Dehydration of αγ-diphenylbutyl alcohol with potassium bisulphate yields 1,3-diphenyl-3-butene which can be oxidized to β-phenylpropiophenone. This 3-butene isomerizes on standing to a crystalline 1,3-diphenyl-1-butene which forms a dibromo-derivative and gives benzaldehyde and hydratropic aldehyde when ozonized. If αγ-diphenylbutyl alcohol is dehydrated with 20% sulphuric acid, it also yields 1, 3-diphenyl-3 butene, but this isomerizes to 1,3-diphenyl-2-butene from which acetophenone is obtained on oxidation.Staudinger's proof of the identity of the pyrolytic distyrene with 1,3-diphenyl-3-butene is not valid since αγ-diphenylpropane, present with the distyrene, produces β-phenylpropiophenone when oxidized.