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Hexamethylene diisocyanate is a highly reactive aliphatic diisocyanate used as a key building block in polyurethane coatings and resin systems.
Hexamethylene diisocyanate improves durability, chemical resistance, flexibility, and weathering performance in high-performance coatings.
Hexamethylene diisocyanate is used in the chemical synthesis of aliphatic polyisocyanates and polyurethanes, such as aqueous dispersible polyurethane polymers (PUD) showing exceptional weathering resistance and flexibility.
CAS number: 822-06-0
EC number: 212-485-8
Molecular Formula: C8H12N2O2
Molecular weight: 168.19 g/mol
Synonyms: 1,6-Diisocyanatohexane, Hexamethylene diisocyanate, 822-06-0, HMDI, 1,6-Hexamethylene diisocyanate, Hexane, 1,6-diisocyanato-, Hexane 1,6-diisocyanate, 1,6-Hexylene diisocyanate, Hexamethylene-1,6-diisocyanate, hexamethylenediisocyanate, Isocyanic acid, hexamethylene ester, 1,6-Hexanediol diisocyanate, TL 78, Szesciometylenodwuizocyjanian, Metyleno-bis-fenyloizocyjanian, 1,6-hexane diisocyanate, Hexamethylendiisokyanat, DTXSID4024143, Desmodur H, Isocyanic acid, diester with 1,6-hexanediol, GMDI, 0I70A3I1UF, CHEBI:53578, NSC-11687, DTXCID004143, HDI cpd, RefChem:146078, 212-485-8, 618-151-1, HDI-IC, HDI, MFCD00002047, NSC 11687, Hexamethylene diisocyanate, 1,6-, 1,6-diisocyanato-hexane, Hexamethylene 1,6-diisocyanate, Hexamethylene-1,6-diisocyanate [Diisocyanates], 53895-37-7, CAS-822-06-0, Hexamethylendiisokyanat [Czech], HSDB 6134, EINECS 212-485-8, UN2281, hexamethylene di-isocyanate, HEXAMETHYLENE-1,6-DIISOCYANATE (DIISOCYANATES), Szesciometylenodwuizocyjanian [Polish], Metyleno-bis-fenyloizocyjanian [Polish], BRN 0956709, UNII-0I70A3I1UF, AI3-28285, CCRIS 8431, Hexane,6-diisocyanato-, 1,6-diisocyanato hexane, hexane-1,6-diisocyanate, WLN: OCN6NCO, Epitope ID:115018, EC 212-485-8, Isocyanic acid,6-hexanediol, SCHEMBL15038, 1,6-diisocyanatohexamethylene, OCN-(CH2)6-NCO, 88357-62-4, 1,6-hexamethylene-diisocyanate, 1,6-Diisocyanatohexane, 98%, GTPL6291, SCHEMBL1070434, 1,6-hexamethylene di-isocyanate, CHEMBL1896533, HEXANE,1,6-DIISOCYANATE, SCHEMBL28481235, NSC11687, Tox21_202206, Tox21_300161, MSK001029, SBB069499, STL301890, AKOS000120355, Hexamethylene diisocyanate [HSDB], NCGC00164175-01, NCGC00164175-02, NCGC00164175-03, NCGC00254122-01, NCGC00259755-01, PD051392, S 90, S-90, DB-225988, H0324, NS00008899, EN300-20358, Hexamethylene diisocyanate [UN2281] [Poison], F145100, Q418197, Hexamethylene diisocyanate, purum, >=98.0% (GC), Hexamethylene diisocyanate, puriss., >=99.0% (GC), InChI=1/C8H12N2O2/c11-7-9-5-3-1-2-4-6-10-8-12/h1-6H
Hexamethylene diisocyanate is an aliphatic diisocyanate mainly used as a reactive building block in polyurethane systems.
Hexamethylene diisocyanate provides high durability, chemical resistance, weather resistance, and strong film-forming performance in coatings and industrial resin systems.
