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| 1,3-Butadiene | |
|---|---|
| General | |
| Systematic name | 1,3-Butadiene |
| Other names | Buta-1,3-diene Biethylene Erythrene Divinyl Vinylethylene |
| Molecular formula | C4H6 |
| SMILES | C=CC=C |
| Molar mass | 54.09 g/mol |
| Appearance | Colourless gas or refrigerated liquid |
| CAS number | * |
| Properties | |
| Density and phase | 0.64 g/cm3 at -6 °C, liquid |
| Solubility in water | 735 ppmw (25 °C) |
| Melting point | -108.9 °C (164.3 K) |
| Boiling point | -4.4 °C (268.8 K) |
| Viscosity | 0.25 cP at 0 °C |
| Dipole moment | ? D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Flammable, irritative |
| Flash point | -85 °C |
| R/S statement | R: S: |
| RTECS number | EI9275000 |
| Supplementary data page | |
| Structure & properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Related alkenes and dienes | 1,2-Butadiene Isoprene Chloroprene |
| Related compounds | Butane |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Chemical infobox | |
1,3-Butadiene is a simple conjugated diene. It is an important industrial chemical used as a monomer in the production of synthetic rubber. When the word butadiene is used, most of the time it refers to 1,3-butadiene.
The name butadiene can also refer to the isomer, 1,2-butadiene, which is a cumulated diene. However, this allene is difficult to prepare and has no industrial significance.
History
In 1863, a French chemist isolated a previously unknown hydrocarbon from the pyrolysis of amyl alcohol.Caventou, E. (1863), Annalen der Chemie und Pharmacie 127, 93. This hydrocarbon was identified as butadiene in 1886, after Henry Edward Armstrong isolated it from among the pyrolysis products of petroleum.Armstrong, H.E. Miller, A.K. (1886). "The decomposition and genesis of hydrocarbons at high temperatures. I. The products of the manufacture of gas from petroleum." Journal of the Chemical Society 49, 80. In 1910, the Russian chemist Sergei Lebedev polymerized butadiene, and obtained a material with rubber-like properties. This polymer was, however, too soft to replace natural rubber in many roles, especially automobile tires.
The butadiene industry originated in the years leading up to World War II. Many of the belligerent nations realized that in the event of war, they could be cut off from rubber plantations controlled by the British Empire, and sought to remove their dependence on natural rubber. In 1929, Eduard Tschunker and Walter Bock, working for IG Farben in Germany, made a copolymer of styrene and butadiene that could be used in automobile tires. Worldwide production quickly ensued, with butadiene being produced from grain alcohol in the Soviet Union and the United States and from coal-derived acetylene in Germany.
Production
In the United States, western Europe, and Japan, butadiene is produced as a byproduct of the steam cracking process used to produce ethylene and other olefins. When mixed with steam and briefly heated to very high temperatures (often over 900 °C), aliphatic hydrocarbons give up hydrogen to produce a complex mixture of unsaturated hydrocarbons, including butadiene. The quantity of butadiene produced depends on the hydrocarbons used as feed. Light feeds, such as ethane, give primarily ethylene when cracked, but heavier favor the formation of heavier olefins, butadiene, and aromatic hydrocarbons.
Butadiene is typically isolated from the other four-carbon hydrocarbons produced in steam cracking by extraction into a polar aprotic solvent such as acetonitrile or dimethylformamide, from which it is then stripped by distillation.Sun, H.P. Wristers, J.P. (1992). Butadiene. In J.I. Kroschwitz (Ed.), Encyclopedia of Chemical Technology, 4th ed., vol. 4, pp. 663–690. New York: John Wiley & Sons.
Butadiene can also be produced by the catalytic dehydrogenation of normal butane. The first such commercial plant, producing 65,000 tons per year of butadiene, began operations in 1957 in Houston, Texas.Beychok, M.R. and Brack, W.J., "First Postwar Butadiene Plant", Petroleum Refiner, June 1957.
From ethanol
In other parts of the world, including eastern Europe, China, and India, butadiene is also produced from ethanol. While not competitive with steam cracking for producing large volumes of butadiene, lower capital costs make production from ethanol a viable option for smaller-capacity plants. Two processes are in use.In the single-step process developed by Sergei Lebedev, ethanol is converted to butadiene, hydrogen, and water at 400–450 °C over any of a variety of metal oxide catalysts:Kirshenbaum, I. (1978). Butadiene. In M. Grayson (Ed.), Encyclopedia of Chemical Technology, 3rd ed., vol. 4, pp. 313–337. New York: John Wiley & Sons.
This process was the basis for the Soviet Union's synthetic rubber industry during and after World War II, and it remains in limited use in Russia and other parts of eastern Europe.
In the other, two-step process, developed by the Russian chemist Ivan Ostromislensky, ethanol is oxidized to acetaldehyde, which reacts with additional ethanol over a tantalum-promoted porous silica catalyst at 325–350 °C to yield butadiene:
This process was used in the United States to produce government rubber during World War II, and remains in use today in China and India.
Uses
Most butadiene is polymerized to produce synthetic rubber. While polybutadiene itself is a very soft, almost liquid material, polymers prepared from mixtures of butadiene with styrene or acrylonitrile, such as ABS, are both tough and elastic. Styrene-butadiene rubber is the material most commonly used for the production of automobile tires.
Smaller amounts of butadiene are used to make nylon via the intermediate adiponitrile, other synthetic rubber materials such as chloroprene, and the solvent sulfolane. Butadiene is used in the industrial production of cyclododecatriene via a trimerization reaction.
Safety
Contact with liquid butadiene can result in irritation of the skin, eyes, and mucous membranes. Since it often stored as a refrigerated liquid, frostbite is another possible consequence of exposure. When inhaled, butadiene is a mild depressant and can result in drowsiness, although very high concentrations are necessary to produce unconsciousness or death.
In some animals, long-term exposure to butadiene can result in cancer of the liver or kidneys. Butadiene is a potent carcinogen in mice, but only a weak carcinogen in rats. Studies of workers in chemical plants using butadiene have shown no conclusive increase in cancer risk for whatever amount of butadiene these workers may have been exposed to, so butadiene remains classified as only a potential human carcinogen.
External links
References
Butadien | Butadieno | Butadieen | ブタジエン | Butadien | Бутадиен | 丁二烯
"1,3-Butadiene"