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Hexamethylene diisocyanate

For other uses of the abbreviation HDI, see HDI (disambiguation).
Hexamethylene diisocyanate
IUPAC name 1,6-diisocyanatohexane
Other names HDI
1,6-hexane diisocyanate
CAS number 822-06-0
Molecular formula C8H12N2O2
Molar mass 168.2 g/mol
Appearance Colourless liquid
Density 1.047 g/cm3, liquid
Melting point

-67 °C (206 K)

Boiling point

255 °C (528 K)

Viscosity 3 mPa.s at 25 °C
Flash point 130–140 °C (Cleveland open cup)
Related Compounds
Related isocyanates Isophorone diisocyanate
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Hexamethylene diisocyanate (HDI) is an organic compound in the class known as isocyanates. More specifically, it is an aliphatic diisocyanate. It is produced in relatively small quantities, accounting for (with isophorone diisocyanate) only 3.4% of the global diisocyanate market in the year 2000.[1] Aliphatic diisocyanates are used in special applications, such as enamel coatings which are resistant to abrasion and degradation from ultraviolet light. These properties are particularly desirable in, for instance, the exterior paint applied to aircraft.



There are two steps to the synthesis of pure HDI:[1]

  • Phosgenation: Reaction of hexamethylene diamine with phosgene to form crude HDI
  • Purification: Distillation of crude HDI to extract pure HDI


HDI is a symmetrical molecule and thus has two isocyanate groups of equal reactivity.

See also


  1. ^ a b Randall, David; Lee, Steve (2002). The Polyurethanes Book. New York: Wiley. ISBN 978-0-470-85041-1. 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Hexamethylene_diisocyanate". A list of authors is available in Wikipedia.
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