Hydrocarbons–Functional Group and Its Nomenclature

The chemistry of carbon and its compounds is a fascinating subject to research. When comparing diamond with charcoal, one is a beautiful, gleaming hard rock, while the other is a mushy, ashy substance. However, both are carbon! The differences in their properties are due to the various configurations of carbon atoms. This study of hydrocarbons, its functional group, and its nomenclature reveals information on the chemical characteristics of other functional groups.

Hydrocarbons

Hydrocarbons are organic molecules composed entirely of two types of atoms: carbon and hydrogen. Hydrocarbons are typically colourless gases with relatively mild odours. Hydrocarbons are divided into alkynes, alkanes, alkenes, and aromatic hydrocarbons. The functional groups’ table also explains that all four subcategories have simple or moderately complex structures.

In addition, liquefied petroleum gas (LPG) is made from hydrocarbons like propane and butane and is utilised as a commercial fuel (LPG). Benzene, one of the most basic aromatic hydrocarbons, is used as a starting ingredient for several synthetic medications.

Saturated and unsaturated hydrocarbons

• Saturated hydrocarbons have single bonds (carbon-carbon).

• Unsaturated is a term that refers to the process where more hydrogen atoms are added to hydrocarbons in order to make it saturated. Unsaturated hydrocarbons have double and triple bonds (carbon-carbon). 

Role of hydrocarbons in functional groups and its nomenclature

The empirical formula of hydrocarbons differs owing to their various molecular configurations. Alkanes, alkynes, and alkenes, for example, have less bound hydrogen than alkanes, alkynes, and alkenes. This is because of carbon’s “self-bonding” or catenation, which prevents the hydrocarbon from becoming completely saturated by forming double or triple bonds. Catenation is the capacity of hydrocarbons to form bonds with one another. Thanks to their abilities, they can produce more complicated compounds like cyclohexane and, in rare cases, aromatic hydrocarbons like benzene.

On the contrary, the cracking of hydrocarbons breaks down heavy organic molecules into lighter molecules. This is performed by providing sufficient heat and pressure. Catalysts are sometimes employed to speed up reactions. This procedure is extremely significant in the commercial manufacturing of diesel fuel and gasoline.

Carbon’s catenation property

Carbon compounds surround everything in organic chemistry. One of the most important parts of any living body, carbon, is made up of two stable isotopes: 12-C and 13-C. After these two, there is one more carbon isotope, 14-C. Carbon is a radioisotope with a half-life of 5770 years that is used for radiocarbon dating.

Four hydrocarbon functional groups

The four hydrocarbon functional groups are:

1. Alkanes
2. Alkenes
3. Alkynes
4. Arenes

Alkanes

They are single-bonded carbon and hydrogen atoms. The general formula for alkanes is CnH2n+2. 

Alkanes are further divided into three groups: 

1. Linear straight-chain alkanes
2. Branched alkanes
3. Cycloalkanes

Alkenes and alkynes

Alkenes comprise at least one carbon-carbon double bond with the general formula CnH2n and have one carbon-carbon triple bond with the general formula CnH2n-2.

Arenes

Arenes, also known as aromatic hydrocarbons, have at least one aromatic ring. 

Nomenclature of aliphatic compounds

According to the IUPAC system, the name of an organic compound is made up of the following parts.

1. Word root 
2. Primary suffix
3. Secondary suffix 
4. Prefix

The number of carbon atoms in the parent chain is represented by the word root. Special word roots are used for chains with up to four carbon atoms, whereas Greek numerals are used for chains with more than four carbon atoms.

Nomenclature of compounds with a single functional group

The presence of functional groups in the molecule except (C = C or C) is indicated by secondary suffixes. However, some functional groups are taken as substituents denoted by prefixes. There are different rules that must be followed in writing the names of compounds with only one functional group. They are:

Rule 1: The longest chain wins

As the parent chain, choose the carbon atoms’ longest continuous chain. The carbon atoms involved in COOH, CHO, CN, and those carrying functional groups like OH, NH2, Cl, NO2, and others must be included in the chosen chain. The word root is determined by the number of carbon atoms in the parent chain.

Rule 2: The rule of the lowest number

The parent chain’s carbon atoms are numbered in a way that the functional group’s carbon atom receives the lowest possible number. If the functional group lacks a carbon atom, the parent chain’s carbon atom connected to the functional group must receive the lowest number.

Rule 3, 4, and 5 are applied in the same way as hydrocarbons.

Compounds with many functional groups that are similar in name

If an organic molecule has more than one comparable functional group, the numerical prefixes like di (2), tri (3), and so on are appended before the secondary suffix that specifies the functional group, in addition to different regulations. The basic suffix’s vowel ‘e’ is kept when such words are added.

Rules for writing names

There are several rules for writing names. Let us break down the many laws of nomenclature into components in order to gain a better knowledge of them.

• Hydrocarbon nomenclature

• Compounds with only one functional group are called monofunctional compounds

• Nomenclature for compounds with many functional groups that are comparable

• Compounds containing more than one dissimilar functional group are referred to by their nomenclature

Conclusion

All the normal (straight-chain) hydrocarbons, in which straight chains of hydrocarbons are joined by single bonds and the valences of the carbons are saturated with hydrogens, are useful to know. These compounds’ names are the starting points for other compounds with the same number of carbon atoms in a continuous chain. A substituent group is formed when the end hydrogen in one of these chains is replaced with another atom.