Hexane Chemical Properties
- Melting point:
- -95 °C
- Boiling point:
- 68.95 °C(lit.)
- 0.659 g/mL at 25 °C(lit.)
- vapor density
- 3.5 (vs air)
- vapor pressure
- 40 mm Hg ( 20 °C)
- refractive index
- Flash point:
- 30 °F
- storage temp.
- Store at RT.
- Very soluble in ethanol, ethyl ether and chloroform.
- >14 (Schwarzenbach et al., 1993)
- Specific Gravity
- 0.660 (20/4℃)
- Relative polarity
- Mild gasoline-like odor detectable at 65 to 248 ppm
- Odor Threshold
- explosive limit
- Water Solubility
- λ: 200 nm Amax: ≤0.70
λ: 225 nm Amax: ≤0.10
λ: 250 nm Amax: ≤0.01
- Henry's Law Constant
- 0.238, 0.413, 0.883, 0.768, and 1.56 at 10, 15, 20, 25, and 30 °C, respectively (EPICS, Ashworth et al., 1988)
- Exposure limits
- TLV-TWA 50 ppm (～175 mg/m3) (ACGIH), 500 ppm (～1750 mg/m3) (OSHA); IDLH 5000 ppm (NIOSH).
- Stable. Incompatible with oxidizing agents, chlorine, fluorine, magnesium perchlorate. Highly flammable. Readily forms explosive mixtures with air. Note low flash point.
- CAS DataBase Reference
- 110-54-3(CAS DataBase Reference)
- NIST Chemistry Reference
- EPA Substance Registry System
- Hexane (110-54-3)
- Hazard Codes
- Risk Statements
- Safety Statements
- UN 3295 3/PG 2
- WGK Germany
- Autoignition Temperature
- 225 °C
- HS Code
- Hazardous Substances Data
- 110-54-3(Hazardous Substances Data)
- LC50 (4 hr) in mice by inhalation: 48000 ppm; LD50 orally in rats: 32.0 g/kg (Couri, Milks)
Hexane Usage And Synthesis
n-Hexane is a highly flammable liquid, usually isolated from crude oil, and has extensive industrial applications as a solvent in adhesive bandage factories and other industries. It is highly toxic, triggering several adverse health effects, i.e., nausea, skin irritation, dizzi- ness, numbness of limbs, CNS depression, vertigo, and respiratory tract irritation to ani- mals and humans. Occupational exposure of industrial workers has demonstrated motor polyneuropathy. Workers associated with long-term glue sniffi ng showed adverse effects in the form of degeneration of axons and nerve terminals.
n-Hexane is a highly flammable, colorless, volatile liquid with a gasoline-like odor. The water/odor threshold is 0.0064 mg/L and the air/odor threshold is 230 875 milligram per cubic meter.
Clear, colorless, very flammable liquid with a faint, gasoline-like odor. An odor threshold concentration of 1.5 ppmv was reported by Nagata and Takeuchi (1990).
n-Hexane is a chief constituent of petroleumether, gasoline, and rubber solvent. It is usedas a solvent for adhesives, vegetable oils,and in organic analysis, and for denaturingalcohol.
Suitable for HPLC, spectrophotometry, environmental testing
Determining refractive index of minerals; filling for thermometers instead of mercury, usually with a blue or red dye; extraction solvent for oilseed processing.
ChEBI: An unbranched alkane containing six carbon atoms.
A liquid alkane obtained from the light fraction of crude oil. The principal use of hexane is in gasoline and as a solvent.
Clear colorless liquids with a petroleum-like odor. Flash points -9°F. Less dense than water and insoluble in water. Vapors heavier than air. Used as a solvent, paint thinner, and chemical reaction medium.
Air & Water Reactions
Highly flammable. Insoluble in water.
