rekristalisasi dan aspirin.docx

I. Experiment Title : Recrystallization and Making Aspirin

II. Day / Date of Experiment : March 22nd 2013

III. Finish of Experiment : March 26th 2013

IV. Objective of Experiment :

1. Doing well recrystallization

2. Determining a suitable solvent for recrystallization

3. Eliminate impurities through recrystallization

4. Doing the manufacture of aspirin by acetylation of the phenol

5. Doing recrystallizing aspirin synthesis with good results

V. Basic Theory

Recrystallization

Recrystallization is one way of purifying solids plural is used, where such substances or

solids are dissolved in a solvent and then crystallized again. This method relies on the

solubility of a substance in a particular solvent at a time when the temperature increased.

Since the total concentration impuriti usually smaller than the concentration of the purified,

when cold, the concentration of low impuriti but the temporary solution of high concentration

products will precipitate. (Arsyad, 2001).

Recrystalitation is routinely used for the purification of compounds synthesized or

collation of result from natural ingredients, preanalized further, for example by

spectrophotometry (UV, IR, MR, and MS). (Tim Dosen Kimia Organik UNESA, 2013)

Recrystallization is an important method for the purification of organic solvent

component. There are seven methods of recrystallization are: selecting the solvent, the solute

dissolves, color removal solution, remove solids, crystallizing solution, collecting and

washing the crystals, dry products (results) (Williamson, 1999).

Salicilic acid is an acid bifungsional containing two-OH groups and-COOH. Therefore

salicylic acid may be subject to two different types of reactions the reaction of acids and

bases. Salicylic acid (pure) will turn purple if FeCl3 is added, because salicylic acid has a

phenol group that will react with FeCl3. The melting point of salicylic acid is 159 C.

Making of Aspirin

Aspirin is an ester of acetic acid with salicylic acid. Therefore, this compound can be prepared by reacting salicylic acid with acetic anhydride using sulfuric acid as a catalyst. With reaction :

(Tim Dosen Kimia Organik Unesa, 2013)

In the manufacture of aspirin, salicylic acid (o-hydroxy benzoic acid) serves as the alcoholic and the reaction takes place on the hydroxyl group. The purity of aspirin could diuiji using iron (III) chloride. Before the purified aspirin do recrystallized aspirin beforehand in order to have a pure. Aspirin is used as a fever-lowering drugs, antibiotics, and pain relievers (analgenetika). Aspirin is usually sold as a sodium salt, which is sodium acetyl salicylate (Irdoni, 2010)

The purity of aspirin can be determined by testing the melting point, which should be pure aspirin melting point is 136 ° C. The purity of aspirin can also be tested using iron (III) chloride. Iron (III) chloride reacts with the phenol group of salicylic acid to form a purple complex. Iron (III) chloride is a yellow solution, if the sample is not a remaining salicylic acid sample pure of aspirin) then it will not react with salicylic acid, or color of sample is yellow, like the color of a solution of iron (III) chloride when added Iron (III) chloride.

VI. Tools and Materials

Recrystallization

Tools:

a. Erlenmeyer flask

b. Spatula

c. Buchner funnel

d. pippete

e. electric stove

f. Thermometer

Materials :

a. Salicilic acid

b. Aquades

c. Norit

1 gram salicylic acid

Result

Entered into Erlenmeyer flask 125 mLAdded 5 mL aquadestBoiled and shakedAdded some aquades until crystall is dissolved

Result

- Filtered using Buchner funnel in hot conditions- Cooled

- Filtered back with Buchner funnel- Dried in eksikator- Weighed

Mass =

- Measured the melting pointTemperature =

- Added drops of FeCl3Result

Making Aspirin

Tools:

a. Erlenmeyer flask

b. Spatula

c. Buchner funnel

d. Thermometer

Materials:

a. Salicilic acid

b. Anhidrate salisilic acid

c. concentrated sulfuric acid

d. Ethanol 96%

e. FeCl3 solution

f. Aquades

VII. Procedure

Recrystallization

2,5 gram Salicilic acidAlumunium

Result

- Put in a 125 mL Erlenmeyer- Added 3.75 grams of acetic acid anhydride- Added 3 drops of concentrated H2SO4- Stirred until homogeneous- Heated bath above 50o - 60o C while stirring 5 minutes- Cooled while stirring

- Added 37.5 mL of distilled water

- Filtered with Buchner funnel- Added 7.5 mL of 96% ethanol- Added 25 mL of distilled water- recrystallized- dried in eksikator

Result

Result

weighedMass =

Measures the melting pointTemperature =

Added drops of FeCl3

Result

Making Aspirin

VIII. Observation table

Recrystallization

Treatment Hypothesis Result ConclussionBefore After- Adding aquadest to salicylic acid and

boiled.

