822-06-0

colourless liquid

ChEBI: A diisocyanate compound with the two isocyanates linked by a hexane-1,6-diyl group.

A colorless crystalline solid. Toxic by ingestion and is strongly irritating to skin and eyes. HEXAMETHYLENE DIISOCYANATE(822-06-0) is used to make nylon.

HEXAMETHYLENE DIISOCYANATE reacts with water. Base-catalyzed reactions of this compound with alcohols may be explosively violent in the absence of diluting solvents. This chemical is incompatible with strong bases, amines, acids and strong oxidizers. HEXAMETHYLENE DIISOCYANATE is also incompatible with metal compounds and surface active materials. .

Contact with moisture or temperatures over 399°F may cause polymerization. Soluble in water.

Combustible.

TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Contact with molten substance may cause severe burns to skin and eyes. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

Used to make other chemicals, coat ings, and polyurethane. It is also used as a hardener in automobile and airplane paints.

Combustible material: may burn but does not ignite readily. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapors may travel to source of ignition and flash back. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, includ ing resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medi cal attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. Medical observation is recommended for 24 to 48 hours after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a drug or other inhalation therapy.

UN2281 Hexamethylene diisocyanate, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

May form explosive mixture with air. Isocyanates are highly flammable and reactive with many compounds, even with themselves. Incompatible with oxi dizers (chlorates, nitrates, peroxides, permanganates, per chlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Reaction with moist air, water or alcohols may form amines and insoluble polyureas and react exothermically, releasing toxic, corrosive or flamma ble gases, including carbon dioxide; and, at the same time, may generate a violent release of heat increasing the con centration of fumes in the air. Incompatible with amines, aldehydes, alkali metals, ammonia, carboxylic acids, capro lactum, alkaline materials, glycols, ketones, mercaptans, hydrides, organotin catalysts, phenols, strong acids, strong bases, strong reducing agents such as hydrides, urethanes, ureas. Elevated temperatures or contact with acids, bases, tertiary amines, and acyl-chlorides may cause explosive polymerization. Attacks some plastics, rubber and coatings. Contact with metals may evolve flammable hydrogen gas. May accumulate static electrical charges, and may cause ignition of its vapors. Temperatures above 200℃ can cause polymerization. Attacks copper.

This diisocyanate compound is used in the manufacture of various polyurethane products: elastic and rigid foams, paints, lacquers, adhesives, bin ding agents, synthetic rubbers, and elastomeric fibers.

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).

Hexamethylene diisocyanate (HDI) 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. It 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.

Notclassified

HDI is not readily soluble (low mg l^-1 range) in water. However, upon contact with water, reactivity is rapid with a half-life of 0.23 h at 23 ℃. This nonhomogeneous reaction is expected to produce principally polyureas. In the occupational environment, an aerosol can be formed by nebulization; however, with a vapor pressure of 0.007 hPa, HDI is expected to exist in the ambient atmosphere in its vapor state. As a vapor, HDI is expected to degrade in the atmosphere by reaction with hydroxyl radicals (half-life approximately 2 days). In direct contact with water, its rapid hydrolysis reduces the likelihood for HDI to bioaccumulate in the aquatic compartment or transfer to groundwater. Therefore, the rapid hydrolysis in an aquatic environment and relatively rapid degradation in atmosphere limits the ability of this substance to be bioaccumulative or persistent.

Color Code- Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Before entering confined space where this chemicalmay be present, check to make sure that an explosive con-centration doesnot exist. Hexamethylene diisocyanateshould be stored away from moisture or water. This contactwill causeit to polymerize? andIexplode its container.Hexamethylene diiso-cyanate must be stored to avoid con-tact with amines, carboxylic acids, strong bases, and alco-hols since violent reactions occur. Store in tightly closedcontainers in a cool, well-ventilated area at temperaturesbelow 93℃/200°F.

Toxicity predominantly results from direct interaction of HDI with tissues or macromolecules at the portal of entry. HDI reacts with biologic macromolecules containing nucleophilic –NH, –SH, –OH, or –COOH groups, and these interactions are thought to account for acute irritation to skin and mucus membranes, sensory irritation, and dermal sensitization. Less clear is the etiology of HDI-induced occupational asthma. A number of mechanisms, including immunologic, neurologic, and pharmacologic, have been postulated without a clear resolution. Overall, these mechanisms account for the principal effects associated with HDI that lead to toxicity at the portal of entry with no evidence of primary systemic organ toxicity.

The chronic (long-term) initial threshold screening level (ITSL) for 1,6-hexamethylene diisocyanate (HDI) is 0.2 μg/m3 based on annual averaging time. The short-term ITSL for HDI is 0.3 μg/m3 with an 8-hr averaging time.

Disposal is by chemical incineration of HDIsolution in a combustible solvent.