Limonene is commonly found in citrus fruits, and it has a very strong orange-lemon scent. It is commonly used in the flavoring and the perfume industry, but is also used as a solvent. In most citrus fruits, the highest concentration of limonene is found in the peel, so that is where we’re going to extract it from. Limonene is prone to degradation, but using steam distillation, we can separate it without it breaking down. The hard orange portion of the peel of two oranges was shaved off using a cheese grater. Afterwards, the orange should look like this, where the dark orange portion of the peel has been removed. The orange peels can then be transferred to a round-bottom flask. To this was added 100 mL of water. The water also helped to rinse off orange peel that remained stuck to the funnel. Then, a simple distillation is carried out. In this process the water and the limonene will co-distill. Once distillation has started, the distillate will start coming over and we should, in theory, see two layers forming. A total of 50 mL of distillate was collected and, at the top, you can clearly see another layer. This upper layer was removed using a needle and a syringe. Using this method, you need to be very careful not to collect any of the water layer and it’s honestly probably better just to use a separatory funnel. The final limonene product was then transferred to a dram vial. The yield that you can expect is about 1% of the total mass of peel that was used.