Diethyl ether is considered a good organic extracting solvent because it has a low polarity, according to the University of Alberta's Organic Web Chem. When utilizing extraction solvents for liquid-liquid extraction, two solvents must be used; one is usually water or water-based, and the other an organic solvent. Because this process requires the second solvent to separate from water when combined, a non-polar solvent must be used.
In liquid-liquid extraction, water is almost always one of the two solvents used. Because the process requires that the two solvents do not form one substance, an immiscible second solvent is necessary. In chemistry, two substances are immiscible when they do not mix together if they make contact. Because water is polar, it will not create a single substance when it makes contact with a non-polar substance. Diethyl ether does not have different charges and chemical reactions at different points along its structure, so it is a non-polar organic compound. When it is used in this type of extraction along with water or a water-based solvent, the two substances do not form a single substance and instead separate. This allows liquid-liquid extraction to take place, and it makes diethyl ether and other non-polar organic solvents popular choices for scientists performing liquid-liquid extraction.