2-Methylbutane CAS 78-78-4
Introduction：Basic information about 2-Methylbutane CAS 78-78-4, including its chemical name, molecular formula, synonyms, physicochemical properties, and safety information, etc.
2-Methylbutane Basic information
| Product Name: | 2-Methylbutane |
| Synonyms: | iso-C5H12;Isopentan;iso-Pentan;methylbutane;2-METHYLBUTANE, 99.5+%, HPLC GRADE;2-METHYLBUTANE, 99+%, SPECTROPHOTOMETRIC GRADE;2-METHYLBUTANE, REAGENTPLUS, >=99%;2-METHYLBUTANE, ANHYDROUS, 99+% |
| CAS: | 78-78-4 |
| MF: | C5H12 |
| MW: | 72.15 |
| EINECS: | 201-142-8 |
| Product Categories: | ACS and Reagent Grade Solvents;ReagentPlus Solvent Grade Products;Solvent Bottles;Solvent by Application;Solvent Packaging Options;Solvents;Sure/Seal Bottles;Anhydrous Solvents;SAJ First Grade (Japan only);Solvents by Special Grades (Japan Customers Only);refrigerants;Organics;Industrial/Fine Chemicals;Pyrazoles;Amber Glass Bottles;NMR;Spectrophotometric Grade;Spectrophotometric Solvents;Spectroscopy Solvents (IR;UV/Vis);Analytical Reagents;Analytical/Chromatography;CHROMASOLV for HPLC;Chromatography Reagents &HPLC &HPLC Grade Solvents (CHROMASOLV);HPLC/UHPLC Solvents (CHROMASOLV);UHPLC Solvents (CHROMASOLV) |
| Mol File: | 78-78-4.mol |
2-Methylbutane Chemical Properties
| Melting point | -160 °C |
| Boiling point | 30 °C(lit.) |
| density | 0.62 g/mL at 25 °C(lit.) |
| vapor density | 2.6 (vs air) |
| vapor pressure | 11.17 psi ( 20 °C) |
| refractive index | n |
| Fp | −51 °C |
| storage temp. | 2-8°C |
| solubility | 0.048g/l |
| form | Liquid |
| pka | >14 (Schwarzenbach et al., 1993) |
| color | Clear colorless |
| Odor | gasoline-like odor |
| Odor Threshold | 1.3ppm |
| explosive limit | 1.3-7.6%(V) |
| Water Solubility | Miscible with water, hydrocarbons, oils, alcohol and ether. |
| λmax | λ: 192 nm Amax: 1.00 λ: 210 nm Amax: 0.30 λ: 220 nm Amax: 0.07 λ: 240-400 nm Amax: 0.01 |
| BRN | 1730723 |
| Henry's Law Constant | (atm?m3/mol):1.24 at 25 °C (approximate - calculated from water solubility and vapor pressure) |
| Exposure limits | ACGIH TLV: TWA 600 ppm (adopted). |
| Dielectric constant | 1.8（20℃） |
| Stability: | Stable. Extremely flammable. Incompatible with strong oxidizing agents. Vapour-air mixtures explosive in certain proportions. Incompatible with rubber, various plastics. The vapour, being heavier than air, may roll over surfaces and collect in low points. Note low flash point. |
| Cosmetics Ingredients Functions | PROPELLANT SOLVENT VISCOSITY CONTROLLING |
| Cosmetic Ingredient Review (CIR) | 2-Methylbutane (78-78-4) |
| InChI | 1S/C5H12/c1-4-5(2)3/h5H,4H2,1-3H3 |
| InChIKey | QWTDNUCVQCZILF-UHFFFAOYSA-N |
| SMILES | CCC(C)C |
| LogP | 3.4 at 20℃ |
| CAS DataBase Reference | 78-78-4(CAS DataBase Reference) |
| NIST Chemistry Reference | Butane, 2-methyl-(78-78-4) |
| EPA Substance Registry System | 2-Methylbutane (78-78-4) |
Safety Information
| Hazard Codes | F+,Xn,N |
| Risk Statements | 12-51/53-65-66-67 |
| Safety Statements | 9-16-29-33-61-62 |
| RIDADR | UN 1265 3/PG 1 |
| OEB | A |
| OEL | TWA: 120.0 ppm; 350.0 mg/m3, STEL: 610.0 ppm; 1800.0 mg/m3 |
| WGK Germany | 2 |
| RTECS | EK4430000 |
| Autoignition Temperature | 788 °F |
| TSCA | TSCA listed |
| HazardClass | 3 |
| PackingGroup | I |
| HS Code | 29011000 |
| Storage Class | 3 - Flammable liquids |
| Hazard Classifications | Aquatic Chronic 2 Asp. Tox. 1 Flam. Liq. 1 STOT SE 3 |
| Hazardous Substances Data | 78-78-4(Hazardous Substances Data) |
| Chemical Properties | 2-Methylbutane (isopentane), C5H12, is a flammable liquid and exhibits physical properties very similar to those of pentane. It has been detected in urban air. 2-Methylbutane is an alkane that is butane substituted by a methyl group at position 2. It has a higher BP than butane because, although similarly branched, it has a higher MW. A useful analogy for comparing molecules with the same size of longest chain is that of cylindrical-shaped molecules. It has a role as a refrigerant. Biological samples flash frozen for example with a combination of liquid nitrogen and methylbutane can then be used for storage, cryosection, etc. |
| Physical properties | Clear, colorless, watery, very flammable liquid with a pleasant odor. Evaporates quickly whenspilled. An odor threshold concentration of 1.3 ppmv was reported by Nagata and Takeuchi(1990). |
| Uses | Isopentane is an organic, branched-chain alkane with five carbon atoms. 2-Methylbutane undergoes catalytic dehydrogenation in the presence of chromia-alumina catalyst to form isoamylenes, which can undergo further dehydrogenation to form isoprene. It may also be used as a solvent in the preparation of trans-Bis(triethylphosphine) (hydroxy carbonyl) (phenyl) platinum(II), a metallacarboxylic acid. |