Hexamethylene diisocyanate is especially important in high-performance polyurethane coatings where color stability, flexibility, and long-term outdoor resistance are required.
Hexamethylene diisocyanate is the organic compound with the formula (CH2)6(NCO)2.
Hexamethylene diisocyanate is classified as an diisocyanate.
Hexamethylene diisocyanate is a colorless liquid.
Hexamethylene diisocyanate has sometimes been called HMDI but this not usually done to avoid confusion with Hydrogenated MDI.
Hexamethylene diisocyanate is a colorless liquid with a high boiling point.
Belongs to the class of polyurethane precursors and is used as an intermediate in the production of polyurethane foams.
Hexamethylene diisocyanate may act to form esters with various alcohols and amines, being chiral compounds they can be analyzed by electrochemical impedance spectroscopy.
Hexamethylene diisocyanate is also used in the production of coatings, adhesives, and sealants.
Hexamethylene diisocyanate is a key aliphatic diisocyanate compound in the chemical industry.
Hexamethylene diisocyanate stands out for its excellent resistance to UV radiation, abrasion, and long-lasting gloss retention.
As a result, Hexamethylene diisocyanate serves as a core raw material in polyurethane coatings, adhesives, and elastomers.
This article delves into its chemical profile, production processes, and industrial applications.
Additionally, Hexamethylene diisocyanate provides updates on global market trends for HDI.
Hexamethylene diisocyanate is also known as monomeric aliphatic diisocyanate.
Hexamethylene diisocyanate is used in the chemical synthesis of aliphatic polyisocyanates and polyurethanes, such as aqueous dispersible polyurethane polymers (PUD) showing exceptional weathering resistance and flexibility.
Applications of Hexamethylene Diisocyanate:
Hexamethylene diisocyanate is an aliphatic diisocyanate monomer typically used to produce oligomers and prepolymers that when combined with a polyol produce light-stable polyurethane.
Highly reactive 1,6-Hexamethylene diisocyanate (HMDI) was used to synthesize lactic acid polymers from oligomers by the addition of 2,2′-bis(2-oxazoline) (BOX) as chain extenders.
Self-healing ability was rendered to polyurethane elastomer by synthesizing alkoxyamine-based diol and reacting it with tri-functional homopolymer of HMDI and polyethylene glycol (PEG).
Plastic optical fiber (POF) was prepared by the bulk homopolymerization of HMDI catalyzed by Tin(II)-2 ethylhexanoate (SnOct).
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.
Hexamethylene diisocyanate is also sold oligomerized as the trimer or biuret which are used in automotive refinish coatings.
Although more viscous in these forms, Hexamethylene diisocyanate reduces the volatility and toxicity.
Hexamethylene diisocyanate is also used as an activator in process of in situ polymerization of caprolactam i.e. cast nylon process.
Hexamethylene diisocyanate is also used bisoxazolidine synthesis as the hydroxyl group on the molecule allows for further reaction with Hexamethylene diisocyanate.
Industrial Applications:
In Polyurethane Coatings and Paints:
The primary application of Hexamethylene diisocyanate is as a curing agent in two-component polyurethane coating systems.
Hexamethylene diisocyanate-based coatings offer high mechanical durability, chemical resistance, UV protection, and long-term color stability.
The automotive sector represents the largest share (about 66% of demand), including original equipment manufacturer (OEM) paints and refinishing.
Additionally, Hexamethylene diisocyanate is used in aerospace, marine, infrastructure, and other industrial coatings that demand rigorous performance standards.
Adhesives and Elastomers:
Hexamethylene diisocyanate is employed in the production of thermoplastic polyurethane (TPU) and specialized adhesives.
These products provide exceptional flexibility, load-bearing capacity, and chemical durability, making them ideal for various engineering applications.
Specialized Applications:
Certain medical and niche sectors also utilize Hexamethylene diisocyanate.
