5-Isopropyl-2-methylphenol
[CAS# 499-75-2]

Identification

• Classification: Natural product >> Natural phenols
• Name: 5-Isopropyl-2-methylphenol
• Synonyms: Methyl-5-(1-methylethyl)phenol; Hydroxy-p-cymene; Carvacrol; Isothymol
• Molecular Formula: C₁₀H₁₄O
• Molecular Weight: 150.22
• CAS Registry Number: 499-75-2
• EC Number: 207-889-6
• FEMA: 2245
• SMILES: CC1=C(C=C(C=C1)C(C)C)O

Properties

• Density: 0.97
• Melting point: 3 °C
• Boiling point: 238 °C
• Refractive index: 1.521-1.528
• Flash point: 85 °C
• Water solubility: Insoluble

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H317-H319
• Safety Statements: P261-P264-P264+P265-P270-P272-P280-P301+P317-P302+P352-P305+P351+P338-P321-P330-P332+P317-P333+P317-P337+P317-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Skin sensitization	Skin Sens.	1	H317
Skin corrosion	Skin Corr.	1B	H314
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Serious eye damage	Eye Dam.	1	H318
Skin sensitization	Skin Sens.	1B	H317
Skin corrosion	Skin Corr.	1A	H314

• Transport Information: UN 3265

Discovery and Applications

5-Isopropyl-2-methylphenol, commonly known as thymol, is a natural monoterpene phenol with a distinctive aromatic odor that is found primarily in thyme oil. Thymol was first discovered in the 19th century by scientists studying thyme essential oil, commonly known as thyme. Thymol extracted from thyme oil has powerful antiseptic properties that have been used in traditional medicine for centuries. Today, thymol is also extracted from other plants, such as oregano and various mints.

The most important medicinal application of thymol is as an antiseptic. It is effective in killing bacteria and fungi and is a key ingredient in many over-the-counter mouthwashes and topical disinfectants. Thymol's effectiveness against oral pathogens helps reduce plaque formation and prevent gum disease, making it a key ingredient in dental hygiene products.

In traditional and modern medicine, thymol is used in cough syrups and lozenges for its soothing properties on the respiratory tract. It helps relieve cough and cold symptoms, reduces throat irritation, and provides a mild numbing effect.

Thymol is an environmentally friendly agricultural biopesticide. Its natural origin and low toxicity make it ideal for organic farming, where it can be used to control pests such as mites, aphids and fungal pathogens. Thymol-based solutions offer an alternative to synthetic pesticides, promoting sustainable agricultural practices and reducing chemical residues in crops.

In veterinary medicine, thymol is used in veterinary medicine to maintain the health of livestock. Its antimicrobial properties help prevent animal infections and improve the overall hygiene of the farming environment.

Thymol's antimicrobial benefits extend to industrial and domestic applications. It is used as a preservative in cosmetics and food to inhibit the growth of microorganisms. In addition, thymol is a common ingredient in natural cleaners and disinfectants, providing effective sanitation without the use of harsh chemicals. Thymol's pleasant herbaceous aroma makes it a popular flavoring agent in the food industry, adding a unique taste to products such as candies and beverages. Its strong aromatic scent is also used in perfumes, adding a fresh herbal aroma to various fragrances.

Thymol is considered safe when used in controlled amounts, but concentrated forms should be handled with care to avoid irritation. Its low environmental impact and biodegradability make it a top choice for applications that require minimal ecological damage.

References

2025. Preparation and characterization of carvacrol/soybean protein isolate composite film with efficient antimicrobial and antioxidant activities and its application in grape preservation. Food Chemistry.
DOI: 10.1016/j.foodchem.2024.141572

2025. Impacts of chitosan/pullulan/carvacrol film on the quality and microbial diversity of refrigerated goat meat. Meat Science.
DOI: 10.1016/j.meatsci.2024.109704

2025. Antimicrobial efficacy of carvacrol-loaded curdlan hydrogels for enhancing shelf-life in seafood packaging applications. International Journal of Food Microbiology.
DOI: 10.1016/j.ijfoodmicro.2024.110976