Efficient Dehydration of C-α,ω-Alkanediols to Alkadienes as Catalyzed by Aliphatic Acids.

The aliphatic-acid-mediated dehydration of C-α,ω-alkanediols to alkadienes proceeds in a stepwise manner: C-α,ω-alkanediols react with aliphatic acids first to generate diesters; subsequent pyrolysis of the latter produces alkadienes. The highest yields of 1,5-hexadiene, 1,7-octadiene, and 1,9-decadiene were up to 70.3, 74.8, and 90.3%, respectively. It turned out that pyrolysis favors the diester with a longer carbon chain more, while acetic acid outperformed the other aliphatic acids in the pyrolysis step that a relatively lower temperature was enough for a high yield of alkadienes.