- Filtering the solution using Buchner

funnel

- Cooling the colorless filtrate

- Filtering the filtrate using Buchner funnel

- Weighing the crystall

- Measuring the melting point of crystall

- Adding FeCl3 to crystall

Salicylic acid dissolve in aquadest form colorless solution

We get residue and colorless filtrate.

Will form white crystal

The crystal left in filter paper

Mass of crystal is less than sample (<1gram)

The melting point of crystal is ± 159C

Crystal will reacts with FeCl3.The color of crystal changes to dark purple.3 C7H6O3 (aq) + FeCl3 (aq) ------> Fe(C7H5O3)3 (aq) + 3 HCl (aq)

Salicylic acid is white

crystal

The solution is colorless

The solution is colorless

We have colorless solution and crystal in it

Color of crystal = white

Color of FeCl3 = yellow

Form homogeneous

mixture (colorless) with

aquadest

There is little bit residue

and colorless filtrate

There is white crystall in solution

The white crystal left in filter paper

Mass = 0.8 gram

Temperature = 150C

The color of crystall changes to dark purple

The result is suitable with hypothesisWe get pure compound of salicylic acid

Making of Aspirin

Treatment Hypothesis Result ConclussionBefore After- Adding acetic anhydride acid and H2SO4

to salicylic acid and stirred.

- Boilliing the solution untill 50-60C

- Adding aquadest

- Filtering using Buchner funnel

- Recrystalizing the filtrate

- Weighing the crystal

- Measuring the melting point of aspirin

- Adding FeCl3 to crystal

Salicylic acid reacts with acetic anhydride acid form aspirin

The solution become white crystal

The crystal will dissolve form colorless solution

Will get residue and colorless filtrate

Will get white sharp crystal of aspirin

The mass of crystal is less than initial sample (<2.5gram)The melting point of aspirin is 136C

Aspirin is not react with crystal, so the color of crystal still white and FeCl3 solution is yellow

Salicylic acid is white

crystal

The solution is colorless

There is white crystal

The solution is colorless

There is colorless filtrate

Color of crystal = white

Color of FeCl3 = yellow

Form homogeneous

mixture react with acetic

anhydride acid

The solution become

white crystal

Crystal dissolve in water and form colorless solution

We get litlle bit residue and colorless filtrate

Formed white sharp crystal

Mass = 2.021 gram

Temperature = 134C

There is no color changing

The result is suitable with hypothesisWe get pure compound of aspirin

IX. Analysis

Recrystallization

The purpose of this experiment is to purifying salicylic acid from impurities by recrystallization. Firstly, We put 1 gram of crystal salicylic acid into Erlenmeyer flask and add 5 mL aquadest. Initially the crystal does not dissolve, but when we boil and stir it the crystal dissolve and form homogeneous mixture. And then we filter the solution using Buchner funnel and filter paper in hot condittion. We get little bit residue in filter paper and colorless solution as filtrate. It indicates the impurities left in filter paper.

Next step, we let the filtrate cool. And we can see the crystal formed in solution. We filter again the filtrate to get the crystal using Buchner funnel. So we get the white crystal in filter paper and we dry it in desiccator for three days.

After three days we weigh the crystal and get the mass of crystal is 0.8 gram, less than the mass of sample. It indicates the impurities have been separated and we get the pure crystal of salicylic acid. But, to prove it we measure the melting point of crystal that we have got. We get the current temperature melting crystals is 150C. The number of melting point our crystal is different with basic theory. And we do confirmation test by add FeCl3 to crystal and the crystal form dark purple solution. it indicates the crystal that we get contain salicylic acid and react with FeCl3 because there is –OH group in the salicylic acid that will react with FeCl3.

