INORGANIC AND ORGANIC CHEMISTRY LABORATORY REPORT

Subject : Inorganic and Organic Chemistry LaboratoryLecturer : Mr. Hery Susanto M.SiInstructor : Mr. Tabligh Permana, Mr.Hery Sutanto M.SiFaculty/Class : Life Science/LS 2ADate of Experiment : 11 March 2014Date of Lab. Report : 25 March 2014Semester : 2Time of Experiment : 14.00 – 17.00 p.m

Experiment: Preparation of Aspirin

Name: Kristania HadhiwaluyoChita Sakina PutriantiElias Harmanto

S W I S S G E R M A N U N I V E R S I T Y

I. Objectives

To understand the methods used for the synthesis of aspirin in laboratory.

II. Theoretical Background

Aspirin

Aspirin is a medicine that relieves pain and reduces fever. It is used to relieve many kinds of minor

aches and pains—headaches, toothaches, muscle pain, menstrual cramps, the joint pain from arthri-

tis, and aches associated with colds and flu. Some people take aspirin daily to reduce the risk of

stroke, heart attack, or other heart problems.

Aspirin-also known as acetylsalicylic acid-is a synthetic organic derived from salicylic acid. Sali-

cylic acid is a natural product found in the bark of the willow tree and was used by the ancient

Greeks and Native Americans. Aspirin belongs to a group of drugs called salicylates. Other members

of this group include sodium salicylate, choline salicylate, and magnesium salicylate. These drugs

are more expensive and no more effective than aspirin. However, they are a little easier on the stom-

ach. Aspirin is quickly absorbed into the bloodstream and provides quick and relatively long-lasting

pain relief. Aspirin also reduces inflammation. Researchers believe these effects come about because

aspirin blocks the production of pain-producing chemicals called prostaglandins.

In addition to relieving pain and reducing inflammation, aspirin also lowers fever by acting on the

part of the brain that regulates temperature. The brain then signals the blood vessels to widen, which

allows heat to leave the body more quickly.

To synthesize aspirin, a common analgesic drug, there are three parts of experiment that involved:

the preparation of aspirin, the recrystallization of aspirin, and the estimation of the purity of the final

product.

Aspirin can be made by reacting salicylic acid with acetic acid in the presence of an acid catalyst;

can be phosphoric acid, H3PO4, or sulfuric acid, H2SO4. The phenol group on the salicylic acid forms

an ester with the carboxyl group on the acetic acid.

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Esterification of Aspirin Using Acetic Anhydride

Recrystallization

Primarily recrystallization is a process of purifying compound in the laboratory by forming precipi-

tate. In this experiment, recrystallization process is used to recrystallize the target product in order to

be separated from its impurities. It seen in the figure below that salicylic acid is the limiting reactant

and the acetic anhydride is excess. After the reaction (heating period) is over, the excess unreacted

acetic anhydride will be destroyed by the addition of water to the mixture: water reacts with acetic

anhydride to form 2 molecules of acetic acid.

Decomposition of Unreacted Acetic Anhydride

When the esterification reaction is complete, cold water will be added to the mixture to allow recrys-

tallization process to happen, as the additions of water cause the precipitation of the acetylsalicylic

acid and will react with any remaining acetic anhydride..

Vacuum Filtration

Vacuum filtration is a technique for separating a solid product from a solvent or liquid reaction mix-

ture. The mixture of solid and liquid is poured through a filter paper in a Buchner funnel. The filter

traps the solid and the liquid is drawn through the funnel into the flask below, by a vacuum. In this

experiment, the solid aspirin will be collected using vacuum filtration. Any other reaction ingredients

that are soluble (this includes acetic acid, phosphoric acid, and water) will pass through the filter pa-

per.

