Propylparaben
[CAS# 94-13-3]

Identification

• Classification: Organic raw materials >> Amino compound >> Sulfonic acid amino compound
• Name: Propylparaben
• Synonyms: Propyl paraben; Propyl p-hydroxybenzoate; Propyl 4-hydroxybenzoate; p-Hydroxybenzoic acid propyl ester; Propyl Butex; Propyl Chemosept; 4-Hydroxybenzoic acid propyl ester
• Molecular Formula: C₁₀H₁₂O₃
• Molecular Weight: 180.20
• CAS Registry Number: 94-13-3
• EC Number: 202-307-7
• SMILES: CCCOC(=O)C1=CC=C(C=C1)O

Properties

• Water solubility: <0.1 g/100 mL at 12 °C
• Density: 1.1±0.1 g/cm³, Calc.^*
• Melting point: 95-99 °C
• Index of Refraction: 1.532, Calc.^*
• Boiling Point: 294.3±13.0 °C (760 mmHg), Calc.^*
• Flash Point: 124.6±12.6 °C, Calc.^*, 180 °C

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H334-H335-H4112
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Specific target organ toxicity - single exposure	STOT SE	3	H336
Serious eye damage	Eye Dam.	1	H318
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2A	H319
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Skin sensitization	Skin Sens.	1B	H317
Respiratory sensitization	Resp. Sens.	1	H334
Acute toxicity	Acute Tox.	4	H332

Discovery and Applications

Propylparaben, chemically known as propyl 4-hydroxybenzoate, is an organic compound widely used as a preservative in various industries. It belongs to the paraben family of compounds, which are esters of p-hydroxybenzoic acid. Propylparaben was first synthesized in the early 20th century, with its preservative properties recognized soon after. Its discovery marked a significant advancement in the ability to extend the shelf life of products, particularly in the cosmetics and food industries.

The primary application of propylparaben is as a preservative in cosmetics and personal care products. It is effective against a broad spectrum of microorganisms, including bacteria and fungi, making it an ideal choice for products that are susceptible to microbial contamination. Common formulations that utilize propylparaben include shampoos, lotions, creams, and makeup products. By preventing spoilage and maintaining product integrity, propylparaben contributes to consumer safety and satisfaction.

In addition to its role in cosmetics, propylparaben is also employed as a preservative in the food industry. It is used to extend the shelf life of various food products, preventing the growth of spoilage organisms and maintaining freshness. The compound is generally recognized as safe (GRAS) by regulatory authorities when used within specified limits, making it a popular choice among food manufacturers.

Propylparaben's chemical properties also make it useful in the pharmaceutical industry. It is often included in formulations of medications and vaccines, where it serves a similar preservative function. Its effectiveness in preventing microbial growth ensures the stability and safety of pharmaceutical products, which is critical for patient health.

The safety of propylparaben has been a topic of ongoing research and discussion. While it is widely regarded as safe when used in low concentrations, some studies have raised concerns about its potential endocrine-disrupting effects. This has led to increased scrutiny and regulatory reviews regarding its use in various applications. As a result, some manufacturers have begun to explore alternative preservatives that may have fewer health concerns, although propylparaben continues to be commonly used due to its proven efficacy.

Recent research has focused on the development of natural alternatives to synthetic preservatives like propylparaben. The growing demand for "clean label" products has spurred interest in plant-based preservatives, which are perceived as safer and more environmentally friendly. Despite this trend, propylparaben remains a cost-effective and reliable option for many manufacturers.

In summary, propylparaben is a widely used preservative in cosmetics, food, and pharmaceuticals, known for its effectiveness in preventing microbial growth. Its discovery and continued use reflect advancements in product safety and preservation. While safety concerns have prompted exploration of alternatives, propylparaben remains a crucial ingredient in many formulations, demonstrating its lasting significance in various industries.

References

2007. Effect of propyl paraben on the dipalmitoyl phosphatidic acid vesicles. Journal of Colloid and Interface Science, 311(2).
DOI: 10.1016/j.jcis.2007.03.052

2019. Rapid Determination of Parabens in Water Samples by Ultra-high Performance Liquid Chromatography Coupled to Time of Flight Mass Spectrometry. Analytical sciences: the international journal of the Japan Society for Analytical Chemistry, 36(6).
DOI: 10.2116/analsci.19p409

2021. Assessing the Public Health Implications of the Food Preservative Propylparaben: Has This Chemical Been Safely Used for Decades. Current Environmental Health Reports, 8(1).
DOI: 10.1007/s40572-020-00300-6