Isolating Clove Oil from Cloves Using Steam Distillation
Abstract: In this experiment, clove oil is isolated from cloves by steam distillation, a technique often used to isolate liquid products from plants. The results of our extraction resulted in a percent yield of 5.8%.
Clove trees containing dried flower buds, also called cloves, are found are in India and the far east. Steam distillation of freshly ground cloves results in clove oil, a combination of several compounds. Eugenol accounts for the majority of the compound, roughly 85%-90%; while eugenol acetate comprises a smaller amount, roughly 9 to 10 percent. Clove oil is a part of a class of natural products called essential oils used as flavorings and perfumes and, in the past, were considered to be the “essence” of clove trees.
The principle of steam distillation is based on the fact that two immiscible liquids will boil a lower temperature together rather than individually. When two compounds are not miscible, co-distillation can performed instead. Dalton’s law relates the distillation of both compounds, stating that the total vapor pressure above the liquid is equal to the sum of the vapor pressures of each compound. This leads to a higher vapor pressure for the mixture which in turn, decreases the boiling point more than if it were a single component. Because each liquid vaporizes independently of one another in an ideal situation, respective mole fractions are not included in this equation. On the other hand, miscible mixtures are subject to simple and fractional distillations, while ideal mixtures follow Raoult’s law. This law dictates that the total vapor pressure of the system is equal to the addition of the products and the respective mole fractions of each compound.
Volatile compounds, which are unstable or have high boiling points, benefit from steam distillation because they can co-distill with water at relatively low temperatures. Decomposition that might occur at the...