Lysine Diisocyanate

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Several diisocyanates are derived from lysine [structural formula NH2(CH2)4CH(NH2)COOH], and the term “lysine diisocyanate (LDI)” is used, which seems somewhat confusing.

(1), (S)-2,6-Diisocyanatohexanoic acid, L-lysine diisocyanate.

Structural formula: OCN(CH₂)₄CH(NCO)COOH. Molecular formula: C₈H₁₀N₂O₄, molecular weight: 198.18. CAS number: 34050-00-5.

(2), 2,6-Hexanoic acid methyl ester diisocyanate, also known as lysine methyl ester diisocyanate.

Structural formula: OCN(CH₂)₄CH(NCO)COOCH₃, molecular formula: C₉H₁₂N₂O₄, molecular weight: 212.20. CAS number: 4460-02-0, EINECS number: 224-712-8.

Appearance: Colorless to light yellow liquid, relative density approximately 1.157, refractive index (20℃) 1.4565, boiling point 123℃ (60Pa).

(3), 2,6-Hexanoic acid ethyl ester diisocyanate, also known as lysine ethyl ester diisocyanate, or simply lysine diisocyanate.

Structural formula: OCN(CH₂)₄CH(NCO)COOCH₂CH₃, molecular formula: C₁₀H₁₄N₂O₄, molecular weight: 226.2. CAS number: 45172-15-4. Appearance: Reddish-brown liquid.

Lysine diisocyanate is an aliphatic diisocyanate. Polyurethanes made from it are resistant to yellowing and have strong adhesion, making them suitable for applications such as polyurethane coatings.