Description
2-Hexanone has been used as a solvent for both cellulose- and
resin-based coating systems. In the early 1970s, a number of
workers in the print department of a coated fabrics plant
developed severe peripheral neuropathy from an unknown
cause. In search of an etiological agent, and in the absence of
other neurotoxicants, 2-hexanone was implicated as it was
recently substituted for methyl isobutyl ketone in the
manufacturing process. Similar observations in workers
exposed to 2-hexanone may have resulted in the decline in
production and use in the United States.
Chemical Properties
MNBK is a colorless liquid with an acetonelike odor. The odor threshold is 0.08 ppm.
Chemical Properties
2-Hexanone is a colorless to pale yellow liquid with a sharp odor. It dissolves very easily in
water and is miscible in ethanol, methanol, and benzene. 2-Hexanone evaporates easily into
the air as a vapor. It is stable, flammable, and incompatible with oxidizing agents, strong bases,
and reducing agents. 2-Hexanone is a waste product of wood pulping, coal gasifi cation, and
oil shale operations. Formerly, 2-hexanone was in use as a paint and paint thinner with other
chemical substances, and to dissolve oils and waxes.and is used as a solvent and organic syn-
thesis intermediates. However, the industrial uses of 2-hexanone is now very much restricted.
Physical properties
Clear, colorless to pale yellow, flammable liquid with an odor resembling acetone and 2-butanone.
Nagata and Takeuchi (1990) reported an odor threshold concentration of 24 ppb
v. Amoore and
Hautala (1983) reported odor threshold concentrations of 250 μg/L and 76 ppb
v in water and air,
respectively.
Uses
As industrial solvents for adhesives,
lacquers, paint removers, and acrylic coatings
Uses
Methyl butyl ketone (MBK) is used as asolvent for nitrocellulose, resins, lacquers,oils, fats, and waxes.
Uses
2-Hexanone is used in various organic chemical syntheses. It is used in the synthesis of (+/-)-monomorine. It is also used in the preparation of alcohols by transfer hydrogenation of ketones.
Definition
ChEBI: 2-Oxohexane is a ketone.
Production Methods
MnBK can be produced by a reaction between acetic acid and ethylene under pressure MnBK can be produced by a reaction between acetic acid and ethylene under pressure.
General Description
A clear colorless liquid. Flash point 95°F. Less dense than water. Vapors heavier than air.
Air & Water Reactions
Highly flammable. Slightly soluble in water.
Reactivity Profile
2-Hexanone is incompatible with oxidizing agents. 2-Hexanone may also react with strong bases and reducing agents.
Hazard
Flammable, moderate fire risk, explosive limits 1.2–8% in air. Irritant to eyes and
mucous membranes, narcotic in high concentration,
absorbed by skin. Causes peripheral neuropathy and
testicular damage.
Health Hazard
Inhalation of high concentrations of vapor may result in narcosis; peripheral neuropathy may develop. Ingestion of large amounts may cause some systemic injury. Contact with eyes causes mild to moderate irritation. Liquid irritates skin; prolonged or repeated contact may cause defatting of the skin with resultant dermatitis.
Health Hazard
Chronic exposure to MBK via inhalationor skin absorption can cause disordersof the peripheral nervous system andneuropathic diseases. The symptoms inhumans, depending on the severity ofexposure, were parasthesias in the handsor feet, muscle weaknesses, weakness inankles and hand, and difficulty in grasping heavy objects. Animal studies indicatethat prolonged exposure to this compoundat a concentration of 200–1300 ppm for4–12 weeks can result in neuropathy.Neurotoxicity is attributed to its primarymetabolite, 2,5-hexanedione. Improvementin conditions can occur slowly over monthsafter cessation of exposure. Acute exposureto high concentrations, 1000 ppm, for severalminutes can cause irritation of the eyes andnose in humans. Inhalation to 20,000 ppmfor 30 minutes caused narcosis in guineapigs and prolonged exposure for 70 minuteswas lethal. The acute oral toxicity in ratswas low.
LD50 value, oral (rats): 2600 mg/kg.
Fire Hazard
2-Hexanone is flammable.
Potential Exposure
The material is used as a solvent
First aid
If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 min, 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, including 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 medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.
Environmental Fate
Biological. Using the BOD technique to measure biodegradation, the mean 5-d BOD value (mM
BOD/mM 2-hexanone) and ThOD were 5.22 and 61.4%, respectively (Vaishnav et al., 1987).
Photolytic. A second-order photooxidation rate constant of 8.97 x 10
-12 cm
3/molecule?sec for the
reaction of 2-hexanone and OH radicals in the atmosphere at 299 K was reported by Atkinson
(1985).
Chemical/Physical. 2-Hexanone will not hydrolyze because it has no hydrolyzable functional
group (Kollig, 1995).
storage
2-Hexanone should be kept stored in a tightly closed container, in a cool, dry place, away
from sources of ignition.
Shipping
UN1224 Ketones, liquid, n.o.s., Hazard Class: 3;
Labels: 3-Flammable liquid, Technical Name Required
Toxicity evaluation
Regardless of the route of exposure, both human and animal
studies indicate that the nervous system is the target organ of
2-hexanone toxicity with its metabolite, 2,5-hexanedione,
serving as the neurotoxic agent. 2,5-Hexanedione binds covalently
to axonal components of the nerve tissue. In vitro studies
have shown that this metabolite reacts with the nucleophilic
lysine 3-amino groups to ultimately form 2,5-dimethylpyrrole
adducts with neurofilaments. Neurofilament aggregates concentrate
in the distal subterminal axon, resulting in axonal
swelling, or distal axonopathy, just proximal to the nodes of
Ranvier. These reactions may lead to the manifestation of
peripheral neuropathy.
Incompatibilities
Violent reaction with oxidizers. May form unstable peroxides. Attacks plastics.
Waste Disposal
Dissolve or mix the
material with a combustible solvent and burn in a chemical
incinerator equipped with an afterburner and scrubber.
All federal, state, and local environmental regulations
must be observed.
Precautions
Occupational workers should be careful when using and handling 2-hexanone. Workers
should wash thoroughly after handling the chemical substance. Workers should avoid contact of 2-hexanone with the eyes, skin, and clothing and also avoid contact with heat,
sparks, and flame.
