Difference between hexane and cyclohexane

Key difference - hexane vs cyclohexane

Hexane and cyclohexane are both alkanes with six carbon atoms each. However, the main difference between hexane and cyclohexane lies in their molecular structure. Hexane has a linear carbon chain while cyclohexane is a cyclic molecule. Due to the cyclic arrangement in its molecular structure, cyclohexane has a lower number of hydrogen atoms compared to hexane. Because of these structural differences, both hexane and cyclohexane have unique properties.

This article explores, 1. What is hexane - definition, molecular structure, properties, uses 2. What is cyclohexane - definition, molecular structure, properties, uses 3. What is the difference between hexane and cyclohexane? Difference Between Hexane and Cyclohexane - Comparative Summary

What is hexane?

The molecular formula of hexane, which consists of 6 carbon atoms and 14 hydrogen atoms, is C 6 H 14 . All bonds that connect carbons are single bonds. Therefore, hexane is an alkane and is unbranched. The molecular weight of hexane is 86.178 g / mol.

Hexane, also called n-hexane , is a colorless liquid that is often used as an organic solvent. It has a similar odor to petroleum. Hexane boils at 68.7 ° C and freezes at -95.3 ° C. In addition, it is highly flammable and has a relatively high vapor pressure, which makes it highly volatile.

Hexane is a non-polar solvent and does not mix with water. However, it is soluble in other organic solvents such as alcohol, ether, chloroform and acetone. This is often used in the extraction of vegetable oils. Since vegetable oils are non-polar, they dissolve easily in hexane. In addition, it is used as a cleaning and degreasing agent in various industries.

Difference between hexane and cyclohexane

Figure 1: Molecular structure of hexane

Hexane is part of the crude oil paraffin fraction and the natural gas that is separated off during crude oil refining at 65-70 ° C. It is released when polyvinyl chloride is burned. Human exposure is primarily due to skin contact or inhalation. Acute exposure can cause eye irritation, central nervous system depression, and symptoms such as nausea, headache, dizziness, and dizziness. Chronic exposure in extreme conditions can lead to polyneuropathy with numbness, muscle weakness, blurred vision, fatigue and headache. Hexane is not known to be carcinogenic.

What is cyclic cyclohexane?

Cyclohexane is, as the name suggests, a cyclic alkane. It does not contain multiple bonds. The molecular weight of cyclohexane is 84.162 g / mol. It has 2 fewer hydrogen atoms compared to hexane and the molecular formula is C 6 H 12 . The boiling point of cyclohexane is 80.74 ° C, while the freezing point is 6.55 ° C.

Like hexane, cyclohexane is a non-polar solvent and does not dissolve water. It is used as a solvent to dissolve substances such as fats, oils, waxes, lacquers, resins and cellulose ethers. Cyclohexane is widely used in perfume making, adipic acid making in nylon 66 making, paint and varnish industry, etc.

Key difference - hexane vs cyclohexane

Figure 2: Cyclohexane structure

Cyclohexane is a non-corrosive and flammable liquid. It is a mild irritant to the eyes, but inhalation of large amounts can cause damage to the central nervous system. This can lead to symptoms such as headache, anesthesia, and cramps. Cyclohexane is mainly released into the environment as a by-product of various industries. It is a helpful factor in the formation of photochemical smog.

Difference between hexane and cyclohexane

Molecular formula

Hexane: The molecular formula is   C 6 H 14

Cyclohexane: The empirical formula is   C 6 H 12

Molecular weight

Hexane: molecular weight is 86.178 g / mol

Cyclohexane: molecular weight is 84.162 g / mol

Freezing points

Hexane: freezing point is -95.3 ̊C

Cyclohexane: Freezing point is 6.55 ̊C

boiling point

Hexane: is boiling point   68.7 ° C

Cyclohexane: is boiling point   80.74 ° C

Intermolecular Attractions

Hexane: Hexane is comparatively less strong.

Cyclohexane: Cyclohexane is comparatively stronger.

Health risks

Hexane: Hexane is more dangerous.

Cyclohexane: Cyclohexane is less dangerous.


Hexane: Hexane is used as a cleaning solvent and degreaser.

Cyclohexane: Cyclohexane is used in the manufacture of paints, varnishes and nylon.


The main difference between hexane and cyclohexane lies in their structural arrangement. Hexane is linear while cyclohexane is cyclic. In addition, hexane has a slightly higher molecular weight than cyclohexane. This is because cyclohexane has 2 fewer hydrogens compared to hexane.

The volume that cyclohexane occupies is less than that of hexane due to its cyclic structure. Therefore, there is a higher number of cyclohexane molecules in a given molecule compared to hexane. The van der Waals forces between molecules are inversely proportional to the distance between the molecules. Because cyclohexane molecules are tightly packed, the molecular interactions are much stronger than those of hexane. Hence, the energy required to break the bonds and evaporate is much higher. Therefore, cyclohexane has a higher boiling point. There is also a large gap between their freezing points. Cyclohexane is easily condensed due to its stronger molecular interactions.

Hexane and cyclohexane have many similarities. They look the same to the eye and have a similar odor. Both are flammable. However, due to their structural difference, they have the different properties discussed above.

Reference: 1. “Hexane Solvent Properties.” Macromolecular Studies Group. Louisiana State University and Web. Feb. 15, 2017.2. "HEXANS." Scorecard home page. Np, nd web. Feb. 15, 2017. “3rd HEXANE | C6H14 - PubChem. “National Center for Biotechnology Information. US National Library of Medicine, nd Web. Feb. 15, 2017.4. “CYCLOHEXANES | C6H12 - PubChem. “National Center for Biotechnology Information. US National Library of Medicine, nd Web. 15th February 2017.

Image courtesy: 1. "Hexane Displayed" By Calvero. - Homemade with ChemDraw. (Public Domain) via Commons Wikimedia 2. “Cyclohexane for High School” By す じ に く シ チ ュ ー - Own work (CC0) via Commons Wikimedia

About the author: Pabasara

Pabasara has a bachelor's degree in chemistry and reads for M.Phil. in chemistry. She has work experience in both academic and industrial settings.