Finally, the collected aspirin will be tested for its purity using FeCl3 (aq). Iron (III) ion reacts with

phenols to form a purple complex. Salicylic acid contains a phenol group, but acetylsalicylic acid

does not. Therefore, the addition of FeCl3 to an aspirin sample and the purple color changed means

that there is still some salicylic acid present and the sample is impure. If aspirin is obtained, the as-

pirin then will be again purified by recrystallization. In this purification method, the crude aspirin

will be dissolved in a small amount of warm ethanol. Water will then be added and the solution will

be cooled slowly and then chilled. The acetylsalicylic acid will recrystallize, and the solid impurities

(unreacted salicylic acid) should remain dissolved in the solution. The solid aspirin will again be col-

lected using vacuum filtration and tested for purity. This aspirin should be more pure than the origi-

nal aspirin.

III. Equipment and Materials

Equipment:

- Petri dish

- Volumetric flask, 100 cm3

- Volumetric flask, 25 cm3

- Volumetric pipette, 3, 5 cm3

- Graduated pipette, 25 cm3

- Erlenmeyer flask, 100 cm3

- Bulb, 4

- Round bottom flask, 2

- Beaker glass, 3, 1000 cm3

- Beaker glass, 4, 50 cm3

- Reflux pipe (condenser), 2

- Burette Clamp, 2

- Water cooler (thermostat)

- Plastic water hose, 3

- Hot plate, 2

- Spatula

- Digital Balance

- Vacuum filtration unit

- Filter paper, 2

- Test tube, 1

- Magnetic stirrer, 2

Materials:

- Vaseline wax

- FeCl3(l), Iron(III) Chloride

- C7H6O3(s), Salicylic Acid, 2 g

- H2O(l), distilled water, 750 cm3

- H2O(l), cold distilled water, 100 cm3

- C4H6O3(l), Acetic anhydride, 3.0 cm3

- H2SO4(l), concentrated sulfuric acid, 1 cm3

- C2H5OH(l), ethanol (96%), 20 cm3

IV. Procedures

1. Step 1: Preparation of Equipment and Materials

1. Using a bulb and a graduated pipette in the lab hood, 20 cm3 of C2H5OH(l), ethanol

(96%) was placed into the 25 cm3 volumetric flask.

2. The volumetric flask was labeled with “flask 1” label.

3. 100 cm3 distilled water, H2O(l),, was poured into the other volumetric flask with the

size of 100 cm3

4. The volumetric flask was labeled with “flask 2” label.

5. Both “flask 1” and “flask 2” were placed inside the refrigerator in order to cool

them.

6. Both beaker glass with the size of 1000 cm3 was half filled with distilled water,

H2O(l),, and each of them was placed on top of a hotplate .

7. One magnetic stirrer was placed inside each of the beaker glass.

8. The beaker glasses in step 6 were heated until boiling up to a temperature of 350 0C.

9. While waiting for the water to boil, the experimental setup was set according to

the figure shown below

10. The thermostat connected to the two water hose was set to the temperature of 5 0C.

11. 1 g of C7H6O3(s), Salicylic Acid was placed on top of a petri dish using a spatula to

be measured on the digital balance and was placed into the round bottom flask

which was labeled with “flask 1”.

12. The previous step was repeated but the substance was placed on the other round

bottom flask which was labeled with “flask 2”.

13. 1.5 cm3 C4H6O3(l), Acetic anhydride was taken by using , 5 cm3 volumetric pipette

and placed into the round bottom flask which was labeled with “flask 1”.

14. The previous step was repeated but the substance was placed on the other round

bottom flask which was labeled with “flask 2”.

15. 600 cm3 H2O(l), distilled water was inserted into each round bottom flask.

16. Lastly, 0.5 cm3 concentrated sulfuric acid, H2SO4(l), was taken using 5 cm3

volumetric pipette and placed into the round bottom flask which was labeled with

“flask 1”.

17. The previous step was repeated but the substance was placed on the other round

bottom flask which was labeled with “flask 2”.

18. After the water in each 1000 cm3 beaker that were placed on top of the hot plate

were boiling, the magnetic stirrer present inside the water was removed and then

the surrounding surface of the end of the reflux/condenser pipe and on the mouth

of the round bottom flask were rubbed by Vaseline wax.

