Hexamethylene diisocyanate

Hexamethylene diisocyanate

Names
IUPAC name 1,6-diisocyanatohexane
Other names HDI 1,6-hexane diisocyanate
Identifiers
CAS Registry Number	822-06-0 Y
ChEBI	CHEBI:53578 Y
ChemSpider	12637 Y
InChI InChI=1S/C8H12N2O2/c11-7-9-5-3-1-2-4-6-10-8-12/h1-6H2 Y Key: RRAMGCGOFNQTLD-UHFFFAOYSA-N Y InChI=1/C8H12N2O2/c11-7-9-5-3-1-2-4-6-10-8-12/h1-6H2 Key: RRAMGCGOFNQTLD-UHFFFAOYAI
Jmol-3D images	Image
PubChem	13192
SMILES O=C=N\CCCCCC/N=C=O
Properties
Chemical formula	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):
PEL (Permissible)	none[1]
REL (Recommended)	TWA 0.005 ppm (0.035 mg/m3) C 0.020 ppm (0.140 mg/m3) [10-minute][1]
IDLH (Immediate danger)	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)
Y verify (what is: Y/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

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

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

See also

• Methylene diphenyl diisocyanate
• Toluene diisocyanate

References

1. ↑ 1.0 1.1 1.2 1.3 1.4 "NIOSH Pocket Guide to Chemical Hazards #0320". National Institute for Occupational Safety and Health (NIOSH). 
2. ↑ 2.0 2.1 Randall, David; Lee, Steve (2002). The Polyurethanes Book. New York: Wiley. ISBN 978-0-470-85041-1. 

External links

• NIOSH Safety and Health Topic: Isocyanates, from the website of the National Institute for Occupational Safety and Health (NIOSH)
• NIOSH Pocket Guide to Chemical Hazards - Hexamethylene diisocyanate