LABORATORY MODULE
ERT 102
Organic Chemistry
Sem I 2012/2013
Pn. Saleha Shamsudin
Pn. Rozaini Abdullah
Pn. Azduwin Khasri
Cik Hafizah Mohd Johar
En. Mohd Qalani Che Kasim
Pn. Sriyana Abdullah
School of Bioprocess Engineering
Universiti Malaysia Perlis
CONTENTS
CONTENTS
2
PREFACE
3
LABORATORY SAFETY
4
FORMAT OF LAB REPORT
6
EXPERIMENT 1
: Reduction of Camphor with Sodium Borohydride
8
EXPERIMENT 2
: Dehydration of Alcohol
17
EXPERIMENT 3
: Synthesis, Purification and Quantification of Ester
24
EXPERIMENT 4
: Synthesis of Aspirin
36
EXPERIMENT 5
: Separation of Organic Dye Stuff using Thin Layer
Chromatography (TLC) Technique
45
2
PREFACE
This module is to serve as a guidance and reference material for students who are
registering for Organic Chemistry. It will be used by students for laboratory practices and
it will help them to understand the subject in an effective manner.
There are four (5) experiments that need to be performed by the students. All of the
experiments are being designed to help student in comprehending the subject of
Organic Chemistry
It is hoped the module is user friendly and that students would enjoy the laboratory work
thereby increasing their awareness of the importance of the subject.
3
LABORATORY SAFETY MANUAL
Safety in the laboratory requires the same kind of continuing attention and effort that is
given to research and teaching. The use of new and/or different techniques, chemicals,
and equipment requires careful preparation. Reading, instruction, and supervision may
be required, possibly in consultation with other people who have special knowledge or
experience.
Each individual who works in a laboratory has a responsibility to learn the health and
safety hazards associated with the materials to be used or produced, and with the
equipment to be employed. It is important for you to know what is expected of you and
what your responsibilities are with regard to safety to yourself, your colleagues and our
environment. In addition, there are safety practices and safety equipment with which you
must be thoroughly familiar if you are to work safely in the laboratory. This manual
should be used as a guide to the general types of hazards.
Some of the more basic safety practices that you are expected to follow are:
1.
Do not perform unauthorized experiments.
2.
Upon entering the laboratory note the location of the closest fire extinguisher,
first aid kit, eye wash station and chemical shower. Their location will be
specified on the laboratory door.
3.
DO NOT TOUCH MOVING COMPONENTS while the machine is in operation
4.
Use a hood for hazardous, volatile, and noxious chemicals.
5.
A laboratory coat or apron should be worn while working in the laboratory. In
general, shorts, skirts, brief tops, and sandals are not safe. Further
clarification of clothing requirements should be directed to the person(s) in
charge of the laboratory in which you are working. Confine all loose clothing,
ties, and long hair. Leave your jewellery at home.
6.
Do not wear contact lenses in the laboratory. Fumes, gases, and vapors can
easily be absorbed by the lens or trapped between the lens and eyes
resulting in chemical burns or abrasive injury.
7.
Do not work alone in a laboratory. It is unsafe and not recommended.
4
8.
You are further expected to secure all gas cylinders, to label all containers, to
observe and obey all posted signs.
Users should understand and follow all the laboratory safety instruction while using the
laboratory. The rules and regulations will be no used without your commitment and
cooperation.
5
FORMAT OF LABORATORY REPORT
The purpose of the laboratory report is to provide information on the obtained results,
analysis and interpretation and discussion of the results. The discussion and conclusions
are definitely significant in a report because these sections deliver the knowledge you
gained upon doing the experiments.
For this particular laboratory, the following format is suggested:
1. Cover page
2. Objective
3. Introduction/ theory
4. Results
5. Discussion
6. Conclusion
The template of the lab report is attached in the lab module.
Detailed descriptions of every item are given below:
1.
Cover page
It should have the course name and number, the number and title of the
experiment, group number and names of the team members and as well as the
date of the report delivery.
2.