19. Slowly each round bottom flask was placed on the end of the reflux/condenser

pipe until its surfaces that was previously rubbed by Vaseline wax stick together

but it was ensured that half of its bottom surface was inside the boiling water. As

shown on the figure below

20. For about 20 to 30 minutes, the mixture was heated under reflux while steadily

stirred by shaking both of the round bottom flasks.

2. Step 2: Recrystallization procedure

1. Each of the solution that was present in each flask was left to cool in room

temperature.

2. After the temperature of the solution cooled, it was poured into two separate glass

beaker with the size of 50 cm3, each labeled with “beaker 1” and “beaker 2”

3. 50 cm3 of the 100 cm3 H2O(l), cold distilled water, that was placed previously inside

the refrigerator was poured into “beaker 1” while the solution that was present

inside being mixed together.

4. The previous step was repeated by using the other flask (“beaker 2”) and also the

leftover 50 cm3 H2O(l), cold distilled water.

5. The solutions that were present inside each glass beaker were stirred constantly

until white precipitation appears making the solution cloudy, full of white flakes.

3. Step 3: Vacuum Filtration

1. The vacuum filtration setup was set according to the figure shown below

2. A filter paper was used to collect the crystals from the recrystallization process,

the filter paper was folded twice and half of the side of the filter paper was ripped

to decrease the edge that was formed when filter paper was inserted to the funnel.

3. Filter paper was inserted into the funnel that was placed on top of the large

Erlenmeyer flask.

4. H2O(l), distilled water was sprayed on the inner side of the filter paper to make it

stick on the funnel inner surrounding

5. The solution from the beaker glass, “beaker 1”, was pour a little by little into the

funnel passing the wet filter paper into the larger Erlenmeyer flask right below the

funnel

6. The solution was added slowly to ensure that no solution spilled into the outside

surface of the filter paper

7. Once all solution was filtered, the wet filter paper was removed from the filter

setup and the remaining solution in the larger Erlenmeyer flask was discarded

8. The crystals that were filtered and present on the filter paper was placed on a

small beaker glass, labeled “beaker 1a”

9. The previous steps (2nd up to the 8th step) were repeated for the other beaker glass,

“beaker 2” and placed in another new glass beaker, labeled “beaker 2a”

4. Step 4: Proving the Obtained Aspirin

1. The precipitation that was collected in both “beaker 1a” and “beaker 2a” was

washed with 5 cm3 H2O(l), cold distilled water

2. The previous step was repeated but this time each solution in both “beaker 1a” and

“beaker 2a” was washed with 10 cm3 of the 20 cm3 the C2H5OH(l), ethanol (96%)

that was previously placed in the refrigerator (another volumetric pipette with size

of 5 cm3 was used to obtain the substance from the volumetric flask).

3. The crystals that were obtained from both recrystallization and vacuum filtration

were placed and combined into one test tube

4. Few drops of FeCl3(l), Iron(III) Chloride that was taken using a dropping pipette

was added into the test tube containing the crystals.

5. The change of the color was observed to test the purity of the obtained Aspirin.

V. Observation (Data)

Changes Observed

During the reaction(When the substances are placed inside the round bottom flask were heated under reflux)

When the substances were heated under reflux for

about 20 to 30 minutes, the substance at the bottom

side of the round bottom flask changed color into dark

brown indicating changes that is formed due to the

chemical reaction.

Recrystallization Process

Precipitation is found in one of the beaker but after it

is filtered it is found out that no crystals or containing

Aspirin and its other side product (i.e. Salicylic acid)

is filtered and present in the filter paper. So the 4th step

was not conducted in this experiment since there is no

Aspirin and its other side product (i.e. Salicylic acid)

is produced.

