Dimethylbiphenyl Diisocyanate

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Abbreviation:TODI

Chemical Name: 3,3′-Dimethyl-4,4′-biphenyl diisocyanate

Synonyms:o-Tolidine diisocyanate, Dimethylbiphenyl diisocyanate, etc.

Molecular Formula: C₁₆H₁₂N₂O₂

Molecular Weight: 264.28

CAS Number: 91-97-4

EINECS Number:202-112-7

Structural Formula:

Physical and Chemical Properties

At room temperature, it is a white solid granule with a purity of over 99.0%. Melting point is 70–72°C, boiling point (667 Pa) is 195–197°C, relative density (80°C) is 1.197, and flash point (COC open cup) is 218°C. It is insoluble in water and reacts slowly with water. Soluble in acetone, carbon tetrachloride, kerosene, benzene, chlorobenzene, etc. NCO content is approximately 31.8%.

Characteristics and Uses

The TODI molecule has a symmetrical structure with two benzene rings. Due to the steric hindrance effect of the ortho-methyl groups, its reactivity is lower than that of TDI and MDI. Polyurethane elastomers prepared from TODI, oligomeric polyols, and MOCA have similar physical properties to NDI elastomers, such as excellent heat resistance, hydrolysis resistance, and mechanical properties. Prepolymers made from TODI can be stored stably for a certain period, and due to their longer pot life (working time), they are easier to handle than NDI-type elastomer systems.

TODI can be used in many fields, including: seals (oil seals, piston rings, water seals, etc.), automotive parts (grilles, shock absorbers, roofs, doors, windows, etc.), industrial conveyor belts, rollers and casters, coatings for the electronics industry, and medical devices (artificial organs, etc.).