Characterization of Aspirin

b. Characterization of Aspirin

B. Set – up

Fig. 11.1. Suction Filtration Set – up

C. Table 11.1 List of Necessary Chemicals

Sample
Structure
Purpose
Physical Properties
Hazards
Salicylic Acid

Starting Material

Appearance: white powder
Molar Mass: 138.12 g/mol
Melting Point: 1590C
Boiling Point: 2110C
Density: 1.44 g/cm3
Mildly irritating (pulmonary irritants). Harmful by inhalation, ingestion and through skin absorption.
Acetic Anhydride

Starting, Material, serves also as the solvent colorless liquid with a smell of acetic acid
Molar Mass: 102.09 g/mol
Melting Point: -73.1 0C
Boiling Point: 139.8 0C
Density: 1.082g/cm3

Corrosive Flammable and Lachrymator which makes eyes teary. It is poisonous and will cause serious damage if swallowed or inhaled.

Phosphoric Acid

Catalyst colorless liquid,
Molar Mass: 98.00 g/mol
Melting Point: - 42.35 °C (anhydrous)
29.32 (hemihydrate)
Boiling Point: 158 0C
Density: 1.685g/cm3
Corrosive, Toxic
Water

Used to destroy acetic anhydride which did not react; precipitates crude aspirin colorless liquid
Molar Mass: 18.06 g/mol
Melting Point: 0 °C
Boiling Point: 100 0C
Density: 1.0g/cm3
--------------
Diethyl ether

Recrystallization solvent colorless liquid with a sweet, characteristic smell
Molar Mass: 74.12 g/mol
Melting Point: - 116°C
Boiling Point: 35 0C
Density: 0.7134 g/cm3
Easily ignited, Harmful by ingestion, inhalation or through skin contact.
Petroleum Ether

Salt out aspirin from the solvent

Colorless liquid Molar Mass -
Melting Point-40 ̊C
Boiling Point 36-70 ̊C
Density - 0.6475 g/ml
The liquid is volatile and very flammable. It presents a high fire risk.
Some formulations may contain chemicals that are suspected carcinogens. Avoid ingestion and inhalation.
Acetylsalicylic Acid

Product

White crystalline powders Molar Mass180.16 g/mol
Melting Point 135 ̊C
Boiling Point 140 ̊C
Density
1.35 g/ml
Harmful if swallowed in quantity. Skin, eye and respiratory irritant. May act as an allergen in susceptible people.

IV. Data and Results

Table 11.2. Physical Examination of Samples
Sample
Observations
Salicylic Acid

Acetic Anhydride

85% Phosphoric Acid

Petroleum Ether

Diethyl Ether

Iodine Solution

Table 11.3. Observation on the preparation of aspirin
Actions / Reagents Added.
Observations
Salicylic Acid

Addition of Acetic Anhydride

Addition of 85% Phosphoric Acid

Heating under steam bath

Addition of cold, distilled water

Cooling (Ice bath)

Suction Filtration

Filtrate

Residue

Air – dried crystals

What is the balanced chemical equation for synthesis of aspirin?

Table 11.4. Percentage yield of actual yield of Aspirin
Substance/Reagent/Apparatus
Weight (g)
Filter paper + Watch glass

Filter paper + Watch glass + Crude aspirin

Crude Aspirin

Theoretical Yield

Percentage yield (%): _______

Table 11.5. Observations on the recrystallization of aspirin
Actions / Reagents Added.
Observations
Crude Aspirin

Addition of diethyl ether

Addition of Pet Ether

Cooling

Filtration

Filtrate

Residue

Dried Crystals

Table 11.6. Percentage Yield
Substance/Reagent/Apparatus
Weight (g)
Filter paper + Watch glass

Filter paper + Watch glass + Crude aspirin

recrystallized Aspirin

Theoretical Yield

Percentage yield

Table. 11.7. Melting Point Determination of Crude and Purified Aspirin
Addition/ Reagent added
Observation
Crude aspirin

Temp. at which crude aspirin began to melt (0C)

Temp. at which crude aspirin finished to melt (0C)

Melting Point range of crude aspirin (0C)

Purified Aspirin

Temp. at which purified aspirin began to melt (0C)

Temp. at which purified aspirin finished to melt (0C)

Melting Point range of purified aspirin (0C)

Literature value of melting point range of Apparatus (0C)

Table 11.8. Differentiation of aspirin from starting material
Sample
Sol’y in H2O
FeCl3 test
Acidic KMnO4 test

Observation
(+/-)
Observation
(+/-)
Observation
(+/-)
Salicylic Acid

Acetic Anhydride

Acetylsalicylic Acid

Table 11.9. Differentiation of synthesized aspirin and commercially available aspirin
Sample
Reaction with iodine solution
Synthesized Aspirin

Commercially Available Aspirin

V. Sample Calculations
1.) Theoretical Yield =
2.0 g salicylic acid ())= 2.61 g
2.) Actual Yield = weight of desired product
3.) Percentage Yield = x 100

VI. References

Groggins, P.H. Unit Processes in Organic Synthesis. 1952. Mc-Graw Hill, Inc.:USA.

Eaton, D.C. Laboratory Investigations in Organic Chemistry. 1989. Mc-Graw Hill, Inc.:USA.

Timberlake, K. General, Organic, & Biological Chemistry; Structures of life. Platinum Ed.(2004). Pearson Education Inc. 234-238.

Matta, M.S., Staley, D. D., Waterman, E. L. et. al., 2003. Pearson Education (Asia) Pte Ltd.: Singapore

Synthesis of Apirin. (n.d.). Retrieved September 12, 2012, from http://www.xula.edu/chemistry/department/organic/Notes/24Aspirin.pdf/

Chemistry Experiment: Synthesis of Aspirin. (2003). Retrieved September 12, 2012, from http://www.earlham.edu/~chem/chem111f03/labs/Experiment%2011.pdf/

The Synthesis of Apirin. (n.d.). Retrieved September 12, 2012, from http://www.reachoutmichigan.org/funexperiments/quick/csustan/aspirin.htm/

Excess and limiting Reagents. (n.d.). Retrieved September 14, 2012, from http://www.science.uwaterloo.ca/~cchieh/cact/c120/limitn.html

References: Groggins, P.H. Unit Processes in Organic Synthesis. 1952. Mc-Graw Hill, Inc.:USA. Eaton, D.C. Laboratory Investigations in Organic Chemistry. 1989. Mc-Graw Hill, Inc.:USA. Timberlake, K. General, Organic, & Biological Chemistry; Structures of life. Platinum Ed.(2004). Pearson Education Inc. 234-238. Matta, M.S., Staley, D. D., Waterman, E. L. et. al., 2003. Pearson Education (Asia) Pte Ltd.: Singapore Synthesis of Apirin. (n.d.). Retrieved September 12, 2012, from http://www.xula.edu/chemistry/department/organic/Notes/24Aspirin.pdf/ Chemistry Experiment: Synthesis of Aspirin. (2003). Retrieved September 12, 2012, from http://www.earlham.edu/~chem/chem111f03/labs/Experiment%2011.pdf/ The Synthesis of Apirin. (n.d.). Retrieved September 12, 2012, from http://www.reachoutmichigan.org/funexperiments/quick/csustan/aspirin.htm/ Excess and limiting Reagents. (n.d.). Retrieved September 14, 2012, from http://www.science.uwaterloo.ca/~cchieh/cact/c120/limitn.html