HEXANE may be sensitive to light. Hexane may also be sensitive to prolonged exposure to heat. Hexane can react vigorously with oxidizing materials. This would include compounds such as liquid chlorine, concentrated O2, sodium hypochlorite and calcium hypochlorite. Hexane is also incompatible with dinitrogen tetraoxide. Hexane will attack some forms of plastics, rubber and coatings. .
Flammable, dangerous fire risk.
Hexane and related aliphatic hydrocarbons exhibit only slight acute toxicity by all routes of exposure. The liquid may cause irritation upon contact with skin or eyes. Hexane vapor (and the vapor of other volatile hydrocarbons) at high concentrations (>1000 ppm) is a narcotic, and inhalation may result in lightheadedness, giddiness, nausea, and headache. Ingestion of hexane or other hydrocarbons may lead to aspiration of the substance into the lungs, causing pneumonia. Prolonged skin exposure may cause irritation due to the ability of these solvents to remove fats from the skin. Hexane is regarded as a substance with good warning properties. Chronic exposure to hexane or other aliphatic hydrocarbons may cause central nervous system toxicity. Hexane has not been found to be a carcinogen or reproductive toxin in humans.
INHALATION causes irritation of respiratory tract, cough, mild depression, cardiac arrhythmias. ASPIRATION causes severe lung irritation, coughing, pulmonary edema; excitement followed by depression. INGESTION causes nausea, vomiting, swelling of abdomen, headache, depression.
n-Hexane is a respiratory tract irritant andat high concentrations a narcotic. Its acutetoxicity is greater than that of n-pentane.Exposure to a concentration of 40,000 ppmfor an hour caused convulsions and death inmice. In humans a 10-minute exposure toabout 5000 ppm may produce hallucination,distorted vision, headache, dizziness, nausea,and irritation of eyes and throat. Chronicexposure to n-hexane may cause polyneuritis.
The metabolites of n-hexane injected inguinea pigs were reported as 2,5- hexanedioneand 5-hydroxy-2-hexanone, which arealso metabolites of methyl butyl ketone(DiVincenzo et al. 1976). Thus methyl butylketone and n- hexane should have similartoxicities. The neurotoxic metabolite, 2,5-hexanedione, however, is produced considerablyless in n-hexane. However, in the caseof hexane, the neurotoxic metabolite 2,5-hexanedione is produced to a much lesserextent. Continuous exposure to 250 ppmn-hexane produced neurotoxic effects in animals. Occupational exposure to 500 ppmmay cause polyneuropathy (ACGIH 1986).
Inhalation of n-hexane vapors have shownreproductive effects in rats and mice.
Behavior in Fire: Vapors may explode
Hexane is extremely flammable (NFPA rating = 3), and its vapor can travel a considerable distance to an ignition source and "flash back." Hexane vapor forms explosive mixtures with air at concentrations of 1.1 to 7.5 % (by volume). Hydrocarbons of significantly higher molecular weight have correspondingly higher vapor pressures and therefore present a reduced flammability hazard. Carbon dioxide or dry chemical extinguishers should be used for hexane fires.
Flammability and Explosibility
Hexane is extremely flammable (NFPA rating = 3), and its vapor can travel a
considerable distance to an ignition source and "flash back." Hexane vapor forms
explosive mixtures with air at concentrations of 1.1 to 7.5 % (by volume).
Hydrocarbons of significantly higher molecular weight have correspondingly higher vapor pressures and therefore present a reduced flammability hazard. Carbon dioxide or dry chemical extinguishers should be used for hexane fires.
Reactivity with Water: No reaction; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
n-Hexane is industrial chemical, emul sifier, in manufacture of plastics, resins; as a solvent, par ticularly in the extraction of edible fats and oils; as a laboratory reagent; and as the liquid in low temperature thermometers. Technical and commercial grades consist of 45 85% hexane, as well as cyclopentanes, isohexane, and 1% to 6% benzene.