| Uses | 2-Methylbutane is used as a chemical intermediate. It acts as a blowing agent for polystyrene and gasoline additive. It is used as a solvent of polyethylene and involved in the preparation of polystyrene foam and polyurethane foam. Further, it is used in a closed loop in geothermal power production to operate turbines. In addition to this, it is used to freeze biological samples like tissues in place of dry ice for cryosectioning in histology. |
| Preparation | 2-Methylbutane was synthesized by liquid-phase catalytic isomerization at 95°C using pentane as raw material. |
| Production Methods | Isopentane is produced by fractional distillation of naturalgas liquids and crude oil. |
| Definition | ChEBI: 2-methylbutane is an alkane that is butane substituted by a methyl group at position 2. It has a role as a refrigerant. |
| General Description | Watery colorless liquid with a gasoline-like odor. Floats on water. Flammable, irritating vapor is produced. Boiling point is 82°F. |
| Air & Water Reactions | Highly flammable. Insoluble in water. |
| Reactivity Profile | 2-Methylbutane is a fire and explosion hazard when in contact with oxidizing agents. . |
| Health Hazard | Inhalation causes irritation of respiratory tract, cough, mild depression, irregular heartbeat. Aspiration causes severe lung irritation, coughing, pulmonary edema; excitement followed by depression. Ingestion causes nausea, vomiting, swelling of abdomen, headache, depression. |
| Fire Hazard | Behavior in Fire: Highly volatile liquid. Vapors may explode when mixed with air. |
| Flammability and Explosibility | Extremely flammable |
| Safety Profile | Mddly toxic and narcotic by inhalation. See also PENTANE. Flammable liquid. A very dangerous fire and explosion hazard when exposed to heat, flame, or oxidzers. Keep away from sparks, heat, or open flame; can react with oxidizing materials. To fight fire, use foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. |
| Source | A constituent in gasoline. Harley et al. (2000) analyzed the headspace vapors of threegrades of unleaded gasoline where ethanol was added to replace methyl tert-butyl ether. Thegasoline vapor concentrations of 2-methylbutane in the headspace were 24.1 wt % for regulargrade, 24.8 wt % for mid-grade, and 26.0 wt % for premium grade. Schauer et al. (2001) measured organic compound emission rates for volatile organiccompounds, gas-phase semi-volatile organic compounds, and particle-phase organic compoundsfrom the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emissionrate of 2-methylbutane was 5.6 mg/kg of pine burned. Emission rates of 2-methylbutane were notmeasured during the combustion of oak and eucalyptus. California Phase II reformulated gasoline contained 2-methylbutane at a concentration of 79.2g/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and withoutcatalytic converters were 3.69 and 148 μg/km, respectively (Schauer et al., 2002). |
| Environmental fate | Photolytic. When synthetic air containing gaseous nitrous acid and 2-methylbutane was exposedto artificial sunlight (λ = 300–450 nm), acetone, acetaldehyde, methyl nitrate, peroxy-acetalnitrate, propyl nitrate, and pentyl nitrate were formed (Cox et al., 1980). Based upon a photooxidation rate constant of 3.90 x 10-12 cm3/molecule?sec with OH radicals insummer daylight, the atmospheric lifetime is 36 h (Altshuller, 1991). At atmospheric pressure and300 K, Darnall et al. (1978) reported a rate constant of 3.78 x 10-12 cm3/molecule?sec for the samereaction. Cox et al. (1980) reported a rate constant of 5.0 x 10-11 cm3/molecule?sec for the reaction ofgaseous 2-methylbutane with OH radicals based on a value of 8 x 10-12 cm3/molecule?sec for thereaction of ethylene with OH radicals. Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. 2-Methylbutane will not hydrolyze because it does not contain a hydrolyzable functional group. |
| Purification Methods | Stir isopentane for several hours in the cold with conc H2SO4 (to remove olefinic impurities), then wash it with H2O, aqueous Na2CO3 and H2O again. Dry it with MgSO4 and fractionally distil it using a Todd column packed with glass helices. Material transparent down to 180nm is obtained by distilling from sodium wire, and passing through a column of silica gel which had previously been dried in place at 350o for 12hours before use. [Potts J Phys Chem 20 809 1952, Beilstein 1 IV 320.] |
| Toxics Screening Level | The initial threshold screening level (ITSL) for isopentane (also called 2-methylbutane) is 17,700 μg/m3 (8-hr averaging time). |
2-Methylbutane Preparation Products And Raw materials
| Raw materials | Sodium-->Silica gel-->Pentane-->Naphthalene-->Dehydrolyzing agent-->2,2-Dimethylbutane-->3,3-DIMETHYLHEPTANE-->2,3-DIMETHYLHEPTANE-->TETRA-N-BUTYLSILANE |
| Preparation Products | Isoprene-->Amobarbital-->Cyclopentane-->3,3-Dimethylpentane-->1-CHLORO-2-METHYLBUTANE-->N,N,N',N'-TETRAMETHYL-1,6-HEXANEDIAMINE-->3,3-Dimethyloctane-->2,3,4-TRIMETHYLPENTANE-->1-CHLORO-3-METHYLBUTANE-->2,3-Dimethylpentane |
