2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole
[CAS# 3864-99-1]

Identification

• Classification: Catalysts and additives >> UV absorber
• Name: 2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole
• Synonyms: 2-(5-Chloro-2H-benzotriazol-2-yl)-4,6-bis(1,1-dimethylethyl)-phenol ; 2,4-Di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol
• Molecular Formula: C₂₀H₂₄ClN₃O
• Molecular Weight: 357.88
• CAS Registry Number: 3864-99-1
• EC Number: 223-383-8
• SMILES: CC(C)(C)C1=CC(=C(C(=C1)N2N=C3C=CC(=CC3=N2)Cl)O)C(C)(C)C

Properties

• Density: 1.2±0.1 g/cm³, Calc.^*
• Melting point: 150-158 °C
• Index of Refraction: 1.596, Calc.^*
• Boiling Point: 469.2±55.0 °C (760 mmHg), Calc.^*
• Flash Point: 237.6±31.5 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS08 Warning
• Risk Statements: H372-H412
• Safety Statements: P260-P273-P319-P391-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
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	2	H371
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	3	H331

Discovery and Applications

2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, commonly known as UV-327, is an advanced chemical compound primarily used as a UV stabilizer in various polymeric applications. Its discovery was part of a broader effort in the late 20th century to develop effective light stabilizers that protect materials from the harmful effects of ultraviolet radiation, which can lead to degradation, discoloration, and loss of mechanical properties.

The molecular structure of UV-327 includes a benzotriazole moiety, which is well-regarded for its strong UV absorption capabilities. The presence of hydroxy and tert-butyl substituents enhances its solubility and thermal stability, making it an effective additive for a variety of materials. This unique structure not only provides excellent UV protection but also improves the overall performance of products that incorporate it.

One of the primary applications of UV-327 is in the field of plastics, particularly in the stabilization of polyolefins like polyethylene and polypropylene. These materials are widely used in consumer goods, packaging, and automotive parts due to their favorable mechanical properties and cost-effectiveness. However, they are also susceptible to UV-induced degradation. By incorporating UV-327 into these polymers, manufacturers can significantly enhance their longevity and maintain their physical properties even when exposed to harsh sunlight.

In addition to polyolefins, UV-327 is also employed in the stabilization of other polymers, including polystyrene, polyvinyl chloride (PVC), and thermoplastic elastomers. Its ability to prevent UV-induced discoloration and degradation is crucial in applications where aesthetics and functionality are paramount. For instance, in outdoor furniture and automotive interiors, the use of UV-327 helps retain the original appearance and performance of the materials over extended periods of exposure to sunlight.

The effectiveness of UV-327 is not limited to plastics. It is also utilized in coatings, adhesives, and sealants, where UV protection is essential to ensure durability and adhesion. In these applications, UV-327 acts as a photostabilizer, preventing the degradation of the coating or adhesive under UV radiation, thus extending the life of the finished product. This is particularly important in industries such as construction and automotive manufacturing, where materials must withstand environmental stresses without compromising performance.

Moreover, UV-327 is often used in conjunction with other stabilizers, such as hindered amine light stabilizers (HALS) and antioxidants, to provide synergistic effects in protecting materials from both UV radiation and thermal degradation. This multifaceted approach to stabilization enhances the overall resilience and longevity of the final products.

From a safety and regulatory perspective, UV-327 is generally regarded as safe for use in commercial applications, but it is essential to follow appropriate guidelines for handling and application. Manufacturers must ensure compliance with relevant regulations to mitigate any potential environmental impact associated with its use.

In summary, 2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole is a crucial UV stabilizer with significant applications in the plastics, coatings, and adhesives industries. Its ability to absorb UV radiation and protect materials from degradation has made it an essential additive in enhancing the durability and performance of various products. As the demand for UV-resistant materials continues to rise, the importance of UV-327 in promoting sustainability and longevity in consumer goods is expected to grow.

References

2023. Benzotriazole UV stabilizers (BUVs) as an emerging contaminant of concern: a review. Environmental Science and Pollution Research International.
DOI: 10.1007/s11356-023-30567-9

2024. Comparison of benzotriazole ultraviolet stabilizers (BUVs) removal from wastewater after subsequent stages of sequencing batch reactor (SBR) treatment process. The Science of the Total Environment.
DOI: 10.1016/j.scitotenv.2023.169813