1. Kolbe-Schmitt Salicylic Acid Synthesis and Utilization
Kevin McGovney
Aurion Farhadi
Nicholas Bean

2. Purpose: Synthesize Salicylic Acid Using the Kolbe-Schmitt Reaction
Kolbe-Schmitt Reaction: Was first successfully carried out in 1860 by a German chemist named Hermann Kolbe, by heating a mixture of phenol and sodium hydroxide in the presence of carbon dioxide at high pressure.
The product: Salicylic Acid!! A chemical which has proved to be immensely versatile and valuable. It is even listed in the WHO List of Essential Medicines.
1) History of Salicylic Acid (Accessed March 2017)

3. Many uses of Salicylic Acid
Used in treatment products for acne, dandruff, and psoriasis
Used for removal of warts and calluses
Market for salicylic acid expected to reach $550 million by 2024
Precursor to Aspirin
2) Salicylic Acid Market Size To Reach $547.5 Million By Grand View Research (Accessed March 2017)

4. Identity, Structure, and Synthesis
IUPAC name 2-hydroxybenzoic acid
Structure consists of a phenol group with
an ortho-directed carboxylic acid group
3) WHO Model List of Essential Medicines. Who Medicines

5. 4) J. Luo, S. Preciado, P. Xie, I. Larrosa, Carboxylation of Phenols with CO2 at Atmospheric Pressure, Chem. Eur. J. 2016, 22, DOI: /chem

6. IR and H-NMR of Salicylic Acid

7. Aspirin Synthesis from Salicylic Acid

8. IR and H-NMR of Aspirin

9. Differences in Spectra
Salicylic acid has alcohol and carboxylic acid groups, while aspirin has carboxylic acid and ester groups.
The alcohol groups typically show stretches between 3200 and 3600 ppm, while carboxylic acids will produce bends between 2500 and 3000 ppm.
For acetylsalicylic acid (Aspirin), we no longer see the strong stretch from the alcohol group, but we still see the presence of carboxylic acid.
New signal around 1750 ppm for ester in Aspirin 5)

10. Merits and Deficiencies of High-Pressure Synthesis
Synthesis of Salicylic Acid can be done using cheap, common reagents
Does not provide noteworthy contribution to the reduction of atmospheric carbon dioxide
Strong economic incentive for capture and distribution of carbon dioxide as a reagent
Requires a facility that can carry out the synthesis under high-pressure

11. Merits and Deficiencies of Low Pressure Synthesis
Takes place under standard atmospheric pressure with the addition of a 2,4,6-trimethylphenyl
This allows salicylic acid to be synthesized without expensive lab equipment
Different and less common precursors are required using this method.
Variation in substitution of the phenol group results in differences in percent yield.

12. Summary
Kolbe-Schmitt reaction is a long standing central process to the synthesis of salicylic acid
Salicylic acid is a substance with many versatile industrial applications
The utilization of carbon dioxide in the Kolbe-Schmitt reaction provides economic incentive for its capture and distribution