Chemistry Lab Liquid-Liquid Extraction
Experiment Date: 2/19/10
Due Date: 2/26/10
The goal of this lab was to determine the amount of impurity, in the form of oil, in water using the method of solvent extraction, also known as liquid-liquid extraction, a method of separating two materials with different physical and/or chemical properties. Two methods of evaporation will be used to finally determine the concentration of impurity- one using an explosion-proof hot-plate, and one using a rotovap.
Fig. 1a+1b. Figure 1a shows how water and oil separate in the separatory funnel, while figure 1b shows the actual apparatus. Liquid-Liquid extraction is a versatile and dependable separation technique wherein an aqueous solution is usually brought into contact with another organic solvent, exclusively immiscible with the former, so as to affect a legitimate and actual transfer of either one or more solutes into the latter. Separations technique is superior to others due to ease of use, faster extraction times, decreased volumes of solvent, and their superior ability to concentrate the analytes. Invariably such separations may be performed by shaking the two liquids in a separatory funnel for a few minutes; and may be extended either to large quantities of substances or trace levels. Liquid-liquid extractions are usually accomplished with a separatory funnel. The two liquids are placed in the separatory funnel and shaken to increase the surface area between the phases. When the extraction is complete, the liquids are allowed to separate, with the denser phase settling to the bottom of the separatory funnel.
Solvent Extraction is basically a process of diffusion of a solvent into oil-bearing cells of the raw material resulting in a solution of the oil in solvent. Various solvents can be used for extraction. However, after extensive research and consideration of various factors, such as physical properties of