1,5-Pentanediol diacetate

Pentadiene has been prepared by the interaction of allyl bromide and vinyl bromide in the presence of magnesium and by the pyrolysis of 1,5-pentanediol diacetate or 4-penten-l-ol acetate. The present procedure is essentially that of Shoemaker and Boord with some modifications. ... 

Pentanediol diacetate,5 6b.p. 85-90°/0.9 mm., 1.4253, is obtained in 92-94% yield by adding a 10% excess of acetic anhydride to 1,5-pentanediol7 at 120-140°, refluxing the mixture for 2 hours, and distilling it at reduced pressure. The practical grade of 1,5-pen tanediol sold by the Eastman Kodak Company may be used. 

The residue from the first distillation is a mixture of acetic acid, 4-penten-l-ol acetate, and 1,5-pentanediol diacetate. Another 15-35 g. (6-15%) of 1,4-pentadiene can be obtained by passing the residue through the pyrolysis tube under the conditions described above. 

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