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What is Hexane?

Hexane is an organic compound, a straight-chain alkane with six carbon atoms with the molecular formula C6H14. It is an odourless and colourless liquid, when pure, and it has a boiling point of approximately 69 °C (156 °F). It can be used widely as a relatively safe, largely unreactive, cheap, and easily evaporated non-polar solvent.

Hexane is a significant gasoline constituent. At times, it refers to a mixture, which is composed largely (> 60%) of hexane, with differential amounts of the isomeric compounds: 2-methyl pentane, 3-methyl pentane, and, possibly, the smaller amounts of non-isomeric C5, C6, C7 alkanes (cyclo). Hexane is one of the cheaper compounds and is often used in large-scale operations without requiring a single isomer (a cleaning solvent or for chromatography, as an example).

The other names of hexane can be given as 1-Hexanol, Amyl Carbinol, 1-Hydroxyhexane, and Hexyl alcohol.


Properties of Hexane

The physical properties of Hexane - C6H14 are as follows.

Physical Properties of Hexane

Appearance

Colourless volatile liquid

Odour

Gasoline-like odour

Vapour Pressure

17.60 kPa (at 20.0 °C)

Complexity

12

Viscosity

3.26 10-4 Pa-s at 20℃

Solubility

9.5 mg L−1


The chemical properties of Hexane - C6H14 are as follows.

Chemical Properties of Hexane - CH₁₄

IUPAC Name

Hexane

Molecular Weight or Molar Mass

86.18 g/mol

Density

655 kg/m³

Boiling Point

68.5 to 69.1 °C

Melting Point

−96 to −94 °C

Chemical Formula

CH3(CH2)4CH3


  • Hexane compound undergoes combustion reaction readily to produce water and carbon dioxide molecules. The chemical reaction is given below.

2C6H14 + 19O2 → 12CO2 + 14H2O

  • Hexane, being as the higher hydrocarbons, undergo thermal cracking produces more than one hydrocarbon.

C6H14 (by thermal cracking) → C4H10 (called butane) + C2H4 (called ethene)


Hexane Structure - CH₁₄

The structure of Hexane can be represented as follows.

(Image to be added soon)


Production of Hexane

Hexanes are obtained chiefly by crude oil refining. This fraction's exact composition largely depends on the oil source (reformed or crude) and the refining constraints. The industrial product (in general, around 50% by straight-chain isomer weight) is given as the fraction boiling at 65-70 °C (149-158 °F).


Use of Hexane

Industrially, hexanes can be used in the formulation of glues for shoes, roofing, and leather products. They can also be used to extract cooking oils (like soy oil or canola oil) from seeds, for degreasing and cleaning a variety of items, and in the manufacturing of textiles. Commonly, in the United States, they are used in the food-based soybean oil extraction, and also they are potentially present as contaminants in all those soy food products where the technique can be used; the lack of regulation by the FDA (Food and Drug Administration, the USA) of this contaminant is some controversy matter.

One of the typical laboratory hexanes uses is to extract grease and oil contaminants from water and soil for analysis. Since the hexane solvent or hexane compound cannot be easily deprotonated, it can be used in the laboratory for reactions, involving the stronger bases, like the organolithiums preparation. As an example, typically, butyllithiums are supplied as a hexane solution.

In general, hexanes are used as a non-polar solvent in chromatography. Higher alkanes exist as impurities in hexanes contain the same retention times as that of solvent, which means that the fractions containing hexane also contain these impurities. In the case of preparative chromatography, the large volume of hexane concentration can result in a sample, which is appreciably contaminated by alkanes. This can result in a solid compound being obtained as an oil, and the alkanes may interfere with the analysis.


Hexane Safety

Hexane's acute toxicity is rather low. Inhaling n-hexane or hexane n at 5000 ppm for just 10 minutes produces marked vertigo. If it is 2500-1000 ppm for 12 hours, it can produce fatigue, appetite loss, drowsiness, paresthesia in the distal extremities. If 2500–5000 ppm, it can produce cold pulsation in the extremities, muscle weakness, headache, anorexia, and blurred vision.

Chronic occupational exposure to the elevated levels of n-hexane or hexane n has been described to be associated with neurotoxicity in workers in printing presses, peripheral neuropathy in auto mechanics in the United States, furniture and shoe factories in Europe, Asia, and North America.

At times, n-Hexane is allowed for various usages like, as a denaturant for alcohol, cleaning agents in the textile, furniture, and leather industries.

Similar to gasoline, hexane is also highly volatile, and it is an explosion risk.


Intermolecular Forces of Hexane

Hexane is a non-polar molecule because of 2 factors. Firstly, it has the only bond as C-H, which is non-polar due to hydrogen and carbon having many similar electronegativities. Secondly, hexane is symmetric, and hence, any polarity in the molecule would eliminate out. Thus, the only intermolecular force acts in hexane are the van der Waals forces/London Dispersion forces or the induced dipole-dipole forces.

Where these are caused by the electrons present in hexane repelling electrons in neighboring hexane molecules, hence inducing a small positive dipole or charge, which then interacts with electron-dense areas in the original molecule.


Did You Know?

  • Hexane is a strong solvent when we are trying to dissolve a non-polar compound. However, if we try to use a hexane solvent to dissolve a polar compound, it would be highly unsuccessful. Water would be a safer option than hexane with a polar compound because water is polar, and it can interact more readily with any polar compound.

FAQ (Frequently Asked Questions)

1. What are hexanes used for?

Hexanes can be used for the manufacture of leather goods, roofing glues, and clothing. They can also be used to extract cooking oils from seeds (like soy or canola oil), clean and degrease a wide variety of products, and manufacture textiles.

2. Why is hexane said flammable?

N-Hexane or hexane n is a compound which -produces crude oil. At the same time, a pure n-Hexane is a liquid with an unpleasant odor slightly. In its vapors, it is extremely flammable and can be explosive. The key application for the solvents containing n-Hexane is to extract vegetable oils from crops like soybeans.

3. Why is hexane used for the extraction process?

N-hexane can be used as a solvent in the solvent extraction process for its attributes like non-polar existence, quick recovery, low vaporizing latent heat (at 330 kJ / kg), and also the high solvent selectivity. Also, enzyme processing contains the significant potential to extract oil in the oilseed industry.

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