WM5 The synthesis of salicylic acid and aspirin - PowerPoint PPT Presentation

1 / 6
About This Presentation
Title:

WM5 The synthesis of salicylic acid and aspirin

Description:

WM5 The synthesis of salicylic acid and aspirin. Synthesis is better than harvesting ... Aspirin is not very soluble in water so it became the first medicine to ... – PowerPoint PPT presentation

Number of Views:200
Avg rating:3.0/5.0
Slides: 7
Provided by: ourladysco
Category:

less

Transcript and Presenter's Notes

Title: WM5 The synthesis of salicylic acid and aspirin


1
WM5 The synthesis of salicylic acid and aspirin
2
Synthesis is better than harvesting
  • Chemists can synthesise (artificially produce)
    compunds, once the structure is known.
  • Phenols germicidal properties were well known by
    the end of 19th Century.
  • Phenol (a product from heating coal) was readily
    available.
  • 2-hydroxybenzoic acid has 1 extra functional
    group, compared to phenol.

3
How is phenol converted into 2-hydroxybenzoic
acid?
  • Draw the structures of phenol and
    2-hydroxybenzoic acid.
  • What extra atoms need to be added to phenol?
  • What conditions and reagents are needed?
    (research this).

4
Kolbe Schmitt synthesis
  • Kolbe (1874) produced salicylic acid from dry
    sodium phenoxide in a stream of carbon dioxide at
    150 160 C. He found that the yield was only
    50.
  • Schmitt (1884) increased the yield to 90 by
    increasing the pressure to 5 bar (7atm), until no
    more CO2 was taken up.

5
On an industrial scale
  • Felix Hoffmann developed process for the Bayer
    company.
  • Unpleasant side-effects on mouth, gullet and
    stomach.
  • Hoffmann modified the structure and tested
    products on his rheumatic father!
  • 1898 2-ethanoylhydroxybenzoic acid (aka
    acetylsalicylic acid OR aspirin) produced

6
Aspirin made by esterification
  • Aspirin is an ester O
  • Functional group R-C-O-R
  • Alcohol acid ? ester
  • Aspirin is not very soluble in water so it became
    the first medicine to be sold as tablets.
Write a Comment
User Comments (0)
About PowerShow.com