By using molar masses and these whole number molar ratios, it is also possible to calculate the theoretical yield of the reaction. The hydroxyl group reacts with acetic acid to form acetylsalicylic acid called aspirin which is the most widely common antiseptic and antipyretic agent. The temperatures for aspirin are. These are separate from dependent variables, whose name is derived from the fact that these variables depend on the independent variables. Conducted aqueous FeCl3 test on both the salicylic acid control and the aspirin. Remove excess water after filtering by pressing the water out with a stopper atop a piece of filter paper.
The experimental melting point range of aspirin was determined to be 122 -132°C. The boiling point isprobable at 3 000 0C. These independent variables are the amounts of Salicylic acid, Acetic Anhydride, water and any other substances used in the experiment, the temperature of the water used in the experiment, the time spent performing certain tasks, and any other variable that is controlled by the user. If you do not know what melting point to expect you will have to carry out a rough determination before determining the real melting point. When you can prove that your measuring set is proper one and measurement is well performed, increased Mp is worthy of further investigation and publishing of results. Mixture Melting Points Abstraction Determining the melting point is very significant in order to identify an unknown.
While the ester can be formed from acetic acid and salicylic acid, a better preparative method uses acetic anhydrides in the reaction instead of acetic acid. The mixture was warmed over a water bath for 5 minutes while stirring. I work in the lab and our vacuum is not working at optimum efficiency, therefore, it takes longer to dry any sample. This is a condition which results in destruction of some or all of the in the kidneys. Acetic acid and phosphoric acid are water soluble so they were removed by washing the aspirin with chilled water. They are effective in the relief of pain and fever. In 1897, Felix Hoffmann discovered that there was indeed a way to make this drug less irritating to the throat and stomach: by reacting Salicylic acid with Acetic Anhydride, it would be possible to acetylate the Salicylic acid to remove one of these proton-donating groups and thus make it less irritating to the body.
By replacing the arbitrary large amount of substance that was on the balance at first, it is then possible to view the total amount of substance removed from the large arbitrary amount and is, consequentially, in the desired receptacle. Aspirin has analgesic, antipyretic and platelet-inhibitory properties. It is applied in the production of liquid crystal polymers. My question is what would have caused us to have a high percent yield, but low purity? It has the ability to reduce fever an antipyretic , to reduce pain an analgesic , and to reduce swelling, soreness, and redness an anti-inflammatory agent. After this, lightly stir the crystals for another 5 minutes, again with the water aspirator on. Bring the solution to a boil quickly and limit the amount of time you are boiling the crystals in the solvent 9. The unknown solid was confirmed to be Salicylic Acid, a compound with a melting range between 158-159 degrees Celsius.
Introduction Organic compounds are a certain type of compounds that contain carbon. Retrieved 23 April 2011: Theoretical Yield and Useful Nomenclature. In determining the melting point range of the aspirin, a capillary tube sealed at one end was one-third-filled with the dried aspirin. It should also be kept out of the way of children and animals. An impure compound melts over a wider range of temperatures, usually greater than 2 degrees. The organic molecule actually synthesized in this experiment is Acetylsalicylic Acid, commonly known as Aspirin. Fill a cuvette with distilled water to act as a calibration constant, and then rinse another cuvette with the solution 3 times before filling it with the Aspirin solution.
It is an ideal compound for this type of research. The theoretical yield was 2. The melting point helps to identify unknown samples, narrowing the number of possibilities, because a pure solid melts reproducibly over a narrow range of temperatures. It is used to help reduce pain and swelling, but there are also a few side effects that may occur. The bottom of the melting range is the temperature at which the first signs of liquid can be seen. Then, it is released into the blood stream and has pain-relieving effects How much of the reagents should you use? C Hippocrates documented that extract from the bark of the willow tree Salix genera could be used as a remedy for fever, pain, and inflammation, though evidence suggests that people knew about its effects long before.
Many different laboratory techniques are used in the synthesis of Aspirin. If it is the former, how did you proceed? The mechanism of the reaction is more complicated than this, however. Almira Department of Pharmaceutical Chemistry, College of Pharmacy University of the Philippines Manila The Health Sciences Center Valenzuela Hall, Taft Avenue, corner Pedro Gil St. By calculating the theoretical yield based on the original amount of Salicylic acid, one could determine the actual yield percentage of the reaction. This resulting compound, Acetylsalicylic Acid, was trademarked by the Bayer as Aspirin®. In this case, the melting point was 143°C whereas the true meling point is 135°C. I thought one of the reasons my melting point could of elevated is due to impurities from contaminated equipment or the chemicals being in equalibrium causing sailcylic acid to remain in the final product.
The main purpose of this laboratory is to obtain aspirin through the chemical synthesis of salicylic acid by acetylation with acetic anhydride and crystallization. The erythrocytes are then lysed when the complexes activate the. Felix Hoffman was the first to perform this experiment. Aspirin comes in white monoclinic tablets or as a crystalline powder. Physicians suggest that aspirin may reduce the risk of a heart attack. Aspirin has a bitter taste.
This is partially because of the fact that Salicylic acid is a diprotic acid; this means that when Salicylic acid dissolves in water, it releases two Hydronium ions and makes the solution more acidic than if the same number of a monoprotic acid molecules were added. Once it is a liquid, the boiling point is the temperature that the vapor pressure of the liquid is large enough that bubbles form inside the body of the liquid. Take this Salicylic acid to a fume hood, along with both graduated cylinders, the wash bottle filled with distilled water, the medicine dropper, and a 150 mL beaker to hold distilled water. Date: July 4, 2013 Melting point Different organic compound with their melting point range was listed to confirm the identity of the Capillary tube unknown. Chlorine Melting point is 172 Kelvin which is also its freezingpoint Chlorine's boiling point is 239 Kelvin which is also itscondensing point For reference, water freezes at 273 Kelvin and boils at 3 … 73 Kelvin. The first of these is the concept of a limiting reactant.
It contains both a hydroxyl and a carboxyl group, which react with either an acid or an alcohol. Back Titration: Back titration is an analytical chemistry technique that allows the user to find the concentration of a reactant of unknown concentration by reacting it with an excess volume of another reactant of known concentration. This experiment also taught the importance of diligence and following directions carefully. If it is the former, how did you proceed? One of the first recorded accounts for the discovery of aspirin appeared in England, in 1763, crediting the bark of willow trees with a beneficial effect in alleviating distress due to fevers, aches, and pains. This initial crystallization can be induced by scratching the side of the beaker: such scratching will dislodge tiny glass particles that can be used as templates to start the crystallization process.