but2ene14dioate

But-2-ene-1,4-dioate, also known as maleate or fumarate depending on isomerism, is a dicarboxylic acid with the chemical formula C4H4O4. It is an unsaturated compound, meaning it contains a carbon-carbon double bond. The "but-2-ene" part of the name indicates a four-carbon chain with a double bond between the second and third carbon atoms. The "1,4-dioate" signifies two carboxylate groups (-COO-) located at positions one and four of this chain.

There are two geometric isomers of but-2-ene-1,4-dioate: cis-but-2-ene-1,4-dioate and trans-but-2-ene-1,4-dioate. The cis isomer is known as maleic acid, and the trans isomer is known as fumaric acid. These isomers have the same chemical formula and connectivity but differ in the spatial arrangement of atoms around the double bond. Maleic acid has both carboxylate groups on the same side of the double bond, while fumaric acid has them on opposite sides.

Maleic acid is a key intermediate in the industrial production of various chemicals, including polymers, agricultural chemicals, and pharmaceuticals. It is typically synthesized by the oxidation of benzene or n-butane. Fumaric acid, on the other hand, is an important metabolic intermediate found in the citric acid cycle and is used as a food additive for its acidic taste and preservative properties. It can be produced industrially through fermentation or chemical synthesis. The distinct physical and chemical properties of maleic and fumaric acids are a consequence of their differing stereochemistry.