Faculty of Engineering
Cairo University
Chemical Engineering Department-Second Year
Aspirin
Submitted To:
Dr. Ehab Abadir
Submitted By:
Ahmed Mohamed Abouldahab
Ahmed Mohamed Gamal
Abdalla Adel AbdelAziz
Mohamed Kamel Ragai
Mostafa Hussein El-Nahass
Section 1
Section 1
Section 2
Section 3
Section 4
Contents
Introduction ........................................................................................................ 3
History ................................................................................................................ 3
Preparation ......................................................................................................... 4
Industrial flow sheet ........................................................................................... 5
Aspirin Purity test ............................................................................................... 5
Example .............................................................................................................. 6
Production of aspirin in Egypt ............................................................................. 6
Advantages and disadvantages ........................................................................... 7
References ............................................................................................................. 8
Introduction
Acetylsalicylic Acid, also known by trade name Aspirin, is an acetyl derivative of
salicylic acid that is a white, crystalline, weakly acidic substance, with melting point
137°C. It is useful in the relief of headache and muscle and joint aches. Aspirin is also
effective in reducing fever, inflammation, and swelling and thus has been used for
treatment of rheumatoid arthritis, rheumatic fever, and mild infection. Large doses
cause acid-base imbalance and respiratory disturbances and can be fatal, especially
in children. Acetaminophen (known by trade name Tylenol), which does not cause
gastric irritation but does lower fever and relieve pain, is often substituted for Aspirin.
History
For long ages the world had been suffering from not having a treatment for headache & for preventing
heart attacks which causes sudden death, that’s why scientists worked on discovering new substances
&compounds to cure that, so now a days we use aspirin, this is shown in the following paragraph.
Here is a ‘time line’ for the past 230 years to get you started..
 1830s A Scottish physician found that extracts of willow bark relieved symptoms
of acute rheumatism.
Salicin
 1870 Professor von Nencki of Basle demonstrated that Salicin was converted into
Salicylic acid in the body.
Salicylic acid
 Salicylic acid was then given to patients with fevers and their symptoms were
relieved. However, the compound caused severe irritation of the lining of the
mouth, gullet and stomach.
PHOTOCOPYP
Sodium Salicylate
 In the large doses used for treating rheumatism sodium salicylate frequently
caused the patient to vomit.
Aspirin
 1890s Felix Hofmann of the Bayer Company in Germany made aspirin which was
found to have good medicinal properties, low membrane irritation and a
reasonable taste. This followed the publication of news about the temperature
reducing properties of acetanilide which immediately spurred a chemist at
Bayer’s dye works to make some derivatives.
 He called the new medicine aspirin (‘a’ for acetyl – the systematic name for the
compound at the time was acetylsalicylic acid, ‘spir’ for spirea, the
meadowsweet plant).
 Nowadays chemists use the systematic name, ethanoyl, instead of acetyl but
the trivial name acetyl is still very common.
 1915 During World War I the British wanted aspirin but it was made by the
Germans (Bayer & Co). So the British government offered a £20,000 reward to
anyone who could develop a workable manufacturing process. This was
achieved by George Nicholas, a Melbourne pharmacist, who subsequently
gave his tablet the name ‘Aspro’.

1990s More than 10 million kilograms of aspirin are made in the US each year!
Nowadays aspirin is not only used as a painkiller but has also been proposed as
effective in reducing the incidence of heart disease.
Preparation
The synthesis of aspirin is classified as an esterification reaction. Salicylic acid is treated with acetic
anhydride, an acid derivative, causing a chemical reaction that turns salicylic acid's hydroxyl group into
an acetyl group, (R-OH → R-OCOCH3). This process yields aspirin and acetic acid, which is considered a
byproduct of this reaction. Small amounts of sulfuric acid (and occasionally phosphoric acid) are almost
always used as a catalyst. This method is commonly employed in undergraduate teaching labs.
It could also be synthesized from petroleum through this reaction
Industrial flow sheet
The starting materials are salicylic acid and acetic anhydride.
The equation for the reaction is:
(CH3CO)2O + HO.C6H4.COOH ----> CH3COO.C6H4.COOH + CH3COOH
The mixture of the two reactants is heated to about 90 °C and kept at this temperature
for several hours, after which it is allowed to cool. Crystals of aspirin separate out from
the solution and can be purified by recrystallisation.
Note that acetic anhydride reacts readily with water so all the apparatus must be dry.
Aspirin Purity test
A pure substance usually has a sharp melting point – i.e. a narrow temperature range
during which it changes from a solid to a liquid. A substance which contains impurities
often melts over a range of several degrees. Any impurities in the substance cause a
lowering and broadening of this characteristic temperature.
Substance
Melting point
salycylic acid
Aspirin
158–160 °C
138–140 ° C
Example
Acetic anhydride is added to Salicylic acid on stoichometric ratio
The reactor outputs are filtrated so that the solids Aspirin and Salicylic acid are separated together from
the liquids
Compositions of some streams are shown on the fig
Calculate the yield of the reaction .
Reactor
Filter
Process
Overall
9
10
14
9
No. of
5
independent
equations
No. of given 1
variables
No. of
1
additional
relations
5
10
5
1
2
2
0
1
1
Degrees of
Freedom
4
1
1
No. of
variables
2
 Starting from overall

Assume feed=100 moles/sec
acetic anhydride=salicylic acid=40 moles/sec
sulphuric acid=20 moles/sec
•
Output stream
aspirine=r=90% , salicylic acid =40-r=10%
r/(40-r)=9
•
r=36 moles/sec
Yeild
yeild=(36/40)*100=90%
Production of aspirin in Egypt
Bayer Healthcare in the Middle East is considered to be one of the first pharmaceutical
companies which was established in Egypt in 1960. It was decided to locate the Middle
East regional office in Cairo, Egypt in 1999 due to the strategic & the geographical
importance of Egypt in the region.
Advantages and disadvantages
Advantages
In small doses it interferes with blood
clotting
In medium doses it reduces fever and
relieves minor aches and pains
In high dosage it combats pain
Disadvantages
Kidney problem
Blood thinning effects causing internal
bleeding in the stomach
For a small number of people causes swelling and
headache
Reducing the risk of death in a person Large doses cause acid-base imbalance and
having a heart attack.
respiratory disturbances and can be fatal
References

http://aspirin.com/scripts/pages/en/home.php

http://www.drugs.com/aspirin.html

http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682878.html

http://nobelprizes.com/nobel/medicine/aspirin.htmlSDG 102 2

http://www.chemicalland21.com/lifescience/phar/ACETYLSALICYLIC%20ACID.htm

http://www.medicinenet.com/acetylsalicylic_acid/article.htm

http://chealth.canoe.ca/drug_info_details.asp?brand_name_id=1937&rot=4

http://chemistry.about.com/od/medicalhealth/ig/Drug-Photo-Gallery/Aspirin.1VJ.htm

http://www.chemistryexplained.com/A-Ar/Acetylsalicylic-Acid.htmlSDG