Hexamethylene diisocyanate finds use in dental materials, contact lenses, and medical adsorbents.
However, these applications require stringent quality control to minimize risks from unreacted monomers.
Uses of Hexamethylene Diisocyanate:
Hexamethylene diisocyanate is used in polyurethane coatings, automotive refinishes, aircraft coatings, industrial paints, elastomers, adhesives, sealants, textile treatments, leather finishes, and crosslinked polymer systems.
Hexamethylene diisocyanate is also used to produce HDI-based biurets, isocyanurates, and prepolymers for safer and more controlled coating applications.
Hexamethylene diisocyanate is one of the most common aliphatic disocyanates.
Hexamethylene diisocyanate is a monomer used in the production of polyurethane foams and exceptionally high-quality coatings, and is found in some industrial paints and spray painting operations.
Hexamethylene diisocyanate is a compound which reacts readily with water and alcohols (Von Burg 1993).
Hexamethylene diisocyanate has a vapor pressure of 0.05 mm Hg at room temperature, but can be present in aerosol form allowing a potentially higher exposure to individuals.
The Hexamethylene diisocyanate-BT trimer is often present for similar industrial uses.
Hexamethylene diisocyanate would be expected to have a lower vapor pressure; however, the aerosol form can also be present, allowing potentially higher exposure of HDI-BT to individuals.
Hexamethylene diisocyanate reacts slowly with water to form carbon dioxide.
The base-catalyzed reaction of Hexamethylene diisocyanate with alcohols should be carried out in inert solvents; the reaction may occur with explosive violence in the absence of solvents.
Hexamethylene diisocyanate is used as a cross-linking agent to manufacture dental materials, contact lenses, medical adsorbents, and polyurethanes; may be released during the spraying of polyurethane paints.
Hexamethylene diisocyanate is commonly used as a hardener in polyurethane automobile paints.
Occupational asthma reported in a spray painter.
Hexamethylene diisocyanate is used to make polyisocyanate products for curing agents in polyurethane paint systems (automobile, marine, industrial maintenance, and other high-performance coatings).
Industry Uses:
Paint additives and coating additives not described by other categories
Monomers
Intermediates
Consumer Uses:
Monomers
Chemical Profile and Basic Properties of Hexamethylene Diisocyanate:
Hexamethylene diisocyanate is an important aliphatic organic compound in the chemical sector.
With the chemical formula C₈H₁₂N₂O₂ and CAS number 822-06-0.
Hexamethylene diisocyanate is widely recognized as a primary feedstock for producing high-performance polyurethane (PUR) resins.
Under standard conditions, Hexamethylene diisocyanate appears as a clear, colorless to slightly yellow liquid with a pungent characteristic odor.
Hexamethylene diisocyanate's molecular weight is 168.2 g/mol.
The boiling point is approximately 213°C at atmospheric pressure, and its vapor pressure is only 0.05 mmHg at 25°C, indicating low volatility.
What makes Hexamethylene diisocyanate particularly noteworthy is its ability to form mechanically durable coatings.
This enhances resistance to abrasion, chemicals, gloss retention, and UV degradation.
Consequently, Hexamethylene diisocyanate is increasingly viewed as a critical link in the value chain for the coatings, adhesives, and industrial elastomers industries.
Preparation of Hexamethylene Diisocyanate:
Hexamethylene diisocyanate is prepared by the phosgenation of hexamethylenediamine (section lO.2.2(b)):
H2N-(CH2)6-NH2--COCl2-->OCN-(CH2)6-NCO
Hexamethylene diisocyanate is a liquid with a volatility of the same order as that of tolylene diisocyanate.
Hexamethylene diisocyanate is respiratory irritant and also has powerful effects on the skin and eyes.
Hexamethylene diisocyanate was one of the first diisocyanates utilized for making polyurethanes, being used to prepare fibres and moulding compounds.
