PREPARATION OF ASPIRIN AND
DETERMINATION OF THE MELTING POINT
Ferrer, Lara Melissa V.
Faculty of Engineering
University of Santo Tomas
Manila, Philippines
ABSTRACT
This experiment involved three steps: synthesis of aspirin, isolation and purification, and the estimation of purity of the final product. The synthesis involved the reaction of salicylic acid and acetic anhydride in the presence of a catalyst, phosphoric acid, H3PO4. When the aspirin was prepared, it was isolated and filtered. The percentage yield of the synthesis was calculated to be 78.42%. The experimental melting point range of aspirin was determined to be 122 -132°C. Due to its wide range, and lower value than that of the theoretical melting point of 136°C, it was
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Salicylic acid is also used in a variety of other personal care items such as dandruff shampoo, antiseptic and toothpaste. [2] METHODOLOGY
3.0g of salicylic acid was weighed then 3.0mL of acetic anhydride and 6 drops of 85% H3PO4 were added to it. The mixture was warmed over a water bath for 5 minutes while stirring. After warming, 20 drops of distilled water was slowly added. 15mL of water was added then the solution was heated until it became clear. It was allowed to cool and was placed in an ice bath until the solution becomes cloudy. Using pre-weighed filter paper, the mixture was filtered and was allowed to dry in the filter paper.
In determining the melting point range of the aspirin, a capillary tube (sealed at one end) was one-third-filled with the dried aspirin. The capillary tube and a thermometer were immersed in an oil bath. The temperature at which the solid started to melt and the temperature when the entire sample was completely liquefied were recorded as the melting point temperature range.
DISCUSSION OF DATA AND RESULTS
Aspirin was synthesized by reacting salicylic acid with acetic anhydride in the presence of phosphoric acid, H3PO4, as a catalyst:
The aspirin was synthesized when it was placed in a cold bath. Purification was necessary to remove any unreacted salicylic acid and acetic anhydride as well as the acetic product and phosphoric acid. Acetic acid and phosphoric acid are water soluble so they were removed by
Ever wonder about the chemical makeup of tablets that people take for pain relief? Before a tablet can be successfully made, the limiting and excess reactants must be considered. The limiting reactant will affect the amount of the product that can be made. Another reason why the starting reactants must be determined carefully is to make reduce the amount of the reactant in excess so that reactants are not wasted. This experiment uses an Alka-Seltzer tablet. Alka-Seltzer dissolves in water and is an antacid and a pain reliever1. The Alka-Seltzer tablet has many uses such as relief of headaches, ingestion, heart burns, or even upset stomachs2. The active ingredients in an Alka-Seltzer tablet is aspirin, also known as acetyl-salicylic acid (C8H12O4), citric acid (C6H8O7), and sodium bicarbonate (NaHCO3)2. The aspirin in the Alka-Seltzer tablet helps with pain relief. Because of the acid-base chemistry (Brønsted-Lowry), citric acid and sodium bicarbonate produce O2, which makes the tablet fizz when it is dropped in liquid. The Brønsted-Lowry theory shows how the Brønsted-Lowry acid donates a hydrogen ion while the Brønsted-Lowry base accepts the hydrogen ions3. The remaining NaHCO3 that is in excess post reaction with the citric acid is what is used to neutralize stomach acid which helps relief heart burn2. The problem in
In experiment two, the drug Panacetin was separated by a series of chemical reactions into its three components: sucrose, aspirin, and an unknown active ingredient, either acetanilide or phenacetin. The purpose of this lab was to determine what percentages of each component is present in the pain-killer. The initial step was to dissolve Panacetin in dichloromethane. However, sucrose is insoluble in dichloromethane because organic molecules are soluble in organic solvents, and dichloromethane is an inorganic solvent, so only aspirin and the unknown dissolved. By using gravity filtration, sucrose was filtered from the solution and 0.30g of solid was collected.
Both Aspirin and the Unknown are soluble in dichloromethane, due to their non-polar characteristics. To separate the two components, sodium bicarbonate was added (see figure 3). Sodium bicarbonate reacted with aspirin and converted it to a salt, also forming water and carbon dioxide. It was observed that the solution "fizzed" when this reaction took place, showing the release of carbon dioxide. The newly formed salt then traveled to an aqueous layer where it was soluble, while the unknown remained in the dichloromethane layer. The two layers were then separated. To collect an aspirin solid, the combination of the addition of HCl and the process of vacuum filtration helped to break down the salt and form a solid. Then the solid was placed in the Fisher Scientific Biotemp Oven to dry it to a constant mass of 0.091 g, 32.97% of the total composition. The
Melting Point Data Table Compound Aspirin Caffeine Salicylamide Actual MP (ºC) 93 - 98 260 - 262 96 - 102 Expected MP (ºC) 135 236 140 Percent Error (%) ~30% ~12% ~30%
The goal of this experiment was to find out active chemical components in Anacin and Tylenol, using Thin Layer Chromatography technique. This technique uses the difference in the intermolecular forcer and polarity to separate mixtures. Comparing Rf values were then used to determine the active chemical components in the two analgesics. The overall result was that Acetaminophen exists in Tylenol and Acetylsalicylic Acid exists in Anacin.
