Pentane Chemical Properties
- Melting point:
- -130 °C
- Boiling point:
- 36 °C
- 0.626 g/mL at 25 °C(lit.)
- vapor density
- 2.48 (vs air)
- vapor pressure
- 26.98 psi ( 55 °C)
- refractive index
- Flash point:
- −57 °F
- storage temp.
- ethanol: soluble(lit.)
- >14 (Schwarzenbach et al., 1993)
- Like a gasoline.
- Relative polarity
- explosive limit
- Water Solubility
- λ: 200 nm Amax: ≤0.70
λ: 210 nm Amax: ≤0.20
λ: 220 nm Amax: ≤0.07
λ: 230 nm Amax: ≤0.02
λ: 250 nm Amax: ≤0.004
- Henry's Law Constant
- 1.20 at 25 °C (J?nsson et al., 1982)
- Exposure limits
- TLV-TWA 600 ppm (～1800 mg/m3) (ACGIH), 1000 ppm (～3000 mg/m3) (OSHA), 500 ppm (～1500 mg/m3) (MSHA); STEL 750 ppm (～2250 mg/m3) (ACGIH).
- CAS DataBase Reference
- 109-66-0(CAS DataBase Reference)
- NIST Chemistry Reference
- EPA Substance Registry System
- Pentane (109-66-0)
- Hazard Codes
- Risk Statements
- Safety Statements
- UN 1265 3/PG 2
- WGK Germany
- Autoignition Temperature
- 500 °F
- HS Code
- Hazardous Substances Data
- 109-66-0(Hazardous Substances Data)
- LC (in air) in mice: 377 mg/l (Fühner)
Pentane Usage And Synthesis
n-Pentane is a flammable liquid. It has applications in industry as an aerosol propellant and as an important component of engine fuel. N-propane is a CNS depressant. Studies with dogs have indicated that it induces cardiac sensitization. In high concentrations it causes incoordination and inhibition of the righting refl exes.
Pentane is a colorless liquid. Gas above 36C. Gasoline-like odor.
Clear, colorless, volatile liquid with an odor resembling gasoline. An odor threshold concentration of 1.4 ppmv was reported by Nagata and Takeuchi (1990).
n-Pentane occurs in volatile petroleum fractions(gasoline) and as a constituent ofpetroleum ether. It is used as a solvent, in themanufacture of low-temperature thermometers,and as a blowing agent for plastics.
Pentane is produced by fractional distillation of natural gas liquids and crude oil. It is also produced by the catalytic crackdown of naphtha.
A straightchain alkane obtained by distillation of crude oil.
pentane: A straight-chain alkanehydrocarbon, C5H12; r.d. 0.63; m.p.–129.7°C; b.p. 36.1°C. It is obtainedby distillation of petroleum.
A clear colorless liquid with a petroleum-like odor. Flash point 57°F. Boiling point 97°F. Less dense than water and insoluble in water. Hence floats on water. Vapors are heavier than air.
Air & Water Reactions
Highly flammable. Insoluble in water.
Pentane is incompatible with strong oxidizers. Pentane is also incompatible with strong acids, alkalis, and oxygen. Mixtures with chlorine gas have produced explosions. Pentane will attack some forms of plastics, rubber, and coatings. .
Low toxicity. Very high vapor concentrations produce narcosis. Aspiration into lungs can produce chemical pneumonitis and/or pulmonary edema.
n-Pentane did not exhibit any marked toxicityin animals. However, inhalation ofits vapors at high concentrations can causenarcosis and irritation of the respiratorypassages. Such effects may be observedwithin the range 5–10% concentration inair. In humans, inhalation of 5000 ppm for10 minutes did not cause respiratory tractirritation or other symptoms (Patty and Yant1929).
There is no report in the literature indicatingany adverse effects from pentaneother than narcosis and irritation. An intravenousLD50 value in mouse is recorded as446 mg/kg (NIOSH 1986).
Behavior in Fire: Containers may explode
Reactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Moderately toxic by inhalation and intravenous routes. Narcotic in high concentration. The liquid can cause blisters on contact. Flammable liquid. Highly dangerous fire hazard when exposed to heat, flame, or oxidizers. Severe explosion hazard when exposed to heat or flame. Shock can shatter metal containers and release contents. To fight fire, use foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes
Pentane is used in manufacture of ice, low-temperature thermometers; in solvent extraction processes; as a blowing agent in plastics; as a fuel; as a chemical intermediate (for amylchlorides, e.g.).
Schauer et al. (1999) reported pentane in a diesel-powered medium-duty truck exhaust at
an emission rate of 1,860 μg/km.
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 pentane in the headspace were 14.2 wt % for regular grade, 12.6 wt % for midgrade, and 9.3 wt % for premium grade.
California Phase II reformulated gasoline contained pentane at a concentration of 27.6 g/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 4.29 and 536 mg/km, respectively (Schauer et al., 2002).
Schauer et al. (2001) measured organic compound emission rates for volatile organic compounds, gas-phase semi-volatile organic compounds, and particle-phase organic compounds from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission rate of pentane was 4.7 mg/kg of pine burned. Emission rates of pentane were not measured during the combustion of oak and eucalyptus.
Biological. n-Pentane may biodegrade in two ways. The first is the formation of pentyl
hydroperoxide, which decomposes to 1-pentanol followed by oxidation to pentanoic acid. The
other pathway involves dehydrogenation to 1-pentene, which may react with water giving 1-
pentanol (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-pentanol. The alcohol may undergo a series of dehydrogenation
steps forming an aldehyde (valeraldehyde) then a fatty acid (valeric acid). The fatty acid may then
be metabolized by β-oxidation to form the mineralization products, carbon dioxide and water
(Singer and Finnerty, 1984). Mycobacterium smegnatis was capable of degrading pentane to 2-
pentanone (Riser-Roberts, 1992).
Photolytic. When synthetic air containing gaseous nitrous acid and pentane was exposed to artificial sunlight (λ = 300–450 nm) methyl nitrate, pentyl nitrate, peroxyacetal nitrate, and peroxypropionyl nitrate formed as products (Cox et al., 1980).
Chemical/Physical. Complete combustion in air yields carbon dioxide and water. Pentane will not hydrolyze because it does not contain a hydrolyzable functional group.
UN1265 Pentanes Hazard Class: 3; Labels: 3-Flammable liquid.
Stir the pentane with successive portions of conc H2SO4 until there is no further coloration during 12hours, then with 0.5N KMnO4 in 3M H2SO4 for 12hours, wash with water and aqueous NaHCO3. Dry it with MgSO4 or Na2SO4, then P2O5 and fractionally distil it through a column packed with glass helices. It is also purified by passage through a column of silica gel, followed by distillation and storage with sodium hydride. An alternative purification is by azeotropic distillation with MeOH, which is subsequently washed out from the distillate (using water), followed by drying and re-distilling. For removal of carbonyl-containing impurities, see n-heptane. Also purify it by fractional freezing (ca 40%) on a copper coil through which cold air is passed, then wash with conc H2SO4 and fractionally distil it. [Beilstein 1 IV 303.]
Vapors may form explosive mixture with air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Attacks some plastics, rubbers, and coatings.
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.
Pentane Preparation Products And Raw materials
- Ethyl 2-bromovalerate
- 2-BROMOHEXANOYL BROMIDE
- 2-Ethylhexyl bromide
- Ethyl 2-bromoheptanoate
- Cyclopentyl chloride
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