Use of acidity in separations

The pKa is important since it affects the way certain phenolic compounds are extracted. If we consider having a mixture of phenols that range from weak acids to strong acids, the addition of sodium carbonate (Na2C03) or sodium bicarbonate (NaHC03) to the mixture will allow separation of these phenols. The weak base picks up the H from the strong acids or the more acidic phenols. This results in formation of phenolate salts of the phenols that are soluble in water. 

The less acidic phenols are not neutralized or do not lose a fT and tend to remain as free phenols and will not be as soluble in water. These compounds can then be extracted with organic solvents. 

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