Butyric acid is a colorless liquid with a characteristic odor and is a monocarboxylic acid with four carbons in its molecular formula. It is used in food additives, preservatives and pharmaceuticals industry. Butyric acid is also known as "butter acid" because it is present in butter at about 2-3%. It has a moderate degree of acidity, resulting in an undesirable odor of spoiled butter as a result of hydrolysis in glycerin. As in most carboxylic acids, butyric acid should be separated from the aqueous medium at the end of the production. Evaporation of the water by distillation brings with high energy costs. In addition, requiring a column with many stages for effective separation increases the cost of construction.
Therefore, the liquid-liquid extraction method is frequently preferred for the recovery of carboxylic acids from dilute solutions. For this method to be successful, a suitable solvent should be selected to separate the mixture, the choice of solvent as a more environmentally friendly solvent was proposed.
In this study, dibasic esters mixture were used as solvents for determining the ternary liquid phase diagrams of aqueous mixtures consisting of butyric acid, to bring more effective and environmentally friendly solvents into use. In accordance with this purpose, liquid – liquid phase equilibrium of Water – Butyric Acid – Dimethyladipate/Dimethylglutarate /Dimethylsuccinate (16:63:21 %w), Water – Butyric Acid – DBE 6 and Water – Butyric Acid – DBE 9 were investigated at 298.15 K and atmospheric pressure. The ternary phase diagrams composed of solubility data and tie-lines were presented graphically. The reliability of the experimental tie-lines was ascertained by Othmer–Tobias correlation method.
Anahtar Kelimeler: Butyric acid, dibasic esters mixture, liquid–liquid equilibria, Othmer–Tobias correlation
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