Question

What alkene would you start with if you wanted to synthesize pentane?

Answer 1

You would use either pent-1-ene or pent-2-ene.

You want a 5-carbon pentane, so you start with a 5-carbon alkene.

The possibilities are pent-1-ene, CH₃CH₂CH₂CH=CH₂, and pent-2-ene. CH₃CH₂CH=CHCH₃.

You react either of these with hydrogen and a nickel catalyst.

The equations are

CH₃CH₂CH₂CH=CH₂ + H₂ → CH₃CH₂CH₂CH₂CH₃

and

CH₃CH₂CH=CHCH₃ + H₂ → CH₃CH₂CH₂CH₂CH₃