1,2-Bis(isocyanatomethyl)benzene
[CAS# 25854-16-4]

Identification

• Classification: Chemical reagent >> Organic reagent >> Cyanate ester / isocyanate
• Name: 1,2-Bis(isocyanatomethyl)benzene
• Synonyms: o-Xylylene diisocyanate
• Molecular Formula: C₁₀H₈N₂O₂
• Molecular Weight: 188.18
• CAS Registry Number: 25854-16-4
• EC Number: 247-299-6
• SMILES: C1=CC=C(C(=C1)CN=C=O)CN=C=O

Properties

• Solubility: 138.9 mg/L (25 ºC water)
• Density: 1.1±0.1 g/cm³, Calc.^*
• Index of Refraction: 1.551, Calc.^*
• Melting point: 81.94 ºC
• Boiling Point: 288.2±33.0 ºC (760 mmHg), Calc.^*, 291.48 ºC
• Flash Point: 116.6±30.7 ºC, Calc.^*

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

Safety Data

• Hazard Symbols: GHS06;GHS07;GHS08 Danger
• Hazard Statements: H315-H317-H319-H330-H334-H335
• Precautionary Statements: P233-P260-P261-P264-P264+P265-P271-P272-P280-P284-P302+P352-P304+P340-P305+P351+P338-P316-P319-P320-P321-P332+P317-P333+P317-P337+P317-P342+P316-P362+P364-P403-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 sensitization	Skin Sens.	1	H317
Respiratory sensitization	Resp. Sens.	1	H334
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	1	H330

Discovory and Applicatios

1,2-Bis(isocyanatomethyl)benzene is an organic compound that belongs to the class of aromatic diisocyanates, known for its important role in the production of polyurethane materials. This compound, also referred to as toluene diisocyanate (TDI), is a derivative of benzene with two isocyanate groups (-NCO) attached to the methyl positions. The discovery of diisocyanates, including 1,2-bis(isocyanatomethyl)benzene, dates back to the early 20th century when chemists were investigating new compounds that could lead to the development of synthetic polymers. Its significance in the chemical industry grew as the demand for versatile, durable polymers increased.

1,2-Bis(isocyanatomethyl)benzene’s chemical structure consists of a benzene ring with two methyl groups attached at the 1 and 2 positions, each of which is substituted with an isocyanate group. This structure enables the compound to readily participate in polymerization reactions with polyols, forming long-chain polymers known as polyurethanes. The reactivity of the isocyanate groups allows them to form strong covalent bonds with hydroxyl groups (-OH) in polyols, leading to the formation of urethane linkages. This reaction is the foundation of polyurethane chemistry, which has wide-ranging applications.

The primary application of 1,2-bis(isocyanatomethyl)benzene is in the production of polyurethane foams. These foams can be either flexible or rigid, depending on the type of polyol used in the reaction and the reaction conditions. Flexible polyurethane foams are used extensively in furniture, mattresses, automotive seating, and packaging due to their resilience and cushioning properties. Rigid foams, on the other hand, are employed in insulation materials for buildings, refrigeration systems, and industrial applications, providing excellent thermal insulation and structural support.

In addition to foams, 1,2-bis(isocyanatomethyl)benzene is also utilized in the production of polyurethane elastomers, coatings, adhesives, and sealants. Polyurethane elastomers are valued for their flexibility, toughness, and resistance to wear, making them suitable for use in applications such as wheels, tires, and gaskets. Polyurethane coatings, which provide protective finishes on surfaces, offer advantages such as chemical resistance, durability, and aesthetic appeal. These coatings are used in industries ranging from automotive to aerospace and construction, where high-performance materials are required.

The adhesive properties of 1,2-bis(isocyanatomethyl)benzene-based polyurethanes are particularly important in industries where strong, durable bonds are necessary, such as in the manufacture of composite materials, laminates, and various construction materials. Sealants made from polyurethane systems are also highly valued for their flexibility and long-term performance in sealing joints and gaps in buildings and infrastructure.

Although 1,2-bis(isocyanatomethyl)benzene has proven to be a valuable chemical in the creation of polyurethane materials, it is important to note the potential health and environmental concerns associated with its use. Diisocyanates, including 1,2-bis(isocyanatomethyl)benzene, can pose risks to human health, particularly through inhalation or skin contact. They are known to cause respiratory irritation and sensitization, which can lead to occupational asthma in workers who are exposed to them during the manufacturing process. As a result, industries using this compound are subject to stringent regulations regarding worker safety, including the use of personal protective equipment (PPE) and proper ventilation systems.

The environmental impact of diisocyanates is also a consideration, as improper disposal or release into the environment can lead to harmful effects on ecosystems. However, ongoing research into the development of safer, more sustainable alternatives to traditional diisocyanates continues, with the aim of minimizing these risks while retaining the beneficial properties of polyurethane materials.

In summary, 1,2-bis(isocyanatomethyl)benzene plays a critical role in the production of polyurethane foams, elastomers, coatings, adhesives, and sealants, contributing to numerous industries due to its versatility and performance-enhancing characteristics. Despite the challenges associated with its health and environmental impact, it remains a key component in modern material science and industrial applications.