Vacuum Filtration Process

VI. Discussion

According to the observation shown in the data table above, it is concluded that there is no Aspirin and its

other side product (i.e. Salicylic acid) that is produced from this experiment. It is because even though

precipitation is found during the recrystallization process it does not necessary mean that it is the actual

product that supposed to be obtained from this experiment. Some factors that contribute to the fail of this

experiment can be observed from the steps of the procedure, which are; preparation of the substance,

equipment, and materials needed, recrystallization, and vacuum filtration. During the first step of the

experiment, all the substances present inside each round bottom flask; 1 g C7H6O3(s), Salicylic Acid, 1.5 g

C4H6O3(l), Acetic anhydride, and 0.5 cm3 H2SO4(l), concentrated sulfuric acid that act as a catalyst, is heated in

600 cm3 boiling water. The present of high temperature as a result from the boiling water in the surrounding

of the round bottom flask and concentrated sulfuric acid, H2SO4(l) that act as catalyst that speed up the

reaction along with becoming an intermediate in the complex series of reaction that happen during the

synthesis, allow the reaction of this experiment to be completed forming Aspirin, shown in the figure below.

However in the case of this experiment, the reaction that happen does not proceed in a way that it supposed

to be or in other words the reaction is incomplete. It is due to the fact that the reactants, present in each

round bottom flask, are unable to mix and react together when it is heated under reflux even when they are

placed in a favorable environment condition, as the round bottom flasks that were attached to the

reflux/condenser were not steadily stirred by shaking both of the round bottom flasks. The stirring of the

mixture present inside both round bottom flasks is a crucial step in this experiment because it is the way for

the reactants to be able to mix together and react properly because by stirring the mixture it causes collision

between the particle of the reactants, that allow them to perform chemical reactions which involve breaking

and making bonds as stated by the collision theory. As a result even when all the necessary condition for this

experiment is followed, the reaction cannot occur properly and form the product of the reaction. In addition,

during this process there are too much catalyst, sulfuric acid, H2SO4(aq) that is used inside this experiment,

as a result the sulfuric acid, H2SO4(aq), that was supposed to act as the catalyst which increase the speed of the

reaction disturb the reaction by reacting (undergoing chemical change) thereby causing the reaction to be

incomplete. The very high temperature of the hot plate used to heat the solution also become the other factor

that contribute to the downfall of this experiment. It is because the high temperature that is way too high

cause the Vaseline wax that is rub around the end of the reflux/condenser pipe and on the mouth of

the round bottom flask to melt and react with the mixture inside the flaks thereby disturbing the reaction

which eventually cause the reaction to be incomplete.

The downfall of this experiment can be proven further in the next step of this experiment, which is

recrystallization and vacuum filtration. In the recrystallization process, the solution containing all the

reactants were cooled in room temperature with the help of the cold distilled water H2O(l) that was added

afterwards. When cold distilled water, H2O(l) was added while steadily stirring the solution, it was seen that

there is a white precipitation that appears which make the solution cloudy and full of white flakes.

Additionally, the cold distilled water, H2O(l) that was added also serve as a substance that help to remove the

excess, unreacted C4H6O3(l), Acetic anhydride in this experiment by hydrolyzing it into Acetic acid,

CH3COOH when it reacts with the water. Hot distilled water, H2O(l) is not used instead of cold one because

hot water will not allow the solution to undergoes recrystallization. Furthermore, the addition of hot distilled

water, H2O(l) will not remove the excess, unreacted C4H6O3(l), Acetic anhydride in this experiment, instead it

will dissolve the Acetic anhydride, C4H6O3(l) due to the high temperature that it has. However, in the end of

the process it is found that there is also a possibility that the main substances used as the reactants in this

investigation is not a pure substances. Because the crystallized precipitation that formed during

recrystallization process was proven for not containing aspirin that we want and it is actually still containing

more impure sample than the aspirin or even without containing the aspirin.

This is proven when the vacuum filtration process that when the crystals, formed during recrystallization,

is filtered through the filtration unit no crystal-like structure are found from both solution in both

round bottom flasks that is trapped in the filter paper. During the process it is found that all the

substances inside the solution like water (H2O(l)), concentrated sulfuric acid (H2SO4(l)), acetic anhydride

(C4H6O3(l),) that is hydrolyzed into Acetic acid (CH3COOH), including the white precipitate which has a

possibility being the Salicylic acid (C7H6O3(s)) or the Aspirin (C9H8O4(s)) were filtered down, passing through

the filter paper unfiltered into the large Erlenmeyer flask beneath. Therefore the vacuum filtration unit that

was used in order to remove the impurities or other side products of the experiment (other substances beside

Salicylic acid (C7H6O3(s)) or the Aspirin (C9H8O4(s)) did not work as it is supposed to as no Salicylic acid

(C7H6O3(s)) or the Aspirin (C9H8O4(s)) is found to be present on the filter paper.

