Systematic nomenclature allows you to name representatives of different classes of organic compounds. Depending on belonging to a certain group of substances, there are certain nuances in the names that should be mentioned. Let's talk about how systematic nomenclature applies to hydrocarbons of various structures, as well as to oxygen-containing compounds.
Classification of organic compounds
According to the type of carbon chain, it is customary to subdivide organic substances into cyclic and acyclic; saturated and unsaturated, heterocyclic and carbocyclic. Acyclic substances are substances that do not have cycles in their structure. Carbon atoms in such compounds are arranged in series, forming straight or branched open chains.
Isolate saturated hydrocarbons that have single carbon bonds, as well as compounds with multiple (double, triple) bonds.
Alkanes nomenclature
Systematic nomenclature implies the use of a certain algorithm of actions. Compliance with the rules allows without errorsgive names to saturated hydrocarbons. If you need a task: “Name the proposed hydrocarbon according to the systematic nomenclature”, you must first make sure that it belongs to the class of alkanes. Next, you need to find the longest chain in the structure.
When numbering carbon atoms, the proximity of radicals to the beginning of the chain, their number, and also the name are taken into account. Systematic nomenclature involves the use of additional prefixes that specify the number of identical radicals. Their position is indicated by numbers, the quantity is determined, then the radicals are called. At the final stage, the long carbon chain is named by adding the suffix -an. For example, the hydrocarbon CH3-CH2-CH(CH)-CH2-CH3 according to the systematic nomenclature is called 3-methylpentane.
Alkene nomenclature
These substances according to the systematic nomenclature are called with the obligatory indication of the position of the multiple (double) bond. In organic chemistry, there is a certain algorithm of actions that helps to name alkenes. To begin with, in the proposed carbon chain, the longest fragment is determined, which includes a double bond. The numbering of carbons in the chain is carried out from the side where the multiple bond is located closer to the beginning. If the task is proposed: “Name the substances according to the systematic nomenclature”, you need to determine the presence of hydrocarbon radicals in the proposed structure.
If they are absent, name the chain itself, adding the suffix -en, indicating the position of the double bond with a number. Forrepresentatives of unsaturated alkenes, which contain radicals, it is necessary to indicate their position in numbers, add prefixes specifying the number, and only after that proceed to the name of the hydrocarbon chain itself.
As an example, let's name a compound of the following structure: CH2=CH-CH (CH3)-CH2-CH3. Given that the molecule has a double bond, a hydrocarbon radical, its name will be as follows: 3-methylpunten-1.
Diene hydrocarbons
The nomenclature of this class of unsaturated hydrocarbons is characterized by some peculiarities. The molecules of diene compounds are characterized by the presence of two double bonds, so the position of each of them is indicated in the name. Let's give an example of a connection belonging to this class, give its name.
CH2=CH-CH=CH2 (butadiene -1, 3).
If radicals (active particles) are present in the molecule, then their position is indicated by numbers, numbering the atoms in the main chain from the side that is closest to its beginning. If there are several hydrocarbon atoms in the molecule at once, the prefixes di-, tri-, tetra- are used when listing.
Conclusion
With the help of systematic nomenclature it is possible to name representatives of any classes of organic compounds. A general algorithm of actions has been developed that allows naming samples of saturated and unsaturated hydrocarbons. For carboxylic acids, which contain a carboxyl functional group, the numbering of the mainthe chain is carried out from it.
