Qualitative Comparative Analysis of Sustainable and Traditional Methods for

the Synthesis of Acetylsalicylic Acid (Aspirin)

Jessica Barilone 1, 2

1 Department of Chemistry2 Department of Environmental Science and Policy

University of Southern MaineSpring 2011

Goals of Research

● Utilize green chemistry principles to develop a green method for the synthesis of aspirin

● Compare the purity of aspirin produced from traditional and sustainable methods using state-of-the-art instrumentation

● Compare the % yield of aspirin in traditional vs sustainable methods

Major Goals of Green Chemistry

●Green Chemistry: Source Reduction/Prevention of Chemical Hazards- Design chemical products to be less hazardous to human health and the environment

- Use feedstocks and reagents that are less hazardous to human health and the environment - Design syntheses and other processes to be less energy and materials intensive

(high atom economy, low E-factor) -Use feedstocks derived from annually renewable resources or from abundant waste -Design chemical products for increased, more facile reuse or recycling

●Reuse or Recycle Chemicals

●Treat Chemicals to Render Them Less Hazardous

●Dispose of Chemicals Properly

Source: US EPA

Applying the Principles of Green Chemistry

●Use reagents that are lesshazardous to human health and the environment

●Design syntheses to be less energy and material intensive

Eliminated the use ofcatalyst

Eliminated the use of additional solvents

Used a lower energyheat source

Synthesis Reaction

A catalyst, such as sulfuric or phosphoric acid, is generally used to speed up the reaction

Mechanism of Formation

Methodology

TraditionalHeat Source: Hot water bathCatalyst: Phosphoric AcidCooling Source: Ice bath

Additional Solvents:Ethanol

SustainableHeat Source: 1480 watt conventional microwaveCatalyst: NoneCooling Source: Freezer

Percent Yield of Aspirin

Table 1. Percent Yield of Pure Aspirin for Traditional and Sustainable Methods.

Method Traditional Sustainable

# of Trials 4 8

Average % Yield 61.2 57.92

Standard Deviation

± 8.3 ± 6.4

IR Results

Anomaly in Sustainable IR

Melting Point and TLC Results

Sample Average Melting Point (ºC) Rf valuePure Aspirin 133* 136* 0.8

1 T 134 136 0.7

2 T 136 138 0.8

3T 133 136 0.8

4T 137 139 0.8

3S 127 129 0.8

4S 124 129 0.8

5S 134.5 138 0.8

6S 133 136 0.8

7S 128.5 132 0.8

8S 128 137 0.8

9S 134 136 0.8

10S 134 136 0.8

*Values based on literature

Is it More Sustainable?

Traditional● Requires strong acid for

catalysis● Requires solvents for

purification● Requires a hot plate (less E

efficient than microwave, Mitra et. al.)

● Requires water for hot water and ice bath

Sustainable● NO catalyst required● NO solvents for

purification● Uses minimal microwave

radiation● NO additional water for

baths

Conclusions

● Method is more sustainable than traditional methods for aspirin synthesis

● Method would be useful for academic laboratory procedures● Increase # of replicates ● Reduce materials needed● Potentially lower costs for a department

● Method would require changes for mass production

Sources

Mitra et. al. Green Chemistry in Teaching Laboratory: Microwave Induced Reactions. Available at:HTTP://web.njit.edu/~mitra/green_chemistry/Contact.htm

United States Environmental Protection Agency (US EPA). (2011). Green Chemistry. Available at: HTTP://www.epa.gov/greenchemistry/

Acetylsalicylic Acid (Aspirin)

Aspirin works as a suicide inhibitor.