Limonene

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Limonene
Limonene-3D-balls.png
Names
IUPAC name
1-Methyl-4-(1-methylethenyl)-cyclohexene
Other names
4-Isopropenyl-1-methylcyclohexene
Dipentene
DL-limonene
p-Menth-1,8-diene
Properties
C10H16
Molar mass 136.24 g/mol
Appearance Colorless or yellowish liquid
Odor Orange-like
Density 0.8411 g/cm3
Melting point −74.35 °C (−101.83 °F; 198.80 K)
Boiling point 176 °C (349 °F; 449 K)
0.0013 g/100 ml (20 °C)
0.00138 g/100 ml (25 °C)
Solubility Miscible in alcohol, benzene, carbon disulfide, carbon tetrachloride, chloroform, diethyl ether, oils
Immiscible with propylene glycol
Vapor pressure 1 mmHg (at 14 °C)
5 mmHg (at 40 °C)
10 mmHg (at 54 °C)
Thermochemistry
Hazards
Safety data sheet Sigma-Aldrich (D-Limonene)
Flash point 50 °C (122 °F; 323 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Limonene is a colourless liquid hydrocarbon, classified as a cyclic terpene. The D-isomer is the most common form encountered. The name comes from the lemon, as many citrus fruits and some evergreen plants contain high amounts of the D-isomer. It may be recognized as the smell of oranges, lemons, or other citrus fruits.

Properties

Chemical

Limonene is a relatively stable terpene and can be distilled without decomposition, although at elevated temperatures it cracks to form isoprene.

Physical

Limonene is a colorless liquid hydrocarbon. It has a strong smell of orange or lemon peels.

Availability

Limonene can be extracted from citrus fruit peels via steam distillation.

Pure limonene can also be bought online.

Preparation

The synthesis of limonene from basic hydrocarbons is complex, instead it's more efficient to extract it from citrus fruit juice.[1] It is often prepared in introductory organic chemistry classes by steam distilling an orange peel.

Projects

  • Extract various alkaloids from plants

Handling

Safety

Limonene and its oxidation products are skin and respiratory irritants, and limonene-1,2-oxide (formed by aerial oxidation) is a known skin sensitizer.

Storage

Should be stored under an inert gas, as it will slowly oxidize in contact with air.

Disposal

Limonene can be safely burned, however this produces lots of soot. Due to it's relative high flash point (50 °C) and to reduce soot, mix limonene with a more flammable solvent and then burn it. Best to do it outside.

References

  1. http://www.sciencemadness.org/scipics/Nicodem/Limonene.pdf

Relevant Sciencemadness threads