Benzoic Acid-Base Extraction

The purpose of this lab is to separate a 1:1 weight to weight mixture of Acetanilide and Benzoic Acid via Base Extraction and to purify a solid through recrystallization. Through IR, and NMR spectroscopy and by comparing melting points, we can determine the purity of the sample Figure 1: Chemical structure of Benzoic acid. Figure 2: Chemical structure of Acetanilide. The method of Base extraction uses the polarities of immiscible compounds to separate. Compounds are able to dissolve within each other because polar compounds are attracted to other polar compounds. This is created through dipole-dipole moments. The more electronegative atom has the greater number of electrons surrounding its orbit, creating a partial negative charge. The …show more content…
Since methylene chloride (CH2Cl2) is more denser liquid, it will drop to the bottom of a funnel and an organic layer is created. We turn an acid into a conjugate base with the addition of a strong base (NaOH). An acid is defined as a compound that can donate (H+) ions to a base. A base is defined as a compound that accepts (H+) from an acid. The strong base is able to deprotonate the acidic compound in the solution (benzoic acid) which can allow it to dissolve into the aqueous layer in this experiment. The strong base also creates an Acid-Base reaction that favors sodium benzoate as shown in (Figure 3). An acid is defined as a compound that can donate (H+) ions to a base. A base is defined as a compound that accepts (H+) ions from an acid. The concentration of the products divided by the concentration of the reactants (Equilibrium constant, Keq) is maintained at (Keq>1) by the inclusion of a strong base, NaOH. Consequently, since (Keq>1), it creates a good environment for extracting the …show more content…
When the ionic compound is in a mixture with water, the atoms that form the ionic compound can bind to the partial charges of water (H2O). This causes the ionic bond in the conjugate base to dissociate and allow the molecule to dissolve in water. The molecule can be separated from the water with the use of Methylene chloride (CH2Cl2). Methylene chloride is a compound much denser than water and allows the organic layer to sink to the bottom of a funnel, we benefit from this because we can extract the organic layer from the aqueous layer. In this case, acetanilide is soluble methylene chloride but, not soluble in water therefore, it will be extracted from the aqueous layer. Since benzoic acid is soluble in water, it will be in the aqueous (top)