1,5-Hexadiene is the organic compound with the formula (CH2)2(CH=CH2)2. It is a colorless, volatile liquid. It is used as a crosslinking agent and precursor to a variety of other compounds.

Synthesis

1,5-Hexadiene is produced commercially by the ethenolysis of 1,5-cyclooctadiene:

(CH2CH=CHCH2)2 + 2 CH2=CH2 → 2 (CH2)2CH=CH2

The catalyst is derived from Re2O7 on alumina.

A laboratory-scale preparation involves reductive coupling of allyl chloride using magnesium:

2 ClCH2CH=CH2 + Mg → (CH2CH=CH2)2 + MgCl2