The fall of this experiment finally forbid the conduct of the last step of this experiment which is proving the

obtained Aspirin. If Salicylic acid (C7H6O3(s)) or the Aspirin (C9H8O4(s)) is found to be present on the filter

paper indicating a possibility of the success of the experiment, this last stage can be used to prove whether

the Aspirin that is obtained is pure or not. Basically there are several steps that is used, firstly the crystals

that were supposed to be produced are wash with 5 cm3 H2O(l), cold distilled water and 10 cm3 of the 20 cm3

the C2H5OH(l), ethanol (96%) that was previously placed in the refrigerator. Cold water is used to wash the

obtained crystals instead of hot distilled water to prevent the dissolution of the crystal that led to the need of

repeating the vacuum filtration once more. Whereas the 10 cm3 of the 20 cm3 the C2H5OH(l), ethanol (96%)

was added in order to remove the unneeded Salicylic acid (C7H6O3(s)) as it is able to interact with the

hydroxyl (-OH) group of the Salicylic acid, enabling it to be removed from the crystal when washed away

with the ethanol solution. Finally the addition of few drops of FeCl3(l), Iron(III) Chloride into the solution

allow us to check the purity of the Aspirin (C9H8O4(s)) produced by looking at the color change that is

produced when FeCl3(l), Iron(III) Chloride is added into the solution. It is because when phenol (benzene

group that has a hydroxyl group attached to it) group of the excess Salicylic acid (C7H6O3(s)) react with

FeCl3(l), Iron(III) Chloride, it turn the color of the solution into purple, and the more purple it becomes it

indicates more Salicylic acid (C7H6O3(s)) that is not yet removed from the solution or in other words higher

impurity of the Aspirin (C9H8O4(s)) produced.

VII. Conclusion

Aspirin is medicine from a synthetic organic derived from salicylic acid that could relieve many kinds of

minor aches and pains. We synthesized aspirin through preparation of aspirin, recrystallization & vacuum

filtration and finally the test of the purity of the aspirin produced. However, we did not do the third step of

the experiment due to no existence of aspirin-crystal during filtration process. The several factors that may

affect the end result of this investigation is primarily misconducting the procedure and the uncontrolled

condition when conducting the reaction. As a result the reaction of C7H6O3(s), Salicylic Acid and C4H6O3(l),

Acetic anhydride when they are heated under reflux become incomplete and did not produce the end product,

which is the Aspirin (C9H8O4(s)). Other factors such as unstirred mixture, the too many catalyst, sulfuric acid,

H2SO4(aq) that is actually used for increasing the rate of the reaction, impurity of the substances used as

reactants, and finally the very high temperature that caused Vaseline wax to melt and react when it comes

into contact with the heated mixture also contribute to the downfall of the experiment. In the other hand, if

we succeed to filtrate the crystals and obtained the Aspirin (C9H8O4(s)), we need to add a few drops of FeCl3(l),

Iron(III) Chloride, to test its purity as there is a possibility that its side product which is Salicylic Acid.

(C7H6O3(s),) may also present among the filtrate crystals. Finally the color change indicates the purities of

aspirin produced if it turns to dark purple it means that it contains a great amount of salicylic acid and if it

turns to light purple it means it contains a small amount of salicylic acid. So, the lighter purple color we get,

the purer aspirin we have.

VIII. References

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<http://www.chem.latech.edu/~deddy/chem104/104Aspirin.htm>.

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"aspirin playV2('en/US/d3/d3djsfshd7ssdnsfhn');playV2('en/UK/d3/d3djsfshd7ssdnsfhn')." TheFreeDic-

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