Hexamethylene diisocyanate

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Hexamethylene diisocyanate
Hexamethylene diisocyanate
Hexamethylene diisocyanate
IUPAC name
Other names
1,6-hexane diisocyanate
3D model (JSmol)
ECHA InfoCard 100.011.350 Edit this at Wikidata
Molar mass 168.2 g/mol
Appearance Colourless liquid
Odor sharp, pungent[1]
Density 1.047 g/cm3, liquid
Melting point −67 °C (−89 °F; 206 K)
Boiling point 255 °C (491 °F; 528 K)
Vapor pressure 0.05 mmHg (25 °C)[1]
Viscosity 3 cP at 25 °C
Flash point 130–140 °C (Cleveland open cup)
NIOSH (US health exposure limits):
PEL (Permissible)
REL (Recommended)
TWA 0.005 ppm (0.035 mg/m3) C 0.020 ppm (0.140 mg/m3) [10-minute][1]
IDLH (Immediate danger)
Related compounds
Related isocyanates
Isophorone diisocyanate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Hexamethylene diisocyanate (HDI) is the organic compound with the formula (CH2)6(NCO)2. It is classified as an diisocyanate. It is a colorless liquid.[2]


Compared to other commercial diisocyanates, HDI is produced in relatively small quantities, accounting for (with isophorone diisocyanate) only 3.4% of the global diisocyanate market in the year 2000.[3] It is produced by phosgenation of hexamethylene diamine.


Aliphatic diisocyanates are used in specialty applications, such as enamel coatings which are resistant to abrasion and degradation by ultraviolet light. These properties are particularly desirable in, for instance, the exterior paint applied to aircraft and vessels. HDI is also sold oligomerized as the trimer or biuret. Although more viscous in these forms, it reduces the volatility and toxicity. At least 3 companies sell material in this form commercially.

See also[edit]


  1. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0320". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ Christian Six, Frank Richter (2005). "Isocyanates, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a14_611.CS1 maint: uses authors parameter (link)
  3. ^ Randall, David; Lee, Steve (2002). The Polyurethanes Book. New York: Wiley. ISBN 978-0-470-85041-1.

External links[edit]