Hexamethylene diisocyanate

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For other uses of the abbreviation HDI, see HDI (disambiguation).
Hexamethylene diisocyanate
Hexamethylene diisocyanate
Hexamethylene diisocyanate
Names
IUPAC name
1,6-diisocyanatohexane
Other names
HDI
1,6-hexane diisocyanate
Identifiers
822-06-0 YesY
ChEBI CHEBI:53578 YesY
ChemSpider 12637 YesY
Jmol-3D images Image
PubChem 13192
Properties
C8H12N2O2
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
Hazards
Flash point 130–140 °C (Cleveland open cup)
US health exposure limits (NIOSH):
none[1]
TWA 0.005 ppm (0.035 mg/m3) C 0.020 ppm (0.140 mg/m3) [10-minute][1]
N.D.[1]
Related compounds
Related isocyanates
Isophorone diisocyanate
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY verify (what isYesY/N?)
Infobox 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.[2] 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.

Synthesis[edit]

There are two steps to the synthesis of pure HDI:[2]

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

Chemistry[edit]

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

See also[edit]

References[edit]

  1. ^ a b c d e "NIOSH Pocket Guide to Chemical Hazards #0320". National Institute for Occupational Safety and Health (NIOSH). 
  2. ^ a b Randall, David; Lee, Steve (2002). The Polyurethanes Book. New York: Wiley. ISBN 978-0-470-85041-1. 

External links[edit]