These applications are no longer of importance but Hexamethylene diisocyanate now finds use mainly in coatings which are more light stable than those based on aromatic isocyanates.
Production Process of Hexamethylene Diisocyanate:
Most commercial Hexamethylene diisocyanate is produced via the phosgenation method using hexamethylenediamine (HDA) as the starting material.
The process involves two main stages:
Salt Formation:
HDA is dissolved in an organic solvent and then reacted with HCl to form diammonium chloride salt.
Phosgenation:
The salt solution is reacted with phosgene gas (COCl₂) at high temperatures, yielding Hexamethylene diisocyanate along with HCl as a byproduct.
Given that phosgene is highly toxic, this process requires a fully enclosed production system, strict adherence to safety standards, and significant capital investment.
These barriers result in the Hexamethylene diisocyanate market being dominated by a few major producers, such as Covestro, Vencorex, and Tosoh, which account for over 70% of the global market share.
Synthesis of Hexamethylene Diisocyanate:
Compared to other commercial diisocyanates, Hexamethylene diisocyanate is produced in relatively small quantities, accounting for (with isophorone diisocyanate) only 3.4% of the global diisocyanate market in the year 2000.
Hexamethylene diisocyanate is produced by phosgenation of hexamethylene diamine.
Stability and Reactivity of Hexamethylene Diisocyanate:
Chemical stability:
Stable under dry, controlled storage conditions.
Reactivity:
Reacts with water.
Alcohols.
Amines.
Acids.
Strong bases.
Active hydrogen compounds.
Conditions to avoid:
Moisture.
Excessive heat.
Open flames.
Uncontrolled contamination.
Incompatible materials:
Water.
Alcohols.
Amines.
Strong bases.
Acids.
Oxidizing agents.
Organometallic catalysts.
Hazardous decomposition products:
Carbon oxides.
Nitrogen oxides.
Hydrogen cyanide.
Isocyanate vapors may form under fire or thermal decomposition conditions.
Handling and Storage of Hexamethylene Diisocyanate:
Handling:
Use only with adequate ventilation.
Avoid inhalation.
Skin contact.
Eye contact.
Storage:
Store in tightly closed containers in a cool, dry, well-ventilated area.
Temperature:
Protect from excessive heat.
Moisture.
Precautions:
Keep away from water.
Alcohols.
Amines.
Acids.
Strong bases.
First Aid Measures of Hexamethylene Diisocyanate:
Inhalation:
Move the person to fresh air.
Seek medical attention if breathing difficulty.
Coughing.
Irritation occurs.
Skin contact:
Remove contaminated clothing.
Wash skin thoroughly with soap and water.
Eye contact:
Rinse carefully with water for at least 15 minutes.
Seek medical attention.
Ingestion:
Do not induce vomiting.
Seek immediate medical attention.
Firefighting Measures of Hexamethylene Diisocyanate:
Extinguishing media:
Foam.
Dry chemical.
Carbon dioxide.
Water spray.
Fire hazards:
Heating may produce toxic fumes.
Pressure buildup in containers.
Protection:
Firefighters should use self-contained breathing apparatus.
Full protective clothing.
Accidental Release Measures of Hexamethylene Diisocyanate:
Containment:
Stop the leak if safe.
Prevent entry into drains.
Waterways.
Cleanup:
Absorb with inert material.
Place in suitable chemical waste containers.
Precautions:
Ensure strong ventilation.
Avoid direct contact with the material.
Exposure Controls / Personal Protective of Hexamethylene Diisocyanate:
Engineering controls:
Use local exhaust ventilation.
Closed handling systems.
Respiratory protection:
Use suitable respiratory protection when ventilation is insufficient.
Eye protection:
Wear chemical safety goggles.
Face protection.
Skin protection:
Wear chemical-resistant gloves.
Protective clothing.
Hygiene measures:
Wash thoroughly after handling.
Remove contaminated clothing before reuse.
