Why multiple extractions

Request an Appointment. Home About Todd K. Home About. Todd K. Though saving the original structure is ideal, we may have to extract the tooth if there is insufficient tooth structure to save. Bone loss in the jaw can occur and then there is insufficient bone to support your teeth.

When this occurs, bacteria can leak through the cracks and cause infection. Sometimes, the fracture is significant enough or positioned in such a way that we can not restore the tooth and the tooth needs to be extracted. A bridge uses either natural teeth or dental implants to permanently anchor false teeth between.

Add another fresh 20 mL of diethyl ether to the separatory funnel and extract the aqueous solution one more time. Save both liquids. Add just enough anhydrous magnesium sulfate a drying agent to barely cover the bottom of the Erlenmeyer flask. Swirl the contents gently, and allow the flask to stand for at least 15 minutes. Magnesium sulfate is insoluble in diethyl ether but is very soluble in water. If the drying agent remains undissolved after 15 minutes, then discard the aqueous solution still in the mL beaker down the drain.

If you are uncertain, check with the instructor. Set up a simple distillation apparatus with a mL r. Use a mL Erlenmeyer flask as the receiver. Remove the thermometer and adapter from the assembly and place along-stem funnel in the still pot. Insert a small plug of absorbent cotton at the top of the funnel stem. Carefully decant the ether solution from the drying agent through the funnel into the flask.

Rinse the Erlenmeyer flask with about 10 mL of ether and pour the ether through the funnel, too. Remove the funnel, add two or three boiling chips and reattach the thermometer and adapter to the still pot.

Discard the magnesium sulfate remaining in the Erlenmeyer flask by dissolving it in tap water and pouring the solution down the drain. Before beginning the distillation, weigh a clean, dry 1 oz narrow mouth screw cap bottle on a balance.

Remove the cap of the bottle, and insert the clean, dry plastic long-stem funnel in the neck of the bottle. Set aside until needed. Slowly distill the ether from the solution. The normal b. The temperature will gradually rise, however, because some propionic acid vaporizes along with the ether.

Eventually, the distillation appears to stop no liquid is delivered from the end of the condenser. When the still head temperature rises above o , discontinue heating. How much hyoscyamine would be extracted with this method? The calculation for the third extraction is as follows:. The results of the calculations in this section are summarized in Figure 4.

These calculations demonstrate that using multiple portions of a solvent maximizes the extractive power of the solvent.

In general, three extractions are the optimal compromise between expended effort and maximizing the recovery of material. Nostrand Company, Lisa Nichols Butte Community College. Complete text is available online. Table 4. Quantitating Single Extraction Hyoscyamine is an alkaloid from a plant in the nightshade family Figure 4.

Multiple Extractions Overview of Multiple Extractions Depending on the partition coefficient for a compound in a solvent, a single extraction may be all that is needed to effectively extract a compound. The location either the top or bottom layer of an extraction solvent is determined by density. The density of ether is 0. When two immiscible liquids are placed in the separatory funnel two phases are observed as discussed above. As mentioned before, the fundamental reason for carrying out an extraction is to isolate a compound from a mixture.

For example, consider a mixture consisting of 2 polar compounds and 1 nonpolar compound. After extraction with the solvent pair of ether and water, the 2 polar compounds would be found in the aqueous layer a polar solvent dissolves a polar solute and the nonpolar compound would be found in the nonpolar phase ether.

Note: the phase consisting of H 2 O is called the aqueous phase. As a result, the nonpolar compound is isolated from the mixture. See the extraction scheme below. The idea that a compound dissolves more or less readily in a solvent can be quantitated by the distribution coefficient : which says there exists a ratio of the concentration of the solute between the two phases given the solvent pair and temperature. This coefficient is discussed further in recitation.

Two phases should be observed. Place the cap on the separatory funnel. Holding the cap and funnel securely, invert the separatory funnel. Vent the separatory funnel: with the funnel inverted and cap secured , open the Teflon stopcock to reduce any pressure that has built.