What´s Distillation?

Introduction

This experiment was done to isolate an organic substance, eugenol found in clove oil of cloves, which is immiscible with water through a new technique called steam distillation. Utilizing the high vapor pressure-low boiling point of water in steam distillation, eugenol with its low vapor pressure-high boiling point is extracted from cloves and checked for its purity content.

Theory

Distillation is the separation of two substances based on differences in boiling points, as in when a certain substances vapor pressure (from here on abbreviated as just VP) reaches and equals to the applied pressure (here, applied pressure is the atmospheric pressure). Steam distillation however specifically requires two immiscible liquids, one being water and the other an organic substance, eugenol in this experiment. In steam distillation, Dalton’s Law of Partial Pressures is applied. It states that P_Total=P_A^°+P_B^°, or in this case P_(Total VP)=P_water^°+P_eugenol^°. Here, since eugenol is an oil and cannot mix with water, both are two independent systems. This equation states that with the combined VPs of water and eugenol, a certain total VP will be achieved for the system; and once this total VP equals atmospheric pressure, the eugenol-water mixture will start to boil. When considering relative contributions to the total VP by water and eugenol, know that as the temperature of the system is increased the VP of water increases as does that of eugenol. But, since there is more water present, the water VP rises faster and builds higher than the eugenol VP. In other words, the rate at which water’s VP increases is going to be higher than the rate at which eugenol’s VP increases, thus contributing more to the total VP of the syst...

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... in extracting eugenol from cloves. Though this technique was effective in extracting pure eugenol, seen through the purity analysis made above and the fact that eugenol would have decomposed if made to boil on its own rather than through steam distillation, it was not however efficient. Efficiency was lacking when considering how much time was spent to simply do the extraction and only recover 8.607% of the theoretical mass of eugenol and how much money/supplies were used up in the extraction to only get that much eugenol. An alternative to help fix this efficiency problem could be to crush/grind the eugenol before steam distilling it so as to give more surface area to the amount present, thus lessening the supply cost and raising the quantity of end product; or a whole new technique can be explored, such as extraction of clove oil through solid-liquid extraction.