1,5-Naphthalene diisocyanate
[CAS# 3173-72-6]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Carboxylic esters and their derivatives
• Name: 1,5-Naphthalene diisocyanate
• Synonyms: 1,5-Naphthalenediisocyanate; 1,5-Diisocyanato naphthalene
• Molecular Formula: C₁₂H₆N₂O₂
• Molecular Weight: 210.19
• CAS Registry Number: 3173-72-6
• EC Number: 221-641-4
• SMILES: C1=CC2=C(C=CC=C2N=C=O)C(=C1)N=C=O

Properties

• Density: 1.2±0.1 g/cm³, Calc.^*, 1.45 g/mL
• Melting point: 130 °C
• Index of Refraction: 1.618, Calc.^*
• Boiling Point: 314.7±22.0 °C (760 mmHg), Calc.^*, 244 °C (100 torr)
• Flash Point: 128.6±27.7 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS07;GHS08 Danger
• Risk Statements: H315-H317-H319-H332-H334-H335-H412
• Safety Statements: P233-P260-P261-P264-P264+P265-P271-P272-P273-P280-P284-P302+P352-P304+P340-P305+P351+P338-P317-P319-P321-P332+P317-P333+P317-P337+P317-P342+P316-P362+P364-P403-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Respiratory sensitization	Resp. Sens.	1	H334
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H332
Skin sensitization	Skin Sens.	1	H317
Acute toxicity	Acute Tox.	2	H330
Skin sensitization	Skin Sens.	1A	H317

Discovery and Applications

1,5-Naphthalene diisocyanate (NDI) is an important aromatic diisocyanate that has garnered significant attention in the field of polymer chemistry and material science. Its discovery is rooted in the ongoing search for effective building blocks for polyurethanes and other polymers, with applications ranging from coatings to elastomers.

The synthesis of 1,5-naphthalene diisocyanate typically involves the reaction of naphthalene with phosgene or other isocyanate precursors. This reaction allows for the introduction of two isocyanate groups at the 1 and 5 positions of the naphthalene ring, resulting in a compound with unique reactivity and properties. The ability to manipulate the aromatic structure of naphthalene during synthesis has made it a valuable compound in the development of new materials.

One of the primary applications of 1,5-naphthalene diisocyanate is in the production of polyurethane elastomers. These materials are known for their excellent mechanical properties, durability, and resistance to abrasion and chemicals. By incorporating NDI into polyurethane formulations, manufacturers can achieve specific performance characteristics, such as increased heat resistance and enhanced flexibility. This versatility makes NDI a popular choice in various industries, including automotive, construction, and consumer goods.

In addition to its use in polyurethanes, 1,5-naphthalene diisocyanate has found applications in the development of coatings and adhesives. The compound’s reactivity with polyols allows for the creation of high-performance coatings that provide excellent adhesion, chemical resistance, and weatherability. These properties are particularly beneficial in applications where durability and long-lasting performance are essential, such as in industrial coatings and protective finishes for metal and plastic substrates.

Moreover, NDI has been explored for its potential use in the production of thermoplastic elastomers (TPEs). These materials combine the properties of rubber with the processability of thermoplastics, making them suitable for a wide range of applications, including automotive parts, consumer products, and medical devices. The incorporation of 1,5-naphthalene diisocyanate into TPE formulations can enhance their performance characteristics, providing greater flexibility and resilience.

While 1,5-naphthalene diisocyanate offers many advantages, safety considerations are crucial when handling this compound. Isocyanates are known to pose health risks, including respiratory irritation and sensitization. As such, proper safety measures and regulations are necessary to minimize exposure during manufacturing and processing. Regulatory agencies continue to assess the safety of diisocyanates, including NDI, to ensure they meet safety standards for use in industrial applications.

In summary, 1,5-naphthalene diisocyanate is a significant compound in the field of polymer chemistry, with applications spanning the production of polyurethanes, coatings, and thermoplastic elastomers. Its unique chemical structure and reactivity provide valuable opportunities for developing advanced materials with tailored properties. As research continues to explore the potential of NDI, its role in the manufacturing of high-performance products remains vital across various industries.

References

2011. Surface area and pore structure properties of urethane-based copolymers containing β-cyclodextrin. Journal of Colloid and Interface Science, 357(1).
DOI: 10.1016/j.jcis.2011.01.081

2013. Biomarkers of exposure in Monday morning urine samples as a long-term measure of exposure to aromatic diisocyanates. International Archives of Occupational and Environmental Health, 87(4).
DOI: 10.1007/s00420-013-0872-y

2016. The role of isocyanates in fire toxicity. Fire Science Reviews, 5(1).
DOI: 10.1186/s40038-016-0013-2