What Is 2-Phenylphenol

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Last updated: April 15, 2026

Quick Answer: 2-Phenylphenol is an organic compound with the molecular formula C₁₂H₁₀O, commonly used as a fungicide and disinfectant. It has been registered for use in the United States since 1949 and is often found in household cleaning products and industrial preservatives.

Key Facts

2-Phenylphenol has the chemical formula C₁₂H₁₀O and a molecular weight of 170.21 g/mol
It was first registered for use as a pesticide in the U.S. in 1949 by the EPA
The compound is commonly used at concentrations between 0.1% and 2% in disinfectants
It is classified as a Group D carcinogen by the EPA—'not classifiable as to human carcinogenicity'
2-Phenylphenol is frequently detected in post-harvest treatments of citrus fruits to prevent mold

Overview

2-Phenylphenol is a synthetic organic compound widely used for its antimicrobial properties. It appears as white to light pink crystalline solid and is soluble in alcohol and other organic solvents but poorly soluble in water.

Due to its effectiveness against fungi and bacteria, it is commonly incorporated into disinfectants, sanitizers, and preservatives. Its use spans multiple industries, including agriculture, healthcare, and consumer goods.

Chemical structure: The molecule consists of a phenol ring with a second phenyl group attached at the 2-position, giving it the IUPAC name 2-phenylphenol and contributing to its stability and reactivity.
Molecular weight: It has a precise molecular weight of 170.21 g/mol, which influences its formulation in various industrial and household applications.
Physical state: At room temperature, 2-phenylphenol exists as a crystalline solid with a melting point of approximately 53–55°C, making it easy to handle and store.
Solubility: It dissolves readily in ethanol and acetone but has low water solubility—only about 0.8 g/L at 20°C, which affects its delivery methods in aqueous solutions.
Primary function: It acts primarily as a fungicide and disinfectant, particularly effective against mold and yeast in post-harvest fruit treatments and surface cleaners.

How It Works

2-Phenylphenol exerts its antimicrobial effects through disruption of microbial cell membranes and interference with cellular processes. Its mechanism makes it effective in low concentrations across various environments.

Mode of action:It disrupts cell membrane integrity in fungi and bacteria, leading to leakage of cellular contents and eventual cell death within minutes of exposure.
pH dependency: Its efficacy increases under alkaline conditions because the phenolate ion form is more active and better able to penetrate microbial cell walls.
Target organisms: It is particularly effective against Penicillium and Aspergillus species, common causes of fruit spoilage, which is why it's used in citrus packing facilities.
Concentration range: Effective disinfection typically occurs at concentrations between 0.1% and 2%, depending on the formulation and intended use environment.
Residual activity: It provides long-lasting antimicrobial protection on surfaces, making it suitable for industrial settings where repeated contamination is a concern.
Safety profile: While toxic in high doses, it is considered safe for use in consumer products when handled according to guidelines established by the EPA and FDA.

Comparison at a Glance

Below is a comparison of 2-phenylphenol with other common disinfectants based on key performance and safety metrics.

Compound	Primary Use	EPA Registration Year	Typical Concentration	Known Resistance Issues
2-Phenylphenol	Fungicide, disinfectant	1949	0.1% – 2%	Low
Chlorine bleach	Broad-spectrum disinfectant	1915	0.5% – 6%	Moderate
Quaternary ammonium compounds	Surface sanitizer	1935	0.1% – 0.5%	Increasing
Hydrogen peroxide	Oxidizing agent	1958	3% – 35%	Low
Triclosan	Antibacterial agent	1969	0.1% – 0.3%	High

This table highlights how 2-phenylphenol remains competitive due to its long history of use, low resistance development, and effectiveness at relatively low concentrations. While newer agents have emerged, its stability and targeted action keep it relevant in specific applications, especially in agriculture and food safety.

Why It Matters

Understanding the role and impact of 2-phenylphenol is essential for evaluating its safety, efficacy, and regulatory status in consumer and industrial products. Its continued use underscores its importance in public health and food preservation.

Food safety: It plays a critical role in preventing mold growth on citrus fruits, helping reduce spoilage and extend shelf life during transport and storage.
Regulatory status: Approved by the U.S. EPA and FDA for specific uses, it undergoes regular review to ensure ongoing safety for humans and the environment.
Industrial applications: Widely used in cooling tower water systems and industrial lubricants to prevent microbial contamination and system degradation.
Consumer products: Found in household disinfectants and sanitizing wipes, often listed as ortho-phenylphenol (OPP) on ingredient labels.
Environmental impact: It degrades slowly in soil and water, with a half-life of 10–30 days, requiring careful management to prevent accumulation.
Health considerations: Prolonged skin contact may cause irritation, and the ACGIH lists it as an A4 carcinogen—not classifiable due to insufficient evidence.

Despite growing scrutiny of chemical preservatives, 2-phenylphenol remains a valuable tool in microbial control due to its proven track record and targeted functionality. Ongoing research continues to assess its long-term safety and environmental footprint.