3,3'-Dimethyl-4,4'-biphenylene diisocyanate
[CAS# 91-97-4]

Identification

• Classification: Organic raw materials >> Aryl compounds >> Biphenyl compounds
• Name: 3,3'-Dimethyl-4,4'-biphenylene diisocyanate
• Synonyms: 3,3'-Dimethylbiphenyl-4,4'-diyl diisocyanate
• Molecular Formula: C₁₆H₁₂N₂O₂
• Molecular Weight: 264.29
• CAS Registry Number: 91-97-4
• EC Number: 202-112-7
• SMILES: CC1=C(C=CC(=C1)C2=CC(=C(C=C2)N=C=O)C)N=C=O

Properties

• Density: 1.197 (80 ºC)
• Melting point: 70-72 ºC
• Boiling point: 195-197 ºC (667 Pa)
• Flash point: 218 ºC

Safety Data

• Hazard Symbols: GHS07;GHS08;GHS09 Danger
• Hazard Statements: H317-H332-H334-H400-H410
• Precautionary Statements: P233-P260-P261-P271-P272-P273-P280-P284-P302+P352-P304+P340-P317-P321-P333+P317-P342+P316-P362+P364-P391-P403-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H332
Respiratory sensitization	Resp. Sens.	1	H334
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Skin sensitization	Skin Sens.	1	H317
Skin sensitization	Skin Sens.	1A	H317
Germ cell mutagenicity	Muta.	2	H341
Acute toxicity	Acute Tox.	4	H312
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H302

Discovory and Applicatios

3,3'-Dimethyl-4,4'-biphenylene diisocyanate is a significant organic compound primarily used in the synthesis of polyurethanes and other polymeric materials. This compound, characterized by two isocyanate functional groups attached to a biphenylene backbone, plays a vital role in various industrial applications due to its reactivity and the versatility of the products derived from it. The discovery and development of 3,3'-dimethyl-4,4'-biphenylene diisocyanate is tied to the broader exploration of aromatic isocyanates and their utility in polymer chemistry.

The synthesis of 3,3'-dimethyl-4,4'-biphenylene diisocyanate involves the reaction of 3,3'-dimethyl-4,4'-biphenylene with phosgene or other isocyanate precursors. This process has been refined since its initial discovery in the mid-20th century, during which researchers aimed to develop new isocyanates with enhanced properties for polymer production. The unique structure of 3,3'-dimethyl-4,4'-biphenylene diisocyanate provides improved thermal stability and mechanical properties to the polymers produced from it, making it an attractive choice for various applications.

One of the primary applications of 3,3'-dimethyl-4,4'-biphenylene diisocyanate is in the production of polyurethane elastomers. These materials are known for their flexibility, durability, and resistance to abrasion and chemicals, making them suitable for a wide range of applications, including automotive components, footwear, coatings, and adhesives. The incorporation of this diisocyanate into polyurethane formulations allows for the development of materials with tailored properties, enhancing their performance in demanding environments.

Additionally, 3,3'-dimethyl-4,4'-biphenylene diisocyanate is used in the synthesis of coatings and adhesives. Its isocyanate groups can react with polyols to form polyurethanes that exhibit excellent adhesion to various substrates, including metals, plastics, and composites. This property is particularly beneficial in industrial applications where strong bonding is essential for product performance and longevity. The compound’s versatility also allows it to be employed in formulating heat-resistant coatings that protect surfaces from environmental degradation.

In the realm of medical applications, 3,3'-dimethyl-4,4'-biphenylene diisocyanate and its derivatives have shown potential for use in biocompatible materials. Research is ongoing to explore its application in developing implants and devices that require both mechanical strength and compatibility with biological tissues. The ability to modify the properties of polyurethane materials through the incorporation of this diisocyanate offers opportunities for innovation in biomedical engineering.

While the compound exhibits numerous benefits in industrial applications, safety and environmental considerations are crucial. 3,3'-Dimethyl-4,4'-biphenylene diisocyanate is classified as a hazardous material, and exposure can lead to respiratory irritation and sensitization. Therefore, appropriate safety measures, including personal protective equipment and adequate ventilation, are essential when handling this compound. Regulatory agencies have established guidelines to ensure safe practices in its use, emphasizing the importance of workplace safety and environmental protection.

Research into 3,3'-dimethyl-4,4'-biphenylene diisocyanate continues to expand, focusing on enhancing its applications and exploring greener synthesis routes. The principles of green chemistry aim to reduce the environmental impact associated with the production and use of isocyanates while maintaining their desirable properties in polymer chemistry.

In conclusion, 3,3'-Dimethyl-4,4'-biphenylene diisocyanate is a versatile compound with significant applications in the production of polyurethanes, coatings, adhesives, and potential biomedical materials. Its discovery and ongoing research reflect advancements in organic chemistry and materials science, and continued exploration may uncover new applications and improved methodologies that enhance its utility across various industries.

References

2021. Supramolecular organogel of polyureas containing POSS units in the main chain: dependence on the POSS and comonomer structures. Polymer Journal, 53(11).
DOI: 10.1038/s41428-021-00578-9