Butadiene

Ball-and-stick model of trans-1,3-butadiene, the most important type of butadiene. Black balls are carbon atoms and white balls are hydrogen atoms.

Butadiene is a chemical compound made of carbon and hydrogen (a hydrocarbon). It has the chemical formula C₄H₆. Because it has two double bonds between carbon atoms, it is called a diene.

Butadiene is used to make rubber and other polymers.

Structure

Butadiene has two structural isomers. 1,2-butadiene has the two double bonds next to each other, and 1,3-butadiene has them on opposite ends of the molecule. Only a small fraction of butadiene is 1,2-butadiene, and it is not important in the chemical industry.

1,3-butadiene has two rotational isomers, depending on whether the double bonds are on the same side (the cis configuration) or opposite sides (the trans configuration) of the bond separating them. The trans configuration is more stable, but it can rotate to become the cis configuration for some reactions (such as Diels-Alder reactions).