Hexamethylene diisocyanate

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Hexamethylene diisocyanate
Hexamethylene diisocyanate
Hexamethylene diisocyanate
Names
Preferred IUPAC name
1,6-Diisocyanatohexane
Other names
HDI
1,6-hexane diisocyanate
Identifiers
3D model (
JSmol
)
ChEBI
ChemSpider
ECHA InfoCard
 100.011.350 Edit this at Wikidata
IUPHAR/BPS
UNII
  • InChI=1S/C8H12N2O2/c11-7-9-5-3-1-2-4-6-10-8-12/h1-6H2 checkY
    Key: RRAMGCGOFNQTLD-UHFFFAOYSA-N checkY
  • InChI=1/C8H12N2O2/c11-7-9-5-3-1-2-4-6-10-8-12/h1-6H2
    Key: RRAMGCGOFNQTLD-UHFFFAOYAI
  • O=C=N\CCCCCC/N=C=O
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 (266–284 °F; 403–413 K) (Cleveland open cup)
NIOSH (US health exposure limits):
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 otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

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] It has sometimes been called HMDI[3] but this not usually done to avoid confusion with Hydrogenated MDI.

Synthesis

Compared to other commercial diisocyanates, HDI is produced in relatively small quantities, accounting for (with

hexamethylene diamine
.

Applications

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 which are used in automotive refinish coatings.[5][6] Although more viscous in these forms, it reduces the volatility and toxicity. At least 3 companies sell material in this form commercially. It is also used as an activator in process of in situ polymerization of caprolactam i.e. cast nylon process. HDI is also used bisoxazolidine synthesis as the hydroxyl group on the molecule allows for further reaction with hexamethylene diisocyanate.[7][8]

Toxicity

HDI is considered toxic, and its pulmonary toxicity has been studied as well as its oligomers.[9][10][11][12]

See also

References

  1. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0320". National Institute for Occupational Safety and Health (NIOSH).
  2. ISBN 3-527-30673-0
    .
  3. ^ PubChem. "Hexamethylene diisocyanate". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-08-04.
  4. ISBN 978-0-470-85041-1
    .
  5. ^ Jeffries, Michael; Gambino, Charles; Pierce, Joe. "Acrylate Monomer Free/VOC Compliant Ultraviolet-A Radiation Curable Technology for Automotive Refinish Clear Coat" (PDF).
  6. ISSN 0300-9440
    .
  7. ^ "2-[2-(propan-2-yl)-1,3-oxazolidin-3-yl]ethanol - Registration Dossier - ECHA". echa.europa.eu. Retrieved 2018-11-14.
  8. S2CID 93574741
    .
  9. PMID 12729715
    .
  10. PMID 11053554
    .
  11. S2CID 13505170.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  12. PMID 12204825
    .

External links
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