alpha-Terpinene
[CAS# 99-86-5]

Identification

• Classification: Organic raw materials >> Hydrocarbon compounds and their derivatives >> Cyclic hydrocarbon
• Name: alpha-Terpinene
• Synonyms: 1-methyl-4-propan-2-ylcyclohexa-1,3-diene
• Molecular Formula: C₁₀H₁₆
• Molecular Weight: 136.23
• CAS Registry Number: 99-86-5
• EC Number: 202-795-1
• FEMA: 3558
• SMILES: CC1=CC=C(CC1)C(C)C

Properties

• Density: 0.8±0.1 g/cm³, Calc.^*, 0.837 g/mL
• Index of Refraction: 1.476, Calc.^*, 1.478
• Boiling Point: 174.1±0.0 °C (760 mmHg), Calc.^*, 173-175 °C
• Flash Point: 46.1±0.0 °C, Calc.^*, 50 °C

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

Safety Data

• Hazard Symbols: GHS02;GHS07;GHS08;GHS09 Danger
• Risk Statements: H226-H302-H304-H317-H319-H411
• Safety Statements: P210-P233-P240-P241-P242-P243-P261-P264-P264+P265-P270-P272-P273-P280-P301+P316-P301+P317-P302+P352-P303+P361+P353-P305+P351+P338-P321-P330-P331-P333+P317-P337+P317-P362+P364-P370+P378-P391-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Flammable liquids	Flam. Liq.	3	H226
Acute toxicity	Acute Tox.	4	H302
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Aspiration hazard	Asp. Tox.	1	H304
Eye irritation	Eye Irrit.	2	H319
Skin sensitization	Skin Sens.	1	H317
Skin sensitization	Skin Sens.	1B	H317
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H332
Reproductive toxicity	Repr.	2	H361
Eye irritation	Eye Irrit.	2A	H319
Serious eye damage	Eye Dam.	1	H318

Discovery and Applications

Alpha-terpinene is a natural monoterpene and an important component of essential oils derived from various plants, including thyme, cumin, and tea tree. This compound is characterized by its pleasant aroma and is classified as a colorless to pale yellow liquid. The discovery of alpha-terpinene dates back to the 19th century when it was first isolated from the oil of the herb thyme. Its chemical structure, C10H16, features a bicyclic structure with a characteristic terpene backbone, which contributes to its various applications.

The interest in alpha-terpinene has grown significantly due to its potential health benefits and versatile uses in different industries. One of its primary applications is in the food and beverage industry, where it is used as a flavoring agent. Its refreshing and citrus-like aroma enhances the sensory profile of food products, making it a popular choice for flavor formulations. Additionally, alpha-terpinene is employed in the formulation of beverages, perfumes, and cosmetics, where its aromatic properties can improve product appeal.

Alpha-terpinene is also known for its antimicrobial and antifungal properties, making it a valuable compound in the pharmaceutical and cosmetic industries. Research has shown that it can effectively inhibit the growth of various pathogenic microorganisms, including bacteria and fungi. This has led to its incorporation into natural antibacterial and antifungal formulations, where it serves as a safe and effective alternative to synthetic preservatives.

Furthermore, alpha-terpinene exhibits potential antioxidant properties, which contribute to its role in promoting overall health. Antioxidants are essential for neutralizing free radicals in the body, thereby reducing oxidative stress and preventing cellular damage. Studies have indicated that alpha-terpinene can help mitigate oxidative damage, supporting its use in dietary supplements aimed at improving health and wellness.

In the agricultural sector, alpha-terpinene has garnered attention for its potential as a natural pesticide. Its insecticidal properties have been studied for use in pest management strategies, offering an eco-friendly alternative to synthetic pesticides. This aligns with the growing demand for sustainable agricultural practices and the reduction of chemical residues in food products.

Research into alpha-terpinene's effects continues to expand, focusing on its pharmacological potential and mechanisms of action. Its anti-inflammatory properties are of particular interest, as they may play a role in preventing chronic diseases associated with inflammation.

In conclusion, alpha-terpinene is a versatile chemical substance with a rich history and diverse applications. From its discovery in the essential oils of plants to its use as a flavoring agent, antimicrobial agent, and potential natural pesticide, alpha-terpinene demonstrates its significance across various industries. As research continues to unveil its beneficial properties, alpha-terpinene is poised to play an increasingly important role in health, wellness, and sustainable practices.

References

2003. Mechanism of inhibition of lipid peroxidation by gamma-terpinene, an unusual and potentially useful hydrocarbon antioxidant. Journal of Agricultural and Food Chemistry, 51(7).
DOI: 10.1021/jf020993f

2021. Magnaporthe oryzae systemic defense trigger 1 (MoSDT1)-mediated metabolites regulate defense response in Rice. BMC Plant Biology, 21(1).
DOI: 10.1186/s12870-020-02821-6

2012. The Composition of Volatile Aroma Components, Flavanones, and Polymethoxylated Flavones in Shiikuwasha (Citrus depressa Hayata) Peels of Different Cultivation Lines. Journal of Agricultural and Food Chemistry, 60(30).
DOI: 10.1021/jf301848s