2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)benzotriazole
[CAS# 3846-71-7]

Identification

• Classification: Catalysts and additives >> UV absorber
• Name: 2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)benzotriazole
• Synonyms: 2-(2H-benzotriazol-2-yl)-4,6-di-tert-butylphenol; 2-(3,5-Di-tert-butyl-2-hydroxyphenyl)-2H-benzotriazole; UV-320
• Molecular Formula: C₂₀H₂₅N₃O
• Molecular Weight: 323.44
• CAS Registry Number: 3846-71-7
• EC Number: 223-346-6
• SMILES: CC(C)(C)C1=CC(=C(C(=C1)N2N=C3C=CC=CC3=N2)O)C(C)(C)C

Properties

• Density: 1.1±0.1 g/cm³, Calc.^*
• Melting point: 152-154 °C
• Index of Refraction: 1.586, Calc.^*
• Boiling Point: 444.0±55.0 °C (760 mmHg), Calc.^*
• Flash Point: 222.3±31.5 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS08 Warning
• Risk Statements: H351-H373-H412
• Safety Statements: P203-P260-P273-P280-P318-P319-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Carcinogenicity	Carc.	2	H351

Discovery and Applications

2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, commonly known as UV-329, is a chemical compound primarily used as a UV stabilizer in various industrial applications. Its discovery can be traced back to the late 20th century when there was a growing need for materials that could withstand the damaging effects of ultraviolet (UV) radiation. As industries expanded and the use of plastics and coatings increased, researchers sought effective additives that would enhance the durability and longevity of these materials under UV exposure.

UV-329 belongs to a class of compounds known as benzotriazoles, which are characterized by their ability to absorb UV radiation and convert it into harmless heat. The structure of UV-329 features a benzotriazole moiety that provides strong UV absorption, coupled with a hydroxy group and tert-butyl substituents that enhance its thermal stability and solubility in various polymer matrices. This combination makes it particularly effective in protecting polymers from photodegradation.

One of the primary applications of UV-329 is in the stabilization of polyolefins, such as polyethylene and polypropylene, which are widely used in packaging, automotive components, and consumer goods. These materials are susceptible to UV degradation, which can lead to discoloration, loss of mechanical strength, and reduced lifespan. By incorporating UV-329 into these polymers, manufacturers can significantly extend the service life of their products, ensuring they remain functional and aesthetically pleasing for longer periods.

In addition to polyolefins, UV-329 is also used in other polymers, including polystyrene, polyvinyl chloride (PVC), and thermoplastic elastomers. Its effectiveness as a UV stabilizer has made it a popular choice in the coatings industry as well, where it is added to paints, varnishes, and other surface coatings to protect against UV-induced fading and deterioration. This application is particularly important in outdoor products, where prolonged exposure to sunlight can lead to significant degradation.

The use of UV-329 is not limited to plastics and coatings; it is also employed in the formulation of adhesives and sealants. These products often require enhanced UV resistance to maintain their bond strength and integrity when exposed to sunlight. The addition of UV-329 helps ensure that adhesives and sealants remain effective over time, even in challenging environments.

Furthermore, the versatility of UV-329 allows it to be used in combination with other additives, such as antioxidants and hindered amine light stabilizers (HALS), to provide synergistic effects in protecting materials from both UV and thermal degradation. This multifaceted approach to stabilization enhances the overall performance and longevity of the end products.

Safety and regulatory considerations surrounding the use of UV-329 are important, as with any chemical substance. It is classified as a low-toxicity compound, but it is essential to follow appropriate guidelines for handling and usage to ensure safety in manufacturing and application processes.

In summary, 2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)benzotriazole is a vital UV stabilizer with widespread applications in the plastics, coatings, adhesives, and sealants industries. Its ability to absorb UV radiation and protect materials from photodegradation has made it an essential component in enhancing the durability and performance of various products. As the demand for UV-resistant materials continues to grow, the importance of UV-329 in promoting sustainability and longevity in consumer goods is expected to increase.

References

2008. A 52-Week Repeated Dose Toxicity Study of Ultraviolet Absorber 2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)benzotriazole in Rats. Drug and Chemical Toxicology, 31(1).
DOI: 10.1080/01480540701688758

2023. Benzotriazole UV stabilizers (BUVs) as an emerging contaminant of concern: a review. Environmental science and pollution research international, 30(52).
DOI: 10.1007/s11356-023-30567-9