Anthracene Solubility

An Erlenmeyer flask was used to accommodate the largest volume of recrystallization solvent calculated and was cooled in an ice bath to increase the yield of crystals. The solid was collected by vacuum filtration and washed with a small amount of ice water. The product is then dried to a constant mass by use of an oven and weighed. A small amount of the unknown was compared to two samples of acetanilide and phenacetin for a melting point range to determine the identity. The temperature of the unknown was recorded when the first trace of liquid can be seen and when the unknown was completely liquid.

Phenacetin’s cold water solubility is 0.076 grams/100 mL of water, whereas its boiling water solubility is 1.22 grams/100 mL of water. In this experiment, water solubility will be an indicator for how much boiling water to use in recrystallization, which purifies the unknown precipitate produced in the second lab. If a substance has higher water solubility in boiling water, such as acetanilide compared

During recrystallization, the solution was to be cooled to room temperature before placing it in an ice bath. Doing this allows enough time for the crystals to be formed because as the temperature decreases, the rate of crystallization slows down. If the solution was placed in the ice bath too quickly, then the cold would have blocked out the impurities and trapped them in the solution. The more impurities present, the lower the melting point so data would have been inaccurate. Also, if the melting point apparatus wasn’t set up correctly, the data would have been imprecise.

Recrystallization is a technique frequently used in organic chemistry to purify solid organic compounds. The goal of this technique is to allow organic compounds to form crystal lattice structures, and to remove any of the impurities that do not align within this crystal structure.1 The theory behind recrystallization revolves around entropy; as heat will cause a organic compound to dissolve (increase in entropy), a decrease in heat will then allow that organic compound to reform (decrease in entropy) and become purer.2

The mixture was heated at 120°C using an aluminum block and was stirred gently. After all of the solid dissolved, it was heated for 20 additional minutes to ensure the reaction was complete.

21) After all of the solid dissolves, move the flask from the hot plate and allow it cool to room temperature. After a while, crystals should appear in the flask.

The product was then suspended in 2 ml of water with a stir rod in a 50 ml Erlenmeyer flask and heated to boiling. Water was added in one milliliter increments until all the product was dissolved (18 ml added total). The saturated solution was allowed to slowly cool, and gradual white crystal formation was observed. Recrystallized product was collected once more by suction filtration with the Hirsch funnel once crystallization ceased. Collected product dried on a watch glass for a week, weighed 0.14 g (1.2 mmol), and the melting point was 139°-141°

6. The solubility of the solids were tested using a micro tray, by placing them in water and oil to observe their polarity,

Recrystallization purifies a crude product by separating the product from impurities based on solubility. The product being purified should easily dissolve in the chosen solvent at high temperatures, but not at room temperature. Impurities should dissolve in the solvent at room temperature but not at high temperatures.

Crystallization was induced in the solution by scratching the inside of the beaker with a glass stir rod. 2. Next, an ice bath was made by partially filling a 400 mL beaker with ice and covering the ice with water. 3. The beaker containing the solution was then placed in the ice bath for approximately 15 minutes.

To be able to complete this experiment various lab instruments were needed. This includes the use of beakers, test tubes, a metal spatula, wooden splints, and a Bunsen burner. The analysis begins with determining the physical traits of the compound. Then 0.15 grams of the unknown substance is mixed with 3 mL of distilled water to test

The 20ml beaker was washed with dichloromethane to collect the solid left in the beaker. The filtered solution was collected in the 25ml filter flask. Then, the filtered solution was transferred to a clean centrifuge tube and the solid compound was transferred to a clean test

The colorless solution was poured into a beaker containing 10mL of chilled water, after the designated time, to initiate recrystallization for 5-10 minutes. 9. The nitrated methyl benzoate solution was then poured onto the filtrating apparatus and left to dry for 10 minutes. 10. The white, dried crystals were weighed and dissolved in ethanol then filtrated again and

The solution is then cooled and recrystallization of the solute occurs. For a solvent pair to

If the solute melts prior to the boiling of the solvent, recrystallization will not be able to occur. For example, if you wanted to purify a sample of Compound X which is contaminated by a small amount of Compound Y, an appropriate solvent would be one in which all of Compound Y dissolved at room temperature because the impurities will stay in solution and pass through filter paper, leaving only pure crystals behind. Also appropriate would be a solvent in which the impurities are insoluble at a high temperature because they will remain solid in the boiling solvent and can then be filtered out. Finally, the solvent should be volatile enough as to evaporate from the surface of the compound and be of low financial cost.