Separating Acids and Neutral Compounds by Solvent Extraction
Separating Acids and Neutral Compounds by Solvent Extraction
Introduction
The purpose of this experiment was to use solvent extraction techniques in order to separate a mixture consisting of a carboxylic acid (p-toulic acid), a phenol (p-tert-butylphenol), and a neutral compound (acetanilide). Extraction is the process of selectively dissolving one or more of the compounds of a mixture into an appropriate solvent, the solution that contains these dissolved compounds is called an extract (Manion, 2004). Impurities that are present in the solution can be removed by extracting them from the original solvent into another solvent. This is done by mixing two immiscible (insoluble to one another) solvents (Manion, 2004). By mixing the solvents together rapidly the exchange of the desired product from one solvent will be transferred to the other and the impurities remain in the original solvent. The two solvent layers then completely separate from each other as they are immiscible. The process washing is the reverse process, it leaves the desired compound in the original solvent and the impurities are transferred to the second solvent (Manion, 2004). The solvent selection generally is determined by polarity, on will be polar typically wathe while the other a non-polar solution (hydrocarbon). The solvent choices that are used will always separate as they are unlike molecules and will not be able to be dissolved into each other. The result is a layering effect of the solvents within the container they are held, the denser layer of the mixture will always appear at the bottom of the container. This phenomenon allows for quick identification of the layers within the experiment with a water drop test indicating which of the solvent take on the water is the aqueous layer. If one of the compounds in the mixture can be converted into its ionic form it can be more easily extracted into an aqueous layer as it becomes soluble within the solvent (Manion, 2004). By
Introduction
The purpose of this experiment was to use solvent extraction techniques in order to separate a mixture consisting of a carboxylic acid (p-toulic acid), a phenol (p-tert-butylphenol), and a neutral compound (acetanilide). Extraction is the process of selectively dissolving one or more of the compounds of a mixture into an appropriate solvent, the solution that contains these dissolved compounds is called an extract (Manion, 2004). Impurities that are present in the solution can be removed by extracting them from the original solvent into another solvent. This is done by mixing two immiscible (insoluble to one another) solvents (Manion, 2004). By mixing the solvents together rapidly the exchange of the desired product from one solvent will be transferred to the other and the impurities remain in the original solvent. The two solvent layers then completely separate from each other as they are immiscible. The process washing is the reverse process, it leaves the desired compound in the original solvent and the impurities are transferred to the second solvent (Manion, 2004). The solvent selection generally is determined by polarity, on will be polar typically wathe while the other a non-polar solution (hydrocarbon). The solvent choices that are used will always separate as they are unlike molecules and will not be able to be dissolved into each other. The result is a layering effect of the solvents within the container they are held, the denser layer of the mixture will always appear at the bottom of the container. This phenomenon allows for quick identification of the layers within the experiment with a water drop test indicating which of the solvent take on the water is the aqueous layer. If one of the compounds in the mixture can be converted into its ionic form it can be more easily extracted into an aqueous layer as it becomes soluble within the solvent (Manion, 2004). By
Cited: Manion, J. 2004. University of Central Arkansas. Separating Acids and Neutral Compounds by Solvent Extraction. In: Signature Lab Series Chemistry Labs. (M. Stranz, editor) Cengage Learning. Mason, Ohio. 2008. Pp.45-63.