1,3-Butadiene

1,3-Butadiene is a simple 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 allene is difficult to prepare and has no industrial significance.

History

In 1863, a French chemist isolated a previously unknown hydrocarbon from the 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 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 aromatic hydrocarbons.

Butadiene is typically isolated from the other four-carbon distillation.^[3]

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.^[4]

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:^[5]

2 H₂

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 silica catalyst at 325–350 °C to yield butadiene:^[5]

CH₃CHO → CH₂=CH-CH=CH₂ + 2 H₂O

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 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 cyclododecatriene via a trimerization reaction.

Safety

At acute high exposure, damage to the central nervous system will start to occur. Symptoms such as distorted blurred vision, vertigo, general tiredness, decreased blood pressure, headache, nausea, decreased pulse rate, and fainting may be witnessed. As the exposure to butadiene occurs at a higher level and for a longer duration, the effects witnessed will become more serious. The actual link between chronic effects of butadiene has been argued over the years, though human epidemiological studies have been performed over the years showing increased risks in serious adverse health effects.

Several studies show butadiene exposure increases risk in cardiovascular diseases and cancer. Animal data suggests the carcinogenic effects of butadiene may have a higher sensitivity to females over men when exposed to the chemical. While this data reveals important implications to the risks of human exposure to butadiene, more data is necessary to draw more conclusive risk assessments. There is also a lack of human data on the effects butadiene has on reproductive and developmental effects shown to occur in mice, but animal studies have shown breathing butadiene during pregnancy can increase the number of birth defects.

See also

• Cyclobutadiene
• Polybutadiene
• Hydroxyl-terminated polybutadiene

References

1. ^ Caventou, E. (1863), Annalen der Chemie und Pharmacie 127, 93.
2. ^ 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.
3. ^ 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.
4. ^ Beychok, M.R. and Brack, W.J., "First Postwar Butadiene Plant", Petroleum Refiner, June 1957.
5. ^ ^{a b} Kirshenbaum, I. (1978). Butadiene. In M. Grayson (Ed.), Encyclopedia of Chemical Technology, 3rd ed., vol. 4, pp. 313–337. New York: John Wiley & Sons.