Urea
[CAS# 57-13-6]

Identification

• Classification: API >> Urinary system medication >> Dehydrated medicine
• Name: Urea
• Synonyms: Carbamide; Carbonyl diamine; Sulfur coated urea
• Molecular Formula: CH₄N₂O
• Molecular Weight: 60.05
• CAS Registry Number: 57-13-6
• EC Number: 200-315-5
• SMILES: C(=O)(N)N

Properties

• Water solubility: 8 M (20 °C)
• Density: 1.6±0.1 g/cm³, Calc.^*, 1.335 g/mL
• Melting point: 131-135 °C
• Index of Refraction: 1.528, Calc.^*, 1.484
• Boiling Point: 165.1±23.0 °C (760 mmHg), Calc.^*
• Flash Point: 53.7±22.6 °C, Calc.^*

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

Safety Data

• Safety Statements: S24/25

Discovery and Applications

Urea is a simple organic compound with the chemical formula CO(NH2)2, consisting of two amine groups (-NH2) and a carbonyl group (C=O). Its discovery dates back to the early 18th century when it was first isolated from urine by the Dutch chemist Herman Boerhaave. However, it was not until 1773 that William Cruickshank identified urea as a distinct chemical substance present in urine. The synthesis of urea from inorganic compounds was achieved by Friedrich Wöhler in 1828, marking a significant milestone in organic chemistry. Wöhler's synthesis demonstrated that organic compounds could be created from inorganic precursors, challenging the then-prevailing belief in vitalism, which posited that organic substances could only be produced by living organisms.

Urea's primary application is as a nitrogen-rich fertilizer in agriculture. It is highly soluble in water and can deliver essential nitrogen to crops, promoting growth and improving yields. Farmers widely use urea in various formulations, including granules, solutions, and as a component in controlled-release fertilizers. Its high nitrogen content, approximately 46%, makes it one of the most concentrated nitrogenous fertilizers available. This efficiency has contributed significantly to increased agricultural productivity, especially in regions where soil nitrogen levels are low.

In addition to its agricultural uses, urea is employed in various industrial applications. It serves as a key raw material in the production of plastics, particularly urea-formaldehyde resins, which are used in the manufacture of plywood, particleboard, and other composite materials. These resins are favored for their strength and resistance to moisture, making them ideal for construction and furniture applications. Urea is also utilized in the production of adhesives, coatings, and textiles.

Urea plays a crucial role in the pharmaceutical industry as well. It is used in the formulation of topical medications and creams due to its properties as a humectant, helping to retain moisture in the skin. Urea is often incorporated into dermatological products designed to treat dry skin conditions, such as eczema and psoriasis, as it can enhance the skin's hydration and promote desquamation, or the shedding of dead skin cells. Its ability to act as a keratolytic agent makes it valuable in various skincare formulations.

Furthermore, urea is used in laboratory settings as a reagent in biochemical assays and protein purification processes. It is instrumental in denaturing proteins, facilitating their separation and analysis, particularly in the study of enzyme activity and interactions. The compound’s role in protein chemistry highlights its significance in research and biotechnology.

Despite its many beneficial applications, concerns have arisen regarding the environmental impact of excessive urea use in agriculture. Overapplication can lead to soil and water pollution through the leaching of nitrates, contributing to eutrophication in aquatic ecosystems. Therefore, careful management practices are essential to minimize the environmental footprint of urea fertilizers.

Overall, urea remains a vital compound with diverse applications across agriculture, industry, and healthcare. Its discovery and subsequent synthesis have had profound implications for chemistry and the understanding of organic compounds, solidifying its status as one of the most important nitrogen sources in modern society.

References

2025. Temperature-responsive gating chitosan-based microcapsules for controlled release of urea fertilizers. Carbohydrate Polymers, 351.
DOI: 10.1016/j.carbpol.2024.122929

2025. In silico inspired design of urea noscapine congeners as anticancer agents: Chemical synthesis and experimental evaluation using breast cancer cells and a xenograft mouse model. European Journal of Medicinal Chemistry, 287.
DOI: 10.1016/j.ejmech.2024.117091

1849. The results of some experiments respecting the presence of urea in the liquor amnii and fœtal urine of the human subject. Dublin Quarterly Journal of Medical Science, 7(13).
DOI: 10.1007/bf02949641