Classification of Organic Compounds

There are many types of organic matter, which can be divided into two categories: hydrocarbons and hydrocarbon derivatives. According to the carbon frame structure of organic molecules, it can be divided into three types: open-chain compounds, carbocyclic compounds and heterocyclic compounds. According to the different functional groups contained in organic molecules, they are divided into alkanes, alkenes, alkynes, aromatic hydrocarbons and halogenated hydrocarbons, alcohols, phenols, ethers, aldehydes, ketones, carboxylic acids, esters and so on.

According to the carbon skeleton

(1) Chain compound

The carbon atoms in the molecules of this type of organic chemistry compounds are connected to each other in a chain shape. Because they were originally found in fat, they are also called aliphatic compounds. Its structural feature is that carbon and carbon are connected into an unclosed chain.

(2) Cyclic compounds

A cyclic compound refers to a compound in which the atoms in the molecule are arranged in a ring. Cyclic compounds are divided into alicyclic compounds and aromatic compounds.

(1) Alicyclic compounds: compounds with rings that do not contain aromatic rings (such as benzene rings, fused rings, or certain heterocyclic rings with benzene rings or fused ring properties). Such as cyclopropane, cyclohexene, cyclohexanol and so on.

(2) Aromatic compound: a compound with a ring containing an aromatic ring (such as a benzene ring, a condensed ring or some heterocyclic ring with benzene ring or condensed ring properties) such as benzene, benzene homologues and derivatives, fused ring aromatic hydrocarbons and derivatives, pyrrole, pyridine, etc.

By composition element

(1) Hydrocarbon. Organic substances that only contain two elements, carbon and hydrogen, are called hydrocarbons, or hydrocarbons for short: such as methane, ethylene, acetylene, benzene, etc. Methane is the simplest hydrocarbon.

(2) Hydrocarbon derivatives. A series of compounds in which the hydrogen atoms in hydrocarbon molecules are replaced by other atoms or groups of atoms are called hydrocarbon derivatives: such as halogenated hydrocarbons, alcohols, amino acids, nucleic acids, etc.

By functional group

(1) Functional group: The atom or group of atoms that determines the special properties of a compound is called a functional group or functional group. The chemical properties of compounds containing the same functional group are basically the same. Common functional groups are carbon-carbon double bonds, carbon-carbon triple bonds, hydroxyl groups, carboxyl groups, ether bonds, aldehyde groups, carbonyl groups, etc.

(2) Homologs: Organic substances with similar structures and different molecular composition by one or several "CH₂" atomic groups are called homologs, and must be the same type of substance (containing the same and equal number of functional groups, except for the hydroxyl group, phenol and alcohol cannot be homologous, such as phenol and benzyl alcohol). Due to the similar structure, the chemical properties of the homologues are similar; their physical properties often change regularly with the increase of molecular weight.