Citronella oil
[CAS# 8000-29-1]

Identification

• Classification: Food additive >> Food spice >> Natural spice additives
• Name: Citronella oil
• Synonyms: Cymbopogon nardus oil
• Molecular Formula: C₁₀H₁₈O
• Molecular Weight: 154.25
• CAS Registry Number: 8000-29-1
• EC Number: 616-771-7
• FEMA: 2308
• SMILES: CC(CCC=C(C)C)CC=O

Properties

• Density: 0.8±0.1 g/cm³, Calc.^*, 0.851 g/mL (20 °C) (Expl.)
• Index of Refraction: 1.437, Calc.^*, 1.451 (Expl.)
• Boiling Point: 208.4±9.0 °C (760 mmHg), Calc.^*, 207 °C (Expl.)
• Flash Point: 75.6±0.0 °C, Calc.^*, 75 °C (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02;GHS07;GHS08;GHS09 Danger
• Risk Statements: H315-H317-H318-H334-H335-H350-H411-H412
• Safety Statements: P203-P233-P260-P261-P264-P264+P265-P271-P272-P273-P280-P284-P302+P352-P304+P340-P305+P354+P338-P317-P318-P319-P321-P332+P317-P333+P317-P342+P316-P362+P364-P391-P403-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Serious eye damage	Eye Dam.	1	H318
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Respiratory sensitization	Resp. Sens.	1	H334
Skin sensitization	Skin Sens.	1	H317
Aspiration hazard	Asp. Tox.	1	H304
Carcinogenicity	Carc.	2	H351
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Reproductive toxicity	Repr.	2	H361
Acute toxicity	Acute Tox.	4	H302

Discovery and Applications

Citronella oil is an essential oil derived from the leaves and stems of plants in the *Cymbopogon* genus, primarily *Cymbopogon nardus* (Java citronella) and *Cymbopogon winterianus* (Sri Lankan citronella). The oil is typically extracted through steam distillation, yielding a pale yellow to brown liquid with a distinct, lemony aroma. Citronella oil has a long history of use in various cultures, particularly for its aromatic properties and its potential medicinal benefits.

The discovery of citronella oil can be traced back to Southeast Asia, where the plant has been used for centuries. It was originally used as a traditional medicine in regions where citronella is native, including in the treatment of fevers and other ailments. The oil was used in folk medicine, often applied to the skin to relieve pain and inflammation, and as a treatment for colds and digestive problems.

Citronella oil became widely known in the late 19th and early 20th centuries for its use as an insect repellent. It was found to be effective in repelling mosquitoes, flies, and other pests, leading to its inclusion in many insect-repellent products. This application of citronella oil has been extensively studied, and it is now recognized as one of the most common natural mosquito repellents. The oil’s effectiveness as a mosquito repellent is due to the compounds *citronellal* and *geraniol*, which are the primary active ingredients in the oil.

The oil is often used in personal care products, including insect-repellent sprays, candles, lotions, and oils, to protect against mosquitoes and other insects. Citronella oil has also been used in combination with other essential oils, such as eucalyptus or peppermint oil, to enhance its insect-repelling properties. In addition to its use as an insect repellent, citronella oil has been used in aromatherapy for its uplifting and refreshing scent. It is believed to have mild antidepressant and mood-lifting properties, and it is sometimes used to alleviate symptoms of stress and anxiety.

In addition to its use in personal care products, citronella oil has been employed in the food and beverage industry, where it is used as a flavoring agent and fragrance. It is recognized as a safe food additive and is used in small quantities to add a lemony flavor to various products. Citronella oil is also found in household cleaning products, where its fresh, clean scent is valued. It is sometimes used in natural cleaning formulations as a disinfectant, although its antimicrobial properties are considered less potent than those of other essential oils like tea tree or eucalyptus oil.

Citronella oil is also used in animal care products, particularly for pets. It has been used as a component in flea and tick repellents for animals, particularly dogs, although its use in pets should be monitored, as some animals may be sensitive to the oil. Citronella’s ability to repel insects and its mild fragrance make it a popular choice for products designed to protect both humans and animals from pests.

While citronella oil is generally considered safe when used appropriately, it should be noted that it can cause skin irritation or allergic reactions in some individuals. It is recommended to dilute citronella oil before applying it to the skin, and it should never be ingested in large amounts, as it can cause adverse effects such as nausea or vomiting. Citronella oil should also be used with caution around pets, as it can be toxic to animals in high concentrations.

In summary, citronella oil is a versatile essential oil with a long history of use for its insect-repellent properties. It is commonly used in personal care products, cleaning solutions, and insect-repellent formulations. Its applications in aromatherapy and as a flavoring agent further highlight its versatility. Despite its widespread use, caution should be taken to ensure safe application, particularly when used around pets or in concentrated forms.

References

2010. One-step microwave-assisted asymmetric cyclisation/hydrogenation of citronellal to menthols using supported nanoparticles on mesoporous materials. Organic & Biomolecular Chemistry, 8(12).
DOI: 10.1039/c003600e

2009. Cyclisation of citronellal over heterogeneous inorganic fluorides—highly chemo- and diastereoselective catalysts for (±)-isopulegol. Chemical Communications, (17).
DOI: 10.1039/b817572a

2009. Cyclization of citronellal to p-menthane-3,8-diols in water and carbon dioxide. Green Chemistry, 11(8).
DOI: 10.1039/b823297k