Industrial production of Aspirin is dependent on the company producing the drug; however the general method of production is known as slugging or dry-granulation. In this method, corn starch is mixed with pure water and is then heated and
Separation and Purification of the Components of an Analgesic Tablet. Cora Bruno, Lab Section E. Aspirin, Caffeine and Acetaminophen were separated from four analgesic tablets of Excedrin using extraction techniques. 5% wt/vol NaHCO3, 4M HCL, ethyl acetate and deionized water were used to separate the three active components. MgSO4 was used to dry each extraction. Aspirin was isolated using a hot water bath and weighed to determine the percent theoretical recovery and the actual percent recovery of aspirin. After separation, Aspirin (ASA), Caffeine (CAF), and Acetaminophen (ACE) were purified and identified using Thin Layer Chromatography (TLC). Standards and purified ASA, CAF, and ACE were spotted on the silica gel (stationary phase) of the
Acetic Anhydride and p-Aminophenol were heated in a vial attached to an air condenser to synthesize crude acetaminophen, resulting in 0.097 grams (47.48% yield). The crude acetaminophen was then recrystallized in a solvent of water and methanol over heat resulting in 0.082 grams (39.61% yield) of pure acetaminophen. Melting points of both crude and pure acetaminophen were taken, and found to be 165.9 - 170.9°C and 168.2 - 171.5°C, respectively. The literature melting point of acetaminophen is 169.5 – 171.0°C, indicating that our final product was pure.
The objective of this lab is to synthesize acetaminophen from p-aminophenol. The techniques used to do so, consist of: reflux with heat to allow reaction to occur at a reasonable time period, extraction and filtration to isolate the desired product, and characterization of the product by analyzing IR spectras and melting points. Acetaminophen considered synthesized, primarily due to the IR spectrum exhibiting all the bond vibrations is the amide group. The percent yield of 124.6% imply that there was a mechanical error that occurred, thus, also tampering with the progression of the chemical reaction. The wide melting point range of 165 C-169 C denote the impurity of the acetaminophen product.
The goal of the experiment was to securely isolate pure acetaminophen from p-aminophenol using a synthesis reaction. Synthesis still remains an important tool for scientists conducting chemical reactions. Most synthesis relies on a long process that involves multiple chemicals reactions. In the synthesis of Acetaminophen, one reaction is performed and a four step process is used, Scheme 1. Multiple techniques was used to achieve this goal.
Aspirin also known as acetylsalicylic acid is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an
The purpose of the lab was to synthesize aspirin and oil of wintergreen, and to determine its purity using recrystallization process, determining its melting point and using back-titration. To synthesize aspirin, salicylic acid and anhydride was used to drive the reaction to completion. In the synthesis of oil of wintergreen we reacted salicylic acid and methanol to produce methyl salicylate. This reaction is an example of a condensation reaction where the carboxylic acid and alcohol group combine to form an ester. In producing aspirin, we wanted to obtain the purest form, so we removed impurities such as unreacted salicylic acid and acetic acid. Acetic acid was removed by rinsing the sample in water because acetic acid is soluble in water. Salicylic, however, was removed by using the recrystallization process because it is insoluble in water. To recrystallize, we dissolved a sample of crude aspirin in warm ethanol and let it cool. Because aspirin is less soluble in ethanol than salicylic acid, it will crystallize out of the solution. To obtain the purified aspirin sample, we then filtered the solution to separate it from the impurities. To determine qualitatively the purity of the recrystallized aspirin, we determined its melting point using a melting point apparatus. Using the idea of freezing point depression, the presence of impurities will lower the melting point of the substance. Thus, by comparing the melting point to the actual
0.1 gram of commercial aspirin was weighed in a tray and was then added to a second test tube containing 2.0 mL of Iron (III) chloride, which was measured using a 10 mL graduated cylinder, to test for phenols. This was repeated once more to validate results.
The goal of this experiment was to synthesize aspirin. In this experiment aspirin, also known as acetylsalicylic acid, was synthesized from salicylic acid and acetic anhydride. In the reaction the hydroxyl group on the benzene ring in salicylic acid reacted with acetic anhydride to form an ester functional group. This method of forming acetylsalicylic acid is an esterification reaction. Since this esterification reaction is not spontaneous, sulfuric acid was used as a catalyst to initiate the reaction. After the reaction was complete some unreacted acetic anhydride and salicylic acid was still be present in the solution as well as some sulfuric acid, aspirin, and acetic acid. Crystallization, which uses the principle of
During the 1890s Felix Hoffman a chemical engineer who worked at the Bayer Company located in Germany was looking to help his father who was suffering from arthritis. He discovered how to isolate acetylsalicylic acid in a digestible form.. Starting in 1899, the Bayer company began to sell an aspirin powder to doctors to provide to their patients. The drug became a hit and, in 1915, it was sold as over-the-counter