BUFFER SOLUTION BEHAVIOUR ON SOLUBILITY AND DISTRIBUTION COEFFICIENT OF BENZOIC ACID BETWEEN TWO IMMISCIBLE LIQUIDS

The two immiscible solvents such as hydrophilic (water) and hydrophobic (benzene) have been reported for study of solubility and distribution of benzoic acid in it. The solubility of benzoic acid in water and in different acidic, neutral, and basic pH benzene-buffer solutions are analyzed by titrimetrically, and concentration of acid in both solvents by acid-base titration method. The shake-flask method are involved for where the partitioning or distribution coefficient of benzoic acid in these two solvents layer at room temperature (25°C). Observation reveals that, the benzoic acid solubility in g/100g for water is being 0.142±0.033 and at different buffer solutions with pH 4.0, 7.0 and 9.0 it being 0.153±0.012, 0.186±0.145 and 0.148±0.708, in respect of partition coefficient of that acid where it for water-benzene solvent as 0.636 and in buffer solutions is being 0.841, 0.624 and 0.589 respectively. In graphically, at different pH buffer solutions the solubility plot of acid in neutral pH (7.0) is higher than other acidic and basic, but it for distribution coefficient of acid in acidic (pH 4.0) medium is higher than both neutral and basic pH (9.0) medium.