3 C7H6O3 (s) + FeCl3 (aq) Fe(C7H5O3)3 (aq) + 3 HCl (aq)

Making of Aspirin

The purpose of this experiment is to synthesis aspirin and purifying it from the impurities using cristallization method. Firstly, we put 2.5 gram salicylic acid to Erlenmeyer flask and add acetic anhydride acid and drops of sulfuric acid. The salicylic acid react with acetic anhydride acid form aspirin. Sulfuric acid that we added act as catalyst. We get the colorless solution of aspirin. With reaction :

Next step, we boil the solution in 50-60C for five minutes and let the solution cool. The solution changes to crystal. And then we added aquadest, the crystal dissolve in aquadest and form homogeneous mixture (colorless).

After we get the colorless solution of aspirin, we do recrystallization to separate aspirin from the impurities or salicylic acid that remain. And then we get white taper crystal of aspirin. And we dry it in desiccator for three days.

After three days we weigh the crystal and get the mass of crystal is 2.021 gram, less than the mass of sample. It indicates the impurities have been separated and we get the pure crystal of aspirin. But, to prove it we measure the melting point of crystal that we have got. We get the melting point of crystals is 134C. The number of melting point our crystal is close with the basic theory, 136C. And we do confirmation test by add FeCl3

to crystal, but there is no reaction occur the color of crystal still white and the color of FeCl3 solution still yellow. It indicates the crystal that we get does not contain salicylic acid because FeCl3 just can react with salicylic acid form dark purple solution. So the crystal that we have got is pure of aspirin.

X. Discussion

In this experiment we have difficulty to measuring the melting point of crystal that we have got. Because the crystal is easy to melt with small range of temperature. So, in the first experiment, recrystallization, we get the melting point of salicylic acid is different with basic theory. In basic theory the melting point of salicylic acid is 159C, but we just get 150C for our crystal. It caused by our accuracy in measure the melting point of crystal.

XI. Conclusion

From the data that we have got we can conclude that we got the pure crystal of salicylic acid in the first experiment by recrystallization method. With the melting point of salicylic acid is 150C and percentage of salicylic acid in sample is 80.0 %.

For the second experiment, making of aspirin. We can conclude that we got pure crystal of aspirin after react salicylic acid and acetic anhydride acid and continued with recrystallization process to separate crystal from impurities. The melting point of our crystal (aspirin) is 134C, It is too close with the melting point in basic theory, 136C. With the percentage of aspirin in sample is 80.8 %.

References

- Arsyad, M.Natsir. 2011, Kamus Kimia Arti dan Penjelasan Istilah, Gramedia,

Jakarta

- Irdoni, HS and Nirwana, HZ. 2009, Modul Kimia Organik, Universitas Riau,

Pekanbaru

- Tim Dosen Kimia Organik Unesa. 2013, Panduan Praktikum Kimia Organik, Unesa

Press, Surabaya

- Williamson. 1999, Macroscale and Microscale Organic Experiments, Houghton

Mifflin Company, USA

Attachment

picture explanation

1 gram salicilic acid add with 5 mL H2O

salicilic acid add with some H2O while heating until the salicilic acid dissolve completely

salicilic acid that completely dissolve filt by using buchner funnel

filtrate of salicilic acid that produce cooled in room temperature

filtrate of salicilic acid that have been cooled filt by using buchner funnel

the crystal of salicilid acid after put into desicator in 4 days. Pure of salicilid acid

crystal that produce have shape as needle but in the sort size

the crystal of aspirine after have been around the step of crystalization and put into desicator for 4 days.

the cystal that produce have shape as grains and soft texture.

crystal of aspirine

crystal of salicilid acid

crystal of aspirine in selinder pipe

the color of the top pipe is white

crystal of salicilid acid in selinder pipe

the color of th e top pipe is white

aspirine after occure the melting point test

the color of the top pipe is black

salicilid acid after accure the melting point test

the color of the top pipe is black

the melting point degree of aspirine is 1340C

the melting point of salicilid acid is 1500C

crystal of aspirine after added FeCl3

crystal of salicilid acdi after added FeCl3