Other Diisocyanates

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Many other diisocyanates have been reported but are not yet available as industrial products. Some are available as reagents. Several examples are given below.

Octamethylene diisocyanate (1,8-octamethylene diisocyanate or 1,8-diisocyanatooctane), with the structural formula OCN(CH2)8NCO, molecular weight 196.25, and CAS number 10124-86-4. Liquid density (25℃) is 1.007 g/mL, boiling point is 156℃/(15×133Pa), and refractive index (20℃) is 1.455. Purity is generally 98%. It is expensive.

Decamethylene diisocyanate (1,10-decamethylene diisocyanate), with the structural formula OCN(CH2)10NCO, molecular weight 224.30, and CAS number 4538-39-0.

1,12-Dodecamethylene diisocyanate (dodecamethylene diisocyanate or 1,12-diisocyanatododecane), with the structural formula OCN(CH2)12NCO, molecular weight 252.3, and CAS number 13879-35-1. It is a transparent, low-viscosity liquid with a very slight odor. The boiling point at 1.3 kPa is 198℃, and the vapor pressure at room temperature is 0.00013 Pa. Liquid density is 0.94 g/mL, boiling point (3×133Pa) is 158–159℃, flash point is 113℃, and refractive index is 1.459. Purity is generally 97%. It is expensive.

2-Methylpentane diisocyanate (1,5-diisocyanato-2-methylpentane), abbreviated as MPDI. English names include 2-methylpentane-1,5-diyl diisocyanate; 1,5-diisocyanato-2-methylpentane, etc. Its CAS number is 34813-62-21, EINECS number is 252-224-5, structural formula is OCN(CH2)3CH(CH3)CH2NCO, molecular formula is C8H12N2O2, and molecular weight is 168.19. The product purity is ≥98%. 2-Methylpentane diisocyanate is a liquid at normal temperature, with a viscosity (25℃) of approximately 3 mPa·s, a relative density (25℃) of 1.049, a refractive index (20℃) of 1.455, and a flash point of 113℃. The product purity is ≥98%. It is a branched isomer of HDI. Its trimer is used in non-yellowing polyurethane coatings.

2,4-Dimethyl-1,8-octane diisocyanate (2,4-dimethyloctane-1,8-diyl diisocyanate; 1,8-diisocyanato-2,4-dimethyloctane), molecular formula C12H20N2O2, molecular weight 224.30. CAS number 68882-56-4, EINECS number 272-571-6.

3,3′-Dimethoxybiphenyl-4,4′-diisocyanate (3,3′-dimethoxybenzidine-4,4′-diisocyanate), also known as o-dianisidine diisocyanate, CAS number 91-93-0. Molecular formula C16H12N2O4, molecular weight 296.28. Melting point 112–116℃. Reagents are available from several chemical suppliers.

4,4′-Diphenyl ether diisocyanate [diphenylether-4,4′-diisocyanate, oxybis(4-phenyl isocyanate), diphenyl oxide 4,4′-diisocyanate], molecular formula C14H8N2O3, molecular weight 252.23. CAS number 4128-73-8. Melting point: 64–68℃, boiling point: 196℃ (5×133 Pa).

4-Methyldiphenylmethane-3,4-diisocyanate (CAS No. 75790-84-0).

2,4′-Diisocyanatodiphenyl sulfide (CAS No. 75790-87-3).

Diethyldiisocyanatobenzene (CAS No. 134190-37-7).

Also included are 4,4′-diphenylethane diisocyanate, isopropylidenebis(4-isocyanatocyclohexane), etc.