Male rabbits exposed to 3000 ppm hexane (8 h/day, 6 days/week for 24 weeks) developed papillary proliferation of nonciliated bronchiolar cells. No tumors were found in mice painted with hexane and croton oil as cocarcinogen, presumably for the lifetime of each animal. Hexane is inactive as a tumorpromoting agent.
In diesel engine exhaust at a concentration of 1.2% of emitted hydrocarbons (quoted,
A constituent in gasoline. Harley et al. (2000) analyzed the headspace vapors of three grades of unleaded gasoline where ethanol was added to replace methyl tert-butyl ether. The gasoline vapor concentrations of hexane in the headspace were 4.31 wt % for regular grade, 3.74.8 wt % for midgrade, and 2.3 wt % for premium grade.
Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 1.82 and 268 mg/km, respectively (Schauer et al., 2002).
Biological. Hexane may biodegrade in two ways. The first is the formation of hexyl hydroperoxide,
which decomposes to 1-hexanol followed by oxidation to hexanoic acid. The other
pathway involves dehydrogenation to 1-hexene, which may react with water giving 1-hexanol
(Dugan, 1972). Microorganisms can oxidize alkanes under aerobic conditions (Singer and
Finnerty, 1984). The most common degradative pathway involves the oxidation of the terminal
methyl group forming 1-hexanol. The alcohol may undergo a series of dehydrogenation steps
forming a hexanal followed by oxidation to form hexanoic acid. The fatty acid may then be
metabolized by β-oxidation to form the mineralization products, carbon dioxide and water (Singer
and Finnerty, 1984).
Photolytic. An aqueous solution irradiated by UV light at 50 °C for 1 d resulted in a 50.51% yield of carbon dioxide (Knoevenagel and Himmelreich, 1976). Synthetic air containing gaseous nitrous acid and exposed to artificial sunlight (λ = 300–450 nm) photooxidized hexane into two isomers of hexyl nitrate and peroxyacetal nitrate (Cox et al., 1980).
Chemical/Physical. Complete combustion in air yields carbon dioxide and water vapor.
hexane should be used only in areas free of ignition sources, and quantities greater than 1 liter should be stored in tightly sealed metal containers in areas separate from oxidizers.
UN1208 Hexanes, Hazard Class: 3; Labels: 3-Flammable liquid.
Purify as for n-heptane. Modifications include the use of chlorosulfonic acid or 35% fuming H2SO4 instead of conc H2SO4 in washing the alkane, and final drying and distilling from sodium hydride. Unsaturated impurities can be removed by shaking the hexane with nitrating acid (58% H2SO4, 25% conc HNO3, 17% water, or 50% HNO3, 50% H2SO4), then washing the hydrocarbon layer with conc H2SO4, followed by H2O, drying, and distilling over sodium or n-butyl lithium. It can also be purified by distillation under nitrogen from sodium benzophenone ketyl solubilised with tetraglyme. Also purify it by passage through a silica gel column followed by distillation [Kajii et al. J Phys Chem 91 2791 1987]. It is a FLAMMABLE liquid and a possible nerve toxin. [Beilstein 1 IV 338.] Rapid purification: Distil, discarding the first forerun and stored over 4A molecular sieves.
May form explosive mixture with air. Contact with strong oxidizers may cause fire and explo sions. Contact with dinitrogen tetraoxide may explode @ 28℃.Attacks some plastics, rubber and coatings. May accumulate static electrical charges, and may cause ignition of its vapors.
Dissolve or mix the material with a combustible solvent and burn in a chemical incinera tor equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.
Hexane Preparation Products And Raw materials
- 2-Ethylhexyl bromide
- Ethyl 2-bromohexanoate
- BENZYL ISOCYANIDE
- Ethyl isocyanoacetate
- HEXYLMAGNESIUM BROMIDE
- Ethyl 2-bromoheptanoate
- 2-BROMOHEXANOYL BROMIDE
- METHYL ISOCYANOACETATE
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