Partition Coefficient Lab Report

The partition coefficient provides an approximate relationship of the solubility of benzoic acid in the organic layer versus the aqueous layer. The partition coefficient is extremely useful in the health sciences due to the crucial information it gives for establishing proper drug delivery. Having precise drug delivery is vital for making sure pharmaceutical compounds are distributed in the body as safely and effectively as possible. In this experiment, a liquid-liquid extraction was performed in order to purify benzoic acid. In part A of this experiment, benzoic acid is dissolved in methylene chloride and water is then added to this mixture. Two layers form in the culture tube because water and methylene chloride are immiscible. The organic

Once the organic layer has been completely isolated, it is placed in a sand bath to boil off the methylene chloride. Part B of the experiment shares a very similar process to part A, except rather than using deionized water, sodium bicarbonate is used. This switch in aqueous layers changes the results significantly. When deionized water is used for the liquid-liquid extraction, the reverse reaction is strongly favored due to water producing benzoate and hydronium. Contrastingly, the forward reaction in part B of this experiment is strongly favored due to sodium bicarbonate producing sodium benzoate and carbonic acid. More benzoic acid is recovered in part A because the forward reaction is favored, highlighting how hydronium is unstable and prefers to be in its water form, thus breaking down benzoate back into benzoic acid. Contrastingly, in part B the reverse reaction is favored because carbonic acid is more stable than sodium bicarbonate therefore benzoic acid gets broken down to sodium benzoate more and thus that's why there is a lower amount of benzoic acid recovered in part B compared to part A. This

Reaction vials are more accurate because the organic layer is more easily identified due to the pointed tip of the vial. The pointed tip also makes it easier to collect all of the organic layer in one go when using the Pasteur pipette because the pipette can be stuck directly into the organic layer bubble, meanwhile the culture tube has a round shape which makes gathering the organic layer more tricky because the pipette can go more off to the side and affect how much of the organic layer can be gathered. While this error did affect the results for the partition coefficient, it did not affect the interpretation of the