Dispose the filtrate it the appropriate waste container. Heating was done to melt the salicylic acid for it to be able to react with the acetic anhydride. The phenol group in salicylic acid is replaced by a carboxyl group through electrophilic substitution. Conclusion The hypothesis of making a reasonably pure sample at a relatively high efficiency stayed mostly true: though not medicinal quality, a purity of 97. In the presence of Hydronium, the negatively charged oxygen shares electrons with a hydrogen from the reagents. Lab Report Synthesis and Characterization of Aspirin Acetylsalicylic Acid The Synthesis and Characterization of Aspirin Acetylsalicylic Acid.
Unknown compound C was the only unknown that underwent a color change when treated with iodine solution, meaning compound C was determined to be ground aspirin tablet even though there was some concentration of phenol present. In 1763, the Reverend Edward Stone introduced these extracts and teas to the Europeans and in the early 1800's the active ingredient in willow bark and in the flowers of the meadow sweet plant which had similar therapeutic characteristics was isolated and identified as salicylic acid from salix, the Latin name for the willow tree. Cold water, on the other hand, is used to recrystallize only aspirin, thus, leaving all the impurities behind. The purity of the aspirin is determined by melting point determination and infrared spectroscopy. While many variables can change in the experiment, there are many variables that are independent controllable as well. The first portion of the experiment seemed to be a practice 10 fold serial dilution using the chemical bromophenol blue, and was treated as a quantitative experiment.
The water bath temperature should not exceed 50 degrees Celsius. Heat the mixture for 5 minutes. Purify the rest of the aspirin by recrystallization. The elapsed time was noted and recorded. This could be rectified by using a greater amount of Salicylic acid and Acetic Anhydride in the beginning of the experiment.
If the geometry of the molecule fits that of the crystal, it will be more likely to remain on the crystal than it is to go back into the solution. The present experiment will be the synthesis of a familiar organic compound called aspirin. The final product aspirin percent yield was 18. Crystals appeared shiny, clear, and needle-like 11. Weigh a clean, dry, 125 mL Erlenmeyer flask with a rubber stopper and record its mass. Answer the following post-lab question: If 0.
On the other hand, water was added after heating not at the start of the experiment. The purified product started to melt at 86 degrees Celsius and finished completely melting at 102 degrees Celsius. If crystallization does not occur use a glass stirring rod and with strong force scratch the bottom of the Erlenmeyer flask. The aspirin is allowed to dry, weighed, and then the percent yield is calculated. Though the experiment proved the hypothesis to stay true, several improvements could have been made to the procedure.
The triphenylmethanol was purified by recrystallization. Observe the color: Pure aspirin would show no color, while salicylic acid or traces of it in impure aspirin will show a purple color. The amount of each compound should be the same because there is a 1:1 ratio between them. The temperature of an alcohol thermometer was equilibrated in a beaker of room temperature tap water. It is important to note, however, that the standard deviation of the sodium acetate — catalyzed reaction 31. The equilibrated thermometer was immediately placed into the reaction solution and the initial temperature on the thermometer was noted. This might explain the large data spread.
This polymer was not transferred to the solution with water, reducing yield. Another area in which the experiment could be improved upon is the drying: rather than simply letting the product sit in the crucible to dry, it is possible to stir it constantly in order to help release any trapped liquid escape. Joseph Aspirin, and many generics. Heat it for fifteen minutes with occasional stirring. Aspirin originally was derived by boiling the bark of the white willow tree. Aim: To prepare aspirin from salicylic acid. It is effective in reducing pain it is an analgesic , reducing inflammation anti-inflammatory , reducing fever antipyretic , and thinning blood anti-coagulant.
The reaction yield may be improved by adjusting the amount of reactant or product in the reaction. Substituting Lewis structures for molecular formulas in chemical reactions provides more information. In the 5th century B. Be sure to use a water bath that is large enough for any bubbles which form in the water to easily pass around the Erlenmeyer flask you are heating. Salicylic acid could be modified to produce phenylsalicylate, which was better tasting and less irritating, but released the toxic substance phenol when metabolized.
The melting point of the crystals was determined to be 133-136 oC, which is within the reported literature range and supports the identity of the desired reaction product. Aspirin was originally derived from the active ingredient in willow bark called salicin and was first synthesized chemically in 1897. To most directly measure rate, the concentration of a product should be measured periodically over time. Cool the Erlenmeyer flask containing the mixture in the ice bath set up previously for 20 minutes. Collected crystals by vacuum filtration again.
As no experiment is perfect, the yield percent will always be less than 1. Isolation was done through suction filtration, white, sugar-like crystals were obtained. Be sure the water is near freezing to minimize loss of product. The melting point of pure acetylsalicylic acid is 135 ˚C 1. The objective was to convert a specific amount of salicylic acid into the same amount of aspirin that was high in purity. This subset of variables is completely different from the things that remain constant in the experiment: regardless of anything else that happens, water will always have the same absorbance, all chemicals used will have the same molecular mass, density, melting point, and other physical quantities, and the equipment used in the experiment will always act the same way.