4pentene

4-Pentene is an organic compound with the chemical formula C5H10. It is an alkene, meaning it contains a carbon-carbon double bond. Specifically, the double bond is located between the fourth and fifth carbon atoms in the five-carbon chain. This places it as an isomer of pentene.

The structure of 4-pentene can be represented as CH2=CH-CH2-CH2-CH3. The IUPAC nomenclature indicates a five-carbon chain (pent-) with a double bond starting at the fourth position (4-). However, due to numbering conventions for alkenes, the double bond is typically assigned the lowest possible number. In this case, if the double bond were at the 4-5 position, it would be more logically numbered from the other end of the chain, making it 1-pentene. Therefore, "4-pentene" is not a standard IUPAC name and typically refers to compounds where the double bond is at the terminal position, which is 1-pentene. If a double bond is intended to be internal and not at the terminal position, other isomers like 2-pentene would be more appropriate names.

Because of the naming ambiguity, pure 4-pentene as a distinct, isolated compound with a double bond strictly between the 4th and 5th carbons of a linear chain is effectively the same as 1-pentene. 1-pentene is a colorless, flammable gas at room temperature and is used in the production of polyethylene and as a comonomer in the synthesis of other polymers. It is typically obtained from petroleum refining processes.