Experiment #5 – Aspirin Synthesis Lab Report

.pdf

School

Wilfrid Laurier University *

*We aren’t endorsed by this school

Course

110

Subject

Chemistry

Date

Feb 20, 2024

Type

pdf

Pages

Uploaded by DeaconSnow11815

1 Abstract The purpose of this lab is to synthesize aspirin from the mixture of acetic anhydride and salicylic acid. This resulted in creating crystals and used to filter in the Hirsh funnel. Creating a vacuum when pouring the liquid will allow the solid to be trapped when the liquid gets drained. This filtered product was impure and solid acetylsalicylic acid, with a mass of 0.12g. The melting point of this ASA was determined and compared with the standard ASA. This was done using a Digimelt melting apparatus which involved placing the solid in a capillary tube into the machine to find an accurate melting range. The initial melting point of Asa was 102.3 ℃ and final readings of 105.7 ℃ . The prepared ASA was involved in the Iron (III) salicylate dianion solution with NaOH. The diluted sample was mixed with FeCl. A vernier Go Direct calorimeter was used to measure the absorbance of 5 standard solutions and construct the Beer’s law plot graph. The mass of pure ASA and concentration values were determined. Also, the percentage purity was calculated as 99% and percentage yield of 34%. This means that only 34% of aspirin was synthesized out of 100% and the aspirin was 99% pure. In conclusion, this experiment was not successful due to low percentage yield. Procedure For the procedure, see lab manual (CH110 Lab Manual, Fall 2023) pages 121-124. No deviations were made to this aspirin synthesis experiment. Wilfrid Laurier University Chemistry Department. Fall 2023. Pages 117-127 in the Chemistry 110 Lab Manual. Wilfrid Laurier University, ON, Canada Observations/Results Table 1: Before, During, After Qualitative Observations of Solutions From Part A-E Part Solutions

2 A Salicylic Acid: white, odourless powder Phosphoric Acid: clear, yellow, transparent liquid Acetic Anhydride: clear, liquid, vinegar odour DI water (4 drops): some liquid but solid particles formed DI water (7 drops): white crystal-like solid participles at bottom of tube B Prepared ASA Before: wet, cloudy particles, viscous Prepared ASA After: sand like texture, odourless, white, solid C Standard ASA sample Before heat: small, dry solid, white, very grainy, After heat: clear, colourless, liquid Prepared ASA sample Before heat: powder texture, grainy, opaque, solid, white After heat: clear, colourless, liquid D NaOH: water like viscosity, odourless, colourless, clear Prepared ASA sample: white, solid, grainy Mixture of NaOH and prepared ASA sample: clear, colourless, liquid FeCl 3 : liquid, yellow, clear, odourless Mixture of NaOH + ASA + FeCl 3 : dark brown, liquid, opaque, odourless E Curvette A: dark purple/brown liquid Curvette B: dark purple/brown liquid Curvette C: dark reddish brown liquid Curvette D: light brown liquid Curvette E: yellow liquid Prepared ASA sample: dark brown liquid Table 2: Quantitative Data Collected From Part A-C Mass of salicylic acid (g) 0.18 Volume of acetic anhydride (mL) 0.34 Mass of filter paper (g) 0.62 Mass of “impure” ASA + filter paper (g) 0.80 Mass of prepared “impure” ASA (g) 0.12 Melting Point range of prepared ASA ( ℃ ) 102.3 ℃ - 105.7 ℃ Melting Point range of standard ASA ( ℃ ) 138.9 ℃ - 143.5 ℃ Table 3: Results from Part D-E

3 Sample Absorbance Reading Standard A 1.30 Standard B 1.02 Standard C 0.80 Standard D 0.55 Standard E 0.25 Prepared ASA 0.88 Questions 1. Construct a beer’s law plot of Absorbance versus Concentration and add a computer generated line of best fit. Show the slope intercept form of the best fit line. 2. a) Determine the concentration of your prepared iron (III) Salicylate Dianion solution (pure ASA) in the 10.0 mL of 1.0 M in mg/mL (part D) using the Beer’s law plot completed in Question 1. y = 7.2873x + 0.0115 0.88 = 7.2873x + 0.0115 0.88 - 0.0115 = 7.2873x x = 0.8685 7.2873 x = 0.119 mg/mL b) Then, calculate the mass (in mg) of pure ASA knowing that the two consecutive dilutions were done to prepare the solution. Show all of your work. C 3 x V 3 = C 2 x V 2

4 = C 2 𝐶3 ? 𝑉3 𝑉2 C 2 = (0.119 ??/?𝐿)(25?𝐿) (5?𝐿) C 2 = 0.595 mg/mL C 1 x V 1 = C 2 x V 2 C 1 = 𝐶2 ? 𝑉2 𝑉1 C 1 = (0.595 ??/?𝐿)(100?𝐿) (5?𝐿) C 1 = 11.9 mg/mL m = CV m = (11.9 mg/mL)(10mL) m = 119 mg of pure ASA 3. A standard “Bayer Aspirin'' tablet contains 325 mg of acetylsalicylic acid by weight. If the absorbance of this commercial tablet was measured to be 2.57, is the claim made by the drug company accurate? Explain your answer and show your work. y = 7.2873x + 0.0115 (2.57) = 7.2873x + 0.0115 2.57 - 0.0115 = 7.2873x x = 2.5585 7.2873 x = 0.351 mg/mL C 3 x V 3 = C 2 x V 2 = C 2 𝐶3 ? 𝑉3 𝑉2 C 2 = (0.351 ??/?𝐿) (25?𝐿) (5?𝐿) C 2 = 1.755 mg/mL

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version