What is the Difference Between Open Chain and Closed Chain Hydrocarbons

Thekey difference between open chain and closed chain hydrocarbonsis that the open chain hydrocarbons are not cyclic structures, whereas the closed chain hydrocarbons arecyclic structures。

Hydrocarbon compounds areorganic compoundshavingcarbon和hydrogen atoms。最简单的碳氢化合物必须有一个carbon atom and one or more hydrogen atoms. Generally, we can see carbon-carbon bonds in hydrocarbon compounds.

内容

1.Overview and Key Difference
2.What are Open Chain Hydrocarbons
3.What are Closed Chain Hydrocarbons
4.Open Chain vs Closed Chain Hydrocarbons in Tabular Form
5.Summary – Open Chain vs Closed Chain Hydrocarbons

What are Open Chain Hydrocarbons?

Open chain hydrocarbons are organic compounds made of carbon and hydrogen atoms, and these compounds are acyclic (not cyclic compounds). Open chain hydrocarbons are mostly linear structures. There can be open chain hydrocarbons that have side chains. If there are no side chains attached to this type of hydrocarbon, we call it a straight-chain hydrocarbon. Typically, open chain hydrocarbons are aliphatic structures.

Generally, simple molecules in organic chemistry such as alkanes and alkenes have both linear and ring isomers. This means there are both cyclic and acyclic compounds. Often, cyclic compounds exist as芳烃。Hydrocarbons having more than four carbon atoms per molecule may or may not contain side chains. Therefore, these simple hydrocarbons may occur either in straight-chain form or branched-chain form. Moreover, when naming the open chain hydrocarbons, we use the prefix n- to describe the straight-chain isomer. We can use the prefix i- to name the iso-form of the compound, which is the branched structure of the open chain hydrocarbon.

Furthermore, not all the open chain hydrocarbon compounds are literally straight. This is because their bond angles are not always 180 degrees. But the name open chain or straight chain reflects that the compound is schematically straight. There can be wavy or puckered structures of open chain hydrocarbons.

What are Closed Chain Hydrocarbons?

封闭的链烃或环状烃是主要由碳和氢原子制成的环结构。在这些分子中，碳原子相互连接，形成了循环结构。此外，封闭的链碳氢化合物可以是芳香或非芳香化合物。

We can represent the structural formula of closed chain hydrocarbons in multiple ways. We can represent them with or without showing bond angles. The simplest closed chain hydrocarbons are cycloalkanes. Cycloalkanes have all carbon-carbon bonds as single bonds. They are saturated compounds as well. On the other hand, cycloalkenes are closed chain hydrocarbons with at least one C=C bond. Similarly, cycloalkynes are closed chain hydrocarbons with at least one carbon to carbon triple bond.

What is the Difference Between Open Chain and Closed Chain Hydrocarbons?

开放链和封闭链烃化合物是两种主要形式的碳氢化合物。开放链和封闭链碳氢化合物之间的关键区别在于，开放链烃不是循环结构，而封闭的链碳氢化合物是循环结构。此外，开放链碳氢化合物，主碳链中有末端官能团，而在封闭链碳氢化合物中，主碳链中没有末端官能团。同样，开放链和封闭链碳氢化合物之间的另一个区别是，开放式链碳氢化合物是非芳香的，但是封闭的链条碳氢化合物可以是芳香族或非芳香族。

The following table summarizes the difference between open chain and closed chain hydrocarbons.

Summary – Open Chain vs Closed Chain Hydrocarbons

A hydrocarbon compound essentially contains one or more carbon atoms and hydrogen atoms. Generally, well-known hydrocarbon compounds have carbon-carbon covalent bonds. The key difference between open chain and closed chain hydrocarbons is that open chain hydrocarbons are not cyclic structures, whereas closed chain hydrocarbons are cyclic structures.

Reference:

1.“”25.6：环状烃。”Chemistry LibreTexts, Libretexts, 2 June 2021.

Image Courtesy:

1.“”Cyclobutane-buckled-3D-balls”本·米尔斯（Ben Mills） - 通过Commons Wikimedia自己的作品（公共领域）
2. “六晶” Karlhahn的作品 - 通过Commons Wikimedia自己的作品（公共领域）