Ethylparaben
[CAS# 120-47-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Ester >> Ethyl ester compound
• Name: Ethylparaben
• Synonyms: Ethyl paraben; Ethyl p-hydroxybenzoate; 4-(Ethoxycarbonyl)phenol; Ethyl 4-hydroxybenzoate; p-Hydroxybenzoate ethyl ester; Ethyl butex; 4-Hydroxybenzoic acid ethyl ester
• Molecular Formula: C₉H₁₀O₃
• Molecular Weight: 166.17
• CAS Registry Number: 120-47-8
• EC Number: 204-399-4
• SMILES: CCOC(=O)C1=CC=C(C=C1)O

Properties

• Solubility: 10 mM (water)
• Density: 1.2±0.1 g/cm³, Calc.^*
• Melting point: 115-118 °C
• Index of Refraction: 1.539, Calc.^*
• Boiling Point: 297.5±0.0 °C (760 mmHg), Calc.^*
• Flash Point: 120.3±12.6 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS08 Danger
• Risk Statements: H334
• Safety Statements: P233-P260-P271-P284-P304+P340-P342+P316-P403-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Skin sensitization	Skin Sens.	1	H317
Aspiration hazard	Asp. Tox.	1	H304
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H302
Respiratory sensitization	Resp. Sens.	1	H334

Discovery and Applications

Ethylparaben, chemically known as ethyl 4-hydroxybenzoate, is a widely used compound in the food, pharmaceutical, and cosmetic industries as a preservative. It belongs to the paraben family of compounds, which are esters of p-hydroxybenzoic acid. Ethylparaben is characterized by the molecular formula C9H10O3 and is known for its effective antimicrobial properties. The discovery of ethylparaben dates back to the early 20th century, coinciding with the exploration of various paraben compounds as preservatives to extend the shelf life of products.

The synthesis of ethylparaben involves the esterification of p-hydroxybenzoic acid with ethanol in the presence of an acid catalyst. This process results in the formation of ethylparaben along with the release of water. The compound's ability to inhibit the growth of bacteria, yeast, and mold has made it a popular choice for various formulations, providing a means to prevent spoilage and maintain product integrity over time.

Ethylparaben is primarily used as a preservative in cosmetics and personal care products, such as lotions, shampoos, and creams. Its effectiveness in preventing microbial contamination helps to ensure the safety and stability of these products during their shelf life. Additionally, ethylparaben is utilized in pharmaceuticals, particularly in oral and topical medications, where it serves a similar preservative function to safeguard against microbial growth.

In the food industry, ethylparaben has been employed as a preservative in certain food products. Its use helps to inhibit the growth of spoilage organisms, extending the shelf life of food items while maintaining their quality. However, its application in food products is subject to regulatory scrutiny, and its use is limited in many countries due to concerns over potential health effects associated with parabens.

One of the key advantages of ethylparaben is its low toxicity and high efficacy at relatively low concentrations. It is effective across a broad pH range and is stable under various storage conditions, making it a versatile choice for formulators. Ethylparaben is often used in combination with other preservatives to enhance antimicrobial effectiveness and broaden the spectrum of protection against a variety of microorganisms.

Despite its widespread use, concerns have been raised about the safety of parabens, including ethylparaben, particularly regarding their potential endocrine-disrupting effects. Research has shown that parabens can be absorbed through the skin and may mimic estrogen in the body. As a result, regulatory agencies, such as the U.S. Food and Drug Administration (FDA) and the European Commission, have conducted assessments of parabens to determine their safety for use in consumer products. Current evaluations suggest that when used within established limits, ethylparaben is considered safe for use in cosmetics and pharmaceuticals.

The trend toward more natural and organic products has led to an increasing demand for preservative alternatives, prompting researchers to explore new compounds and methods for preserving products without synthetic preservatives. Nevertheless, ethylparaben remains a staple in the formulation of various products due to its proven effectiveness and safety profile when used appropriately.

In summary, ethylparaben is an important preservative with applications in cosmetics, pharmaceuticals, and food products. Its discovery and utilization highlight the need for effective preservation methods in consumer goods. Continued research into the safety and efficacy of ethylparaben and similar compounds will help inform regulatory decisions and consumer choices in the evolving landscape of product formulation.

References

1957. Intermediary behavior of p-hydroxybenzoic acid ethyl ester. Klinische Wochenschrift.
DOI: 10.1007/bf01485726

2024. Liquid-liquid microextraction method based on switchable hydrophilic solvent for determination of parabens in cream samples. Chemical Papers.
DOI: 10.1007/s11696-024-03627-8

2024. Simultaneous Analytical Method for Various Paraben and Alcohol Preservatives in Supposedly Natural and Organic Cosmetics by Off-line SPE-UHPLC-DAD and LC-MS/MS. Chromatographia.
DOI: 10.1007/s10337-024-04362-8