycin, a natural antibiotic.