Isobutylene #115-11-7
CAS Number:115-11-7
Chemical Formula: C4H8
Synonyms:
2-Methylpropene-isobutylene
-METHYLPROPENE CYL. WITH 27 L (NET~14KG
HP-ISOBUTYLENE
Appearance: Colourless gas
MOQ (Minimum Order Quantity): 1 FCL (Full Container Load)
Isobutylene #115-11-7
Isobutylene is a colorless gas, m.p. -140.35 ℃, b.p. -6.8 ℃, n25D 1.381, relative density 0.673 (-49 ℃), 1.998 in gaseous state, can form explosive mixtures with the air, the explosion limit of 1.7% ~ 9.0% (v/v), soluble in organic solvents, easy to polymerize.
Colorless gas with a coal gas-like odor. The odor threshold concentration is 10 ppmv Nagata and Takeuchi (1990). This gas can be liquefied under pressure. The substance has low solubility in water, soluble in organic solvent, easy to polymerize. It is nonexplosive; however, it forms explosive mixtures with air. Containers holding isobutylene under pressure may explode if heated. The boiling point and freezing point of isobutylene are -6.9°C (19.6°F) and -141°C (-221°F), respectively. Isobutylene is extremely flammable. It is stable under recommended storage conditions and no decomposition may occur if stored and applied as directed.
Isobutylene is a colorless gas with a faint petroleum-like odor. For transportation it may be stenched. It is shipped as a liquefied gas under its own vapor pressure. Contact with the liquid can cause frostbite. It is easily ignited. Its vapors are heavier than air and a flame can flash back to the source of leak very easily. The leak can either be a liquid or vapor leak. It can asphyxiate by the displacement of air. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. It is used in the production of isooctane, a high octane aviation gasoline.
Application of Isobutylene
Isobutylene is an important petrochemical raw material. In the pesticide industry, it is mainly used for the preparation of the organophosphorus insecticide terbufos, the pyrethroid insecticide permethrin and the acaricide pyridaben. Industrially, high-concentration isobutylene is mainly used for the production of polyisobutylene and copolymerization with isoprene to produce butyl rubber. The alkylation reaction of isobutene and isobutane can produce high-octane alkylated gasoline, and methyl tert-butyl ether obtained by reacting with methanol is an excellent gasoline additive.
Isobutylene is used as a monomer for the production of various polymers such as butyl rubber, polybutene and polyisobutylene. The most important application of butyl rubber is the manufacture of tyres for cars and other vehicles. Other applications of butyl rubber, polybutene and poyisobutylene are lubricants (motor oils), adhesives, sealants and coatings. Another major use of isobutylene is the production of methyl-tert-butyl ether (MTBE) and ethy-tert-butyl ether (ETBE) which are gasoline blending components for cleaner burning fuels. Isobutylene is also used for the production of anti-oxidants, fragrances and gas odorization products.
| Isobutylene Chemical Properties |
| Melting point | −140 °C |
| Boiling point | −6.9 °C(lit.) |
| density | 0.5879 |
| vapor density | 2 (vs air) |
| vapor pressure | 3278 mm Hg ( 37.7 °C) |
| refractive index | 1.3811 |
| Fp | -80 °C |
| form | clear liquid |
| color | Colorless to Almost colorless |
| Odor Threshold | 10ppm |
| Water Solubility | 263mg/L(25 ºC) |
| FreezingPoint | -140.34℃ |
| Merck | 14,5141 |
| BRN | 773645 |
| Henry's Law Constant | 0.20, 0.26, 0.33, and 0.41 at 30, 40, 50, and 60 °C, respectively (Leung et al., 1987:Zhang et al., 2002) |
| Stability: | Stable. Highly flammable - readily forms an explosive mixture with air. Incompatible with strong oxidizing agents. |
| InChI | 1S/C4H8/c1-4(2)3/h1H2,2-3H3 |
| InChIKey | VQTUBCCKSQIDNK-UHFFFAOYSA-N |
| SMILES | CC(C)=C |
| LogP | 2.35 at 20℃ |
| CAS DataBase Reference | 115-11-7(CAS DataBase Reference) |
| EPA Substance Registry System | Isobutene (115-11-7) |
| Safety Information |
| Hazard Codes | F+ |
| Risk Statements | 12 |
| Safety Statements | 9-16-33 |
| RIDADR | UN 1055 |
| WGK Germany | - |
| RTECS | UD0890000 |
| F | 4.5-31 |
| Autoignition Temperature | 869 °F |
| TSCA | TSCA listed |
| DOT Classification | 2.1 (Flammable gas) |
| HazardClass | 2.1 |
| HS Code | 29012330 |
| Storage Class | 2A - Gases |
| Hazard Classifications | Flam. Gas 1 Press. Gas Liquefied gas |
| Hazardous Substances Data | 115-11-7(Hazardous Substances Data) |
| Toxicity | LC50 (inhalation) for mice 415 g/m3/2-h, rats 620 g/m3/4-h (quoted, RTECS, 1985). |
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