Cyanuric acid
[CAS# 108-80-5]

Identification

• Classification: Catalysts and additives >> UV absorber
• Name: Cyanuric acid
• Synonyms: 1,3,5-Triazine-2,4,6-triol; Trihydroxy-1,3,5-triazine; Trihydroxycyanidine; Tricarbimide
• Molecular Formula: C₃H₃N₃O₃
• Molecular Weight: 129.07
• CAS Registry Number: 108-80-5
• EC Number: 203-618-0
• SMILES: C1(=O)NC(=O)NC(=O)N1

Properties

• Density: 2.0±0.1 g/cm³, Calc.^*, 2.5 g/mL
• Melting point: 360 °C
• Index of Refraction: 1.748, Calc.^*
• Boiling Point: 793.4±43.0 °C (760 mmHg), Calc.^*
• Flash Point: 433.6±28.2 °C, Calc.^*
• Water solubility: 0.3 g/100mL (25 °C)

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H319-H335
• Safety Statements: P261-P264+P265-P271-P280-P304+P340-P305+P351+P338-P319-P337+P317-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	4	H332

Discovery and Applications

Cyanuric acid, with the molecular formula C3H3N3O3, is a heterocyclic compound featuring a six-membered ring composed of three nitrogen atoms and three carbon atoms, with each carbon atom bonded to an oxygen atom through a carbonyl group. This compound appears as a white, crystalline solid and is primarily known for its applications in water treatment, agriculture, and the production of specialty chemicals.

The discovery of cyanuric acid dates back to the early 19th century when it was first synthesized in 1834 by German chemist Heinrich W. A. Wöhler. He obtained it through the reaction of urea and sodium cyanate. The structural elucidation of cyanuric acid was later confirmed by various chemists, leading to a deeper understanding of its properties and potential applications. Over the years, cyanuric acid has gained recognition for its unique chemical behavior and versatility in different industries.

One of the most prominent applications of cyanuric acid is in the swimming pool industry, where it is used as a stabilizer for chlorine. When added to pool water, cyanuric acid helps prevent the degradation of chlorine by sunlight, extending its effectiveness and reducing the frequency of chlorine replenishment. This stabilizing effect is crucial for maintaining water quality and sanitation in swimming pools, ensuring a safe and pleasant environment for users. Its widespread use in the pool industry has made it an essential chemical for pool maintenance.

In addition to its role in water treatment, cyanuric acid is used as a herbicide and fungicide in agriculture. Its derivatives, such as cyanoacrylate, exhibit herbicidal properties and are effective in controlling various weeds and pests. This application contributes to improved crop yields and helps manage unwanted vegetation in agricultural settings. Cyanuric acid's ability to enhance the effectiveness of certain agricultural chemicals makes it a valuable resource in modern farming practices.

Cyanuric acid is also utilized in the synthesis of other chemical compounds, including biocides and adhesives. Its unique structure allows it to participate in various chemical reactions, leading to the formation of more complex molecules. For instance, cyanuric acid derivatives are often used in the production of water-soluble resins and cross-linking agents, which find applications in coatings and adhesives.

Despite its beneficial applications, cyanuric acid has been the subject of environmental and health discussions. While it is generally considered safe in the concentrations typically used in pool maintenance and agriculture, excessive levels can lead to water quality issues. In aquatic environments, high concentrations of cyanuric acid can potentially harm fish and other aquatic organisms. Therefore, monitoring and managing its use in both recreational and agricultural contexts is essential to minimize environmental impact.

In summary, cyanuric acid is a significant heterocyclic compound with diverse applications in water treatment, agriculture, and specialty chemical production. Its discovery in the 19th century paved the way for its use as a chlorine stabilizer in swimming pools and as a herbicide in agriculture. As research continues to explore new applications and address environmental concerns, cyanuric acid is expected to remain an important substance in various industries.

References

2010. Prebiotic Synthesis of Protobiopolymers Under Alkaline Ocean Conditions. Origins of Life and Evolution of the Biosphere.
DOI: 10.1007/s11084-010-9232-z

2007. An Experimental and Theoretical Study of the Formation of Nanostructures of Self-Assembled Cyanuric Acid through Hydrogen Bond Networks on Graphite. The Journal of Physical Chemistry B.
DOI: 10.1021/jp0706984

2009. Hydrogen-Bonded Molecular Networks of Melamine and Cyanuric Acid on Thin Films of NaCl on Au(111). Small.
DOI: 10.1002/smll.200900301