A ternary V-Ti-P mixed oxide is shown to catalytically dehydrate 2- methyl-tetrahydrofuran in high conversion to give piperylene, in good yield. Volatile products collected from this reaction contain piperylene in concentrations as high as 80 percent by weight. Dehydration of glycerol to acrolein in high conversion and moderate selectivity is also demonstrated. The catalyst is also shown to dehydrate other alcohols and ether substrates. The catalyst is resistant to deactivation and maintains activity between runs.