Identifiers of Hexamethylene Diisocyanate:
CAS No.: 822-06-0
CBNumber: CB4255051
Molecular Formula: C8H12N2O2
Molecular Weight: 168.19
MDL Number: MFCD00002047
Linear Formula: OCN(CH2)6NCO
CAS Number: 822-06-0
Molecular Weight: 168.19
UNSPSC Code: 12352118
EC Index Number: 212-485-8
NACRES: NA.22
MDL number: MFCD00002047
Product Number: H0324
Purity / Analysis Method : >98.0%(GC)
Molecular Formula / Molecular Weight: C8H12N2O2 = 168.20
Physical State (20 deg.C): Liquid
Storage Temperature : Refrigerated (0-10°C)
Store Under Inert Gas: Store under inert gas
CAS RN: 822-06-0
Reaxys Registry Number: 956709
PubChem Substance ID: 87570744
SDBS (AIST Spectral DB): 2188
MDL Number: MFCD00002047
Chemical name: Hexamethylene diisocyanate
Common abbreviation: HDI
CAS number: 822-06-0
EC number: 212-485-8
Molecular formula: C₈H₁₂N₂O₂
Molecular weight: 168.19 g/mol
Linear formula: OCN(CH₂)₆NCO
PubChem CID: 13192
Linear Formula: OCN(CH2)6NCO
CAS Number: 822-06-0
Molecular Weight: 168.19
EC Number: 212-485-8
CAS Number: 822-06-0
ChEBI: CHEBI:53578
ChemSpider: 12637
ECHA InfoCard: 100.011.350
IUPHAR/BPS: 6291
PubChem CID: 13192
UNII: 0I70A3I1UF
CompTox Dashboard (EPA): DTXSID4024143
InChI: InChI=1S/C8H12N2O2/c11-7-9-5-3-1-2-4-6-10-8-12/h1-6H2
Key: RRAMGCGOFNQTLD-UHFFFAOYSA-N
InChI=1/C8H12N2O2/c11-7-9-5-3-1-2-4-6-10-8-12/h1-6H2
Key: RRAMGCGOFNQTLD-UHFFFAOYAI
SMILES: O=C=NCCCCCC/N=C=O
Properties of Hexamethylene Diisocyanate:
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
Appearance: Colorless to pale yellow liquid
Odor: Sharp, irritating odor
Chemical class: Aliphatic diisocyanate
Boiling Point: 255 °C
Flash point: 138 °C
Specific Gravity (20/20): 1.05
Refractive Index: 1.45
Solubility (soluble in): Benzene, Toluene, Acetone
Molecular Weight: 168.19 g/mol
XLogP3-AA: 3.2
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 4
Rotatable Bond Count: 7
Exact Mass: 168.089877630 Da
Monoisotopic Mass: 168.089877630 Da
Topological Polar Surface Area: 58.9 Ų
Heavy Atom Count: 12
Complexity: 169
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes
Melting point: -55°C
Boiling point: 82-85 °C/0.1 mmHg
Density: 1.047 g/mL at 20 °C (lit.) 1.047 g/mL at 20 °C
vapor pressure: 0.05 mm Hg ( 25 °C)
refractive index: n20/D 1.453
Flash point: 248 °F
storage temp.: Store below +30°C.
form: Liquid
Specific Gravity: 1.05
color: Clear colorless to slightly yellow
explosive limit: 0.9-9.5%(V)
Viscosity: 2.29mm2/s
Water Solubility: Reacts
Specifications of Hexamethylene Diisocyanate:
Appearance: Colorless to Almost colorless clear liquid
Purity(GC): min. 98.0 %
NMR: confirm to structure
Related compounds of Hexamethylene Diisocyanate:
Related isocyanates:
Isophorone diisocyanate
Names of Hexamethylene Diisocyanate:
Preferred IUPAC name:
1,6-Diisocyanatohexane
Other names:
HDI
1,6-hexane diisocyanate
