iso-Butylene
Isobutylene (C4H8), also called butylene, is a hydrocarbon of significant industrial importance. It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. At standard room temperature and pressure it is a colorless, flammable gas. At extremely low temperatures it becomes a liquid.
Isobutylene is used as an intermediate in the production of a variety of products, including the high-octane fuel. It is also used in the preparation of organic compounds. Related compounds include isobutene, 2-methylpropene, and 1-dimethylethylene. Isobutylene is a gas at room temperature and becomes a liquid at extremely low temperatures.
Through hydroformylation, or oxo synthesis, the resulting aldehydes are easily converted into many secondary products.
Alkenes are polymerized by heating with catalysts to give high-octane gasolines, plastics, and synthetic rubber.
Classified as a hazardous material by the U. S. Department of Transportation, isobutylene is a highly flammable gas and presents a danger of explosion. It is usually stored as a compressed gas and, if released, may produce an oxygen-deficient atmosphere which presents an asphyxiation hazard.
Specifications
| Gas | iso-Butylene | Gas Density | |
|---|---|---|---|
| Chemical Symbol | (CH3)2CCH2 | Detection Principle | Pellistor, PID |
| PEL (ppm) | LEL (%) | ||
| IDHL (ppm) | UEL (%) | ||
| Industries | none | description | |
| applications |
Products
Industrial Applications
Fuel additives
In its pure form, isobutylene is used in organic synthesis and in the production of high octane aviation gasoline.
Isobutylene is reacted with methanol and ethanol to manufacture gasoline additives, methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), respectively. Alkylation with butane produces isooctane, another fuel additive.
Synthetic rubber
Polymerization of isobutylene produces butyl rubber (polyisobutylene), where it comprises 98% of the raw material used.
Alkenes serve as intermediates in the preparation of a variety of organic compounds. In the oxo process, alkenes react catalytically with carbon monoxide and hydrogen to give aldehydes.
Isobutylene is also used in the production of methacrolein, which is in the manufacture of polymers and synthetic resins.
Food Preservatives
Isobutylene in also used Friedel-Crafts alkylation of phenols to produce such antioxidants as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), two commonly used food preservatives.