Difference Between Hexane and n-Hexane

Main Difference – Hexane vs n-Hexane

Hexane and n-hexane are organic compounds which are included in the alkane category. They are saturated hydrocarbons and contain only single bonds between all atoms. Hexane and n-hexane are also aliphatic compounds. This means these are not ring structures. These compounds are important constituents of gasoline. Therefore, the main source of hexane compounds is gasoline. Since these are comparatively small hydrocarbons, they are easily evaporated. n-hexane is the linear form of hexane. Hexane is a mixture of branched and unbranched molecules having the chemical formula C₆H₁₄. The main difference between hexane and n-hexane is that hexane has 5 structural isomers that are either branched or unbranched whereas n-hexane is an unbranched structure.

Key Areas Covered

1. What is Hexane
      – Definition, Structure, Properties, and Reactions
2. What is n-Hexane
      – Definition, Structure, Properties, and Reactions
3. What are the Similarities Between Hexane and n-Hexane
      – Outline of Common Features
4. What is the Difference Between Hexane and n-Hexane
      – Comparison of Key Differences

Key Terms: Aliphatic, Alkane, Gasoline, Hexane, Hydrocarbon, N-Hexane, Paraffin Fraction, Structural Isomers

What is Hexane

Hexane is a hydrocarbon having the chemical formula C₆H₁₄. This chemical formula can occur in 5 major structural isomers. All these isomers are hexane compounds. The molar mass of hexane is 86.18 g/mol. It is a colorless liquid and has a strong odor.

Figure 1: 5 structural Isomers of Hexane

The above image shows the 5 structural isomers of hexane. Although their common names end with –hexane, the IUPAC names of these compounds are different from each other. The common names and IUPAC names for above molecules are given below.

Since these are different structures, these molecules have different melting points and boiling points. However, all these are colorless compounds. This is because they are small alkanes.

Hexane is comparatively less reactive. Therefore it acts as a good solvent for other compounds. As it is nonpolar, hexane compounds do not dissolve in water.

What is n-Hexane

n-hexane is an aliphatic hydrocarbon having the chemical formula C₆H₁₄. It is an alkane. Therefore, it is a colorless compound having a strong odor. The molar mass of n-hexane is about 86.18 g/mol. It is the linear or straight chain hydrocarbon form of hexane. It is a nonpolar compound. Therefore, it does not dissolve in water or in any other polar solvent. It can be used as a solvent for reactive compounds.

Figure 2: n-Hexane Structure

The IUPAC name for n-hexane is Hexane. The melting point of n-hexane is about -95^oC. The boiling point of n-hexane is given as 69^oC. Since the boiling point is a considerably high value, n-hexane is a liquid substance at standard temperature and pressure conditions.

n-hexane is considered as a highly volatile hydrocarbon. It can be found as a component in the paraffin fraction of crude oil refining. According to the NFPA (National Fire Protection Association), n-hexane is a slightly toxic highly flammable compound. n-hexane reacts vigorously with highly oxidizing agents such as liquid chlorine. It can be used as a cleaning agent in textile industry, printing, and in the manufacture of furniture.

Similarities Between Hexane and n-Hexane

• The chemical formula of both hexane and n-hexane is C₆H₁₄.
• Both compounds are liquids at room temperature and pressure.
• n-hexane is a structural isomer of hexane.
• Both are aliphatic hydrocarbons.
• The molar masses of the hexane compounds are equal to each other and to n-hexane.

Difference Between Hexane and n-Hexane

Definition

Hexane: Hexane is a hydrocarbon having the chemical formula C₆H₁₄.

n-Hexane: n-hexane is an aliphatic hydrocarbon having the chemical formula C₆H₁₄.

Structure

Hexane: Hexane compounds can be either branched or unbranched molecules.

n-Hexane: n-hexane is a unbranched molecule.

Isomers

Hexane: Hexane can be found in 5 main structural isomers.

n-Hexane: n-hexane has no isomers.

Boiling Point

Hexane: The boiling point of hexane molecules vary from one isomer to another.

n-Hexane: The boiling point of n-hexane is higher than that of other hexane compounds.

Conclusion

Hexane can be found in 5 main structural isomers. n-hexane is also a structural isomer of hexane. Therefore, both these compounds have the same chemical formula and the same molar mass. The main difference between hexane and n-hexane is that hexane has 5 structural isomers that are either branched or unbranched structures whereas n-hexane is an unbranched structure.

References:

1. “HEXANE.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here. Accessed 21 Aug. 2017.
2. “Toxic Substances Portal.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 3 Mar. 2011, Available here. Accessed 21 Aug. 2017.

Image Courtesy:

1. “Hexane isomers” By Steffen 962 – Own work, Public Domain) via Commons Wikimedia
2. “Hexane-2D-Skeletal” By Joel Holdsworth (Joelholdsworth) – Own work.(Public Domain) via Commons Wikimedia