D-limonene from oranges

Limonene, aka 4-isopropenyl-1-methylcyclohexene or dipentene, is a colourless or slightly yellow liquid. Naturally it occurs in many citrus fruits. It's the chemical that gives citrus rinds their wonderful smell.

I had a go at extracting it from orange peel via steam distillation. I started with five oranges and grated all the rinds of them. Next I placed the rinds into a round bottom flask with 150ml water and set up for simple distillation. I kept the distillation going until around 10ml of liquid was left in the round bottom. Once the distillation was complete I transferred the distillate to a graduated cylinder and noticed an oily top layer, which smelled strongly of citrus. Limonene is a nonpolar hydrocarbon so it doesn't mix with water.

I used a pipette to extract the top limonene layer. This was my final product: