Methylcyclohexane Chemical Properties
- Melting point:
- -126.3 °C
- Boiling point:
- 101 °C(lit.)
- 0.77 g/mL at 25 °C(lit.)
- vapor density
- 3.4 (vs air)
- vapor pressure
- 37 mm Hg ( 20 °C)
- refractive index
- Flash point:
- 25 °F
- storage temp.
- Flammables area
- explosive limit
- Odor Threshold
- Water Solubility
- 0.1 g/L (20 ºC)
- λ: 207 nm Amax: 1.00
λ: 221 nm Amax: 0.40
λ: 232 nm Amax: 0.15
λ: 260 nm Amax: 0.05
λ: 300-400 nm Amax: 0.01
- Henry's Law Constant
- 0.0678 at 25.0 °C (Ramachandran et al., 1996)
- Exposure limits
- NIOSH REL: TWA 400 ppm (1,600 mg/m3), IDLH 1,200 ppm; OSHA PEL: TWA 500 ppm (2,000 mg/m3); ACGIH TLV: TWA 400 ppm (adopted).
- Stable. Very flammable. Incompatible with strong oxidizing agents.
- CAS DataBase Reference
- 108-87-2(CAS DataBase Reference)
- NIST Chemistry Reference
- Cyclohexane, methyl-(108-87-2)
- EPA Substance Registry System
- Methylcyclohexane (108-87-2)
- Hazard Codes
- Risk Statements
- Safety Statements
- UN 2296 3/PG 2
- WGK Germany
- Autoignition Temperature
- 545 °F
- HS Code
- 2902 19 00
- Hazardous Substances Data
- 108-87-2(Hazardous Substances Data)
- Acute oral LD50 for mice 2,250 mg/kg (quoted, RTECS, 1985).
Methylcyclohexane Usage And Synthesis
Methylcyclohexane, an alkene, is a colorless liquid with a faint benzene-like odor. The odor threshold is 630 ppm (this is above the OEL).
Clear colorless, very flammable liquid with a faint odor similar to benzene or cyclohexane. An odor threshold concentration of 150 ppbv was reported by Nagata and Takeuchi (1990).
Solvent; starting material in the synthesis of toluene.
Methylcyclohexane is separated by distillation from crude petroleum oils, and also produced by hydrogenation of toluene, reaction of benzene with methane, or acidic hydrocracking of polycyclic aromatics.
A clear colorless liquid with a petroleum-like odor. Flash point 25°F. Less dense than water and insoluble in water. Vapors heavier than air.
Air & Water Reactions
Highly flammable. Insoluble in water.
Saturated aliphatic hydrocarbons, such as Methylcyclohexane, may be incompatible with strong oxidizing agents like nitric acid. Charring of the hydrocarbon may occur followed by ignition of unreacted hydrocarbon and other nearby combustibles. In other settings, aliphatic saturated hydrocarbons are mostly unreactive. They are not affected by aqueous solutions of acids, alkalis, most oxidizing agents, and most reducing agents.
Flammable, dangerous fire risk. Lowerexplosive limit 1.2% in air. Upper respiratory tractirritant, central nervous system impairment, liverand kidney damage.
Harmful if inhaled or swallowed. Vapor or mist is irritating to the eyes, mucous membrane and upper respiratory tract and skin. Narcotic effects and dermititis.
Special Hazards of Combustion Products: Vapor may travel considerable distance to a source of ignition and flashback containing explosion may occur during fire conditions. Forms explosive mixtures in air.
Moderately toxic by ingestion. Mildly toxic by inhalation and skin contact. This material does not cause irritation to the eyes and nose, and, even at the level of 500 ppm, exhbits only a very faint odor. Therefore, it cannot be said to have any warning properties. It is believed to be about three times as toxic as hexane, and has caused death by tetanic spasm in animals. In sublethal concentrations, it causes narcosis and anesthesia. Dangerous fire hazard and moderate explosion hazard when exposed to heat, flame, or oxidzers. To fight fire, use foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and fumes.
Methylcyclohexane is used as a solvent for cellulose derivatives particularly with other solvents; and as an organic intermediate in organic synthesis. A component of jet fuel.
Schauer et al. (1999) reported methylcyclohexane in a diesel-powered medium-duty truck
exhaust at an emission rate of 620 μg/km.
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 methylcyclohexane was 8.6 mg/kg of pine burned. Emission rates of methylcyclohexane were not measured during the combustion of oak and eucalyptus.
California Phase II reformulated gasoline contained methylcyclohexane at a concentration of 7.87 mg/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 1.86 and 274 mg/km, respectively (Schauer et al., 2002).
Biological. May be oxidized by microbes to 4-methylcyclohexanol, which may oxidize to give
4-methylcycloheptanone (Dugan, 1972).
Photolytic. Based on a photooxidation rate constant 1.04 x 10-11 cm3/molecule?sec for the reaction of cyclohexane and OH radicals in the atmosphere at 298 K, the estimated lifetime of methylcyclohexane is 13 h (Altshuller, 1991).
Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. Methycyclohexane will not hydrolyze in water because it does not contain a hydrolyzable functional group.
Complete combustion in air yields carbon dioxide and water. Incomplete combustion also yields carbon monoxide.
UN2296 Methylcyclohexane, Hazard Class: 3; Labels: 3-Flammable liquid.
Passage through a column of activated silica gel gives material transparent down to 220nm. It can also be purified by passage through a column of activated basic alumina, or by azeotropic distillation with MeOH, followed by washing out the MeOH with H2O, drying and distilling. Methylcyclohexane can be dried with CaSO4, CaH2 or sodium. It has also been purified by shaking with a mixture of conc H2SO4 and HNO3 in the cold, washing with H2O, drying with CaSO4 and fractionally distilling it from potassium. Percolation through a Celite column impregnated with 2,4-dinitrophenylhydrazine (DNPH), phosphoric acid and H2O (prepared by grinding 0.5g DNPH with 6mL 85% H3PO4, then mixing with 4mL of distilled H2O and 10g of Celite) removes carbonyl-containing impurities. [Cowan et al. J Chem Soc 1865 1939, Beilstein 5 III 65, 5 IV 94.]
Vapor 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, rubber 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.
Methylcyclohexane Preparation Products And Raw materials
- Methyl cyclohexanecarboxylate
- METHYL O-METHYLPODOCARPATE
- Cyclohexanecarboxylic acid chloride
- Cyclohexene oxide
- Cyclohexylmethyl bromide
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