Retention data are presented for the gas chromatographic separation of 1 -butene, frans-2-butene, cis-2butene, and 1,3-butcidiene, using several high boiling liquid substrates at 25°C. The most effective resolutions were obtained using aryl ethers modified by nitro or amine groups, aryl aldehydes and ethers, glycerol triacetate, and triethyl phosphate. The butenes produced by pyrolysis of butyl phosphates have been analyzed on a 1 3-foot column of o-nitrophenetole on Celite. The column characteristics are listed.