4-Chloro-3-methylphenol
[CAS# 59-50-7]

Identification

• Classification: Natural product >> Natural phenols
• Name: 4-Chloro-3-methylphenol
• Synonyms: 6-Chloro-3-hydroxytoluene; 2-Chloro-5-hydroxytoluene; 3-Methyl-4-chlorophenol; p-Chloro-m-cresol; 4-Chloro-m-cresol
• Molecular Formula: C₇H₇ClO
• Molecular Weight: 142.58
• CAS Registry Number: 59-50-7
• EC Number: 200-431-6
• SMILES: CC1=C(C=CC(=C1)O)Cl

Properties

• Density: 1.2±0.1 g/cm³ Calc.^*, 1.37 g/mL (Expl.)
• Melting point: 63 - 65 °C (Expl.)
• Boiling point: 235.0 °C 760 mmHg (Calc.)^*, 235 °C (Expl.)
• Flash point: 93.4±21.8 °C (Calc.)^*, 118 °C (Expl.)
• Solubility: DMSO: 30mg/mL, water: 4 g/L (20 °C) (Expl.)
• Index of refraction: 1.566 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS05;GHS07;GHS09 Danger
• Risk Statements: H302-H312-H314-H317-H318-H335-H400-H412
• Safety Statements: P260-P261-P264-P264+P265-P270-P271-P272-P273-P280-P301+P317-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P319-P321-P330-P333+P317-P362+P364-P363-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	4	H302
Serious eye damage	Eye Dam.	1	H318
Acute toxicity	Acute Tox.	4	H312
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin corrosion	Skin Corr.	1C	H314
Skin sensitization	Skin Sens.	1B	H317
Skin corrosion	Skin Corr.	1B	H314
Skin corrosion	Skin Corr.	1	H314
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410

• Transport Information: UN 2669; UN 3077

Discovery and Applications

4-Chloro-3-methylphenol, also known as chlorocresol, is an aromatic organic compound belonging to the class of chlorinated phenols. It is characterized by a phenol ring substituted with a chlorine atom at the 4-position and a methyl group at the 3-position. The compound has been known and studied since the early 20th century, particularly for its antimicrobial and antiseptic properties.

The discovery of chlorocresol and related chlorinated phenols arose from efforts to develop effective antiseptics and disinfectants. These compounds were found to possess strong antimicrobial activity against a broad spectrum of bacteria and fungi, which led to their widespread use in healthcare and industrial settings.

4-Chloro-3-methylphenol is primarily utilized as a preservative and antimicrobial agent in pharmaceutical, cosmetic, and personal care products. Its ability to inhibit microbial growth helps extend the shelf life of products and reduce the risk of contamination during use. It is commonly found in topical formulations such as creams, ointments, lotions, and solutions, where it helps maintain product sterility and safety.

In pharmaceutical preparations, chlorocresol is used as a preservative in multi-dose vials, vaccines, and other parenteral products. Its effectiveness in aqueous and hydroalcoholic systems makes it suitable for a variety of dosage forms. The compound also exhibits low toxicity at the concentrations typically employed, which supports its safe use in medicinal products.

Cosmetic and personal care industries benefit from the incorporation of 4-chloro-3-methylphenol in products such as shampoos, skin cleansers, deodorants, and antiseptic wipes. Its antimicrobial properties prevent spoilage and contamination, contributing to product stability and consumer safety. Furthermore, its compatibility with many other cosmetic ingredients enhances its versatility as a preservative.

From a chemical perspective, 4-chloro-3-methylphenol is stable under normal storage conditions but may degrade under extreme pH or temperature. It is moderately soluble in water and more soluble in organic solvents, which influences its formulation and application. The presence of both a chlorine atom and a methyl group on the phenol ring modulates its antimicrobial potency and physicochemical properties.

Toxicological studies have established that chlorocresol is generally well tolerated in the concentrations used for preservation. It has low acute toxicity and is not classified as a significant irritant or sensitizer for most users. Regulatory agencies have approved its use within specified limits to ensure product safety.

In addition to its preservative functions, 4-chloro-3-methylphenol has been explored for use in antiseptic formulations applied to skin and mucous membranes. Its antimicrobial efficacy helps reduce infection risk in minor wounds, surgical sites, and dermatological conditions.

In summary, 4-chloro-3-methylphenol is a chlorinated phenol compound discovered for its antimicrobial activity and developed as a preservative and antiseptic. Its application spans pharmaceuticals, cosmetics, and personal care products where it provides effective microbial control while maintaining safety and stability. The compound’s chemical and biological properties ensure its continued relevance in formulations designed to preserve product integrity and protect users.

References

2010. In Vitro Dermal Penetration of 4-Chloro-3-Methylphenol from Commercial Metal Working Fluid and Aqueous Vehicles. Journal of Toxicology and Environmental Health, Part A
DOI: 10.1080/15287394.2010.497444

2010. Determination of Phenolic Disinfectants in Consumer Products by Capillary Electrophoresis with Amperometric Detection. Journal of Chromatographic Science
DOI: 10.1093/chromsci/48.7.584

1993. The Effect of Phenol on the Electrolyte Flocculation of Certain Polymeric Dispersions to Thixotropic Gels. Pharmaceutical Research
DOI: 10.1023/a:1018930709603