Objective
It should state main objective of this experiment.
3.
Introduction/ Theory
Some of the background and theory for this experiment needs to be state. Do not
repeat or copy introduction from lab module.
6
5.
Results
This section deals with the management of data obtained after experiment. Data
can be presented as a series of figures, tables, etc with descriptive text and
numbered but no discussion. The best presentation of some data is graphical.
Figures should be numbered. Each figure must have a caption following the
number. All graphs, beside captions, should have clearly labeled axes.
6.
Discussion
This section must emphasize on discussing the outcome of the experiment. It
can be written in two ways:
a)
Compare the expected outcome of the experiment with theory or
b)
Make an appropriate graph on which the theory is represented and
experimental data by points.
A critical part of discussion is error analysis. In comparison of theory and
experiment you may not get a perfect agreement. It does not necessarily mean
that your experiment was failed. The results will be accepted, provided that you
can account for discrepancy. Precision and accuracy of the instrument or your
ability to read the scales may be one limitation. A part from this, data analysis
requires you to open your mind and critical approach to your work and that
routine methods may not be sufficient.
7.
Conclusion
The conclusions should contain several shorts statements closing the report.
They should inform the reader if the experiments agreed with the theory. If there
were differences between measured and expected results, explain possible
reasons for these differences. You may also say what could have been done
differently, how experiments may be improved, or make other comment on the
laboratory report.
7
EXPERIMENT 1
Reduction of Camphor with Sodium Borohydride
1.
2.
OBJECTIVE :
1.1
To reduce ketone and producing alcohol
1.2
To determine the reaction selectivity in producing preferred reaction
product
CORRESPONDING COURSE OUTCOMES
CO1: Ability to EXPLAIN the basic concepts theoretically and APPLY the
knowledge of the physical and chemical properties of each functional group.
3.
INTRODUCTION
3.1
The reduction of an organic compound is an extremely important general
processes. Reduction can involve: a) The addition of 2H across a double
bond or triple bond, e.g C=C, C=O and C=NR; b) Or the replacement of a
functional group such as OH or halide by H. The addition or transfer of
hydride followed by a proton, usually in work-up. This is normally
accomplished using a hydride transfer reagent, and is a common method
of reducing polarized multiple bonds.
3.2
Hydride-transfer reagents are commonly used as reducing agents in
organic synthesis. The two reagents most frequently used are lithium
aluminium hydride (LiAlH4) and sodium borohydride (NaBH4), and
although both the reagents can be regarded as a source of nucleophilic
hydride, their reducing powers are quite different.
3.3
Lithium aluminium hydride is a powerful reductant and reduces most
functional groups which contain a polarized multiple bond; it reacts
vigorously with water and must be used in dry solvents and under
anhydrous conditions.
3.4
In contrast, sodium borohydride is a milder reducing agent and shows
considerable selectivity and, although it reduces acid chlorides, aldehydes
and ketones rapidly, esters and other functional groups are only slowly
reduced or are inert under the same conditions. It is usually used in protic
solvents such as methanol and ethanol.
8
Figure 2.1: Chemical reaction showing reduction of camphor with sodium
borohydride
4.
APPARATUS/CHEMICALS/MATERIAL :
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5.0
5.1
5.2
5.3
5.4
5.5
Camphor
dry methanol
conical flask
sodium borohydride
sample tubes
water bath
ice water
100cm3 beaker
universal indicator paper
dilute hydrochloric acid
glass rod
diethyl ether
separating funnel
magnesium sulfate
gas chromatography
9
6.
PROCEDURE:
6.1
Dissolve the camphor (1g) in 5cm3 of dry methanol in a 25cm3 conical
flask.
6.2
Weigh out the sodium borohydride (0.3g) cautiously into a sample tube.
6.3
Then add the sodium borohydride intermittently to the camphor solution
(with swirling) over a period of 10-15 minutes.
6.4
Let the reaction stand at room temperature, with occasional swirling, for
about 30 minutes.
6.5
Then, heat to boiling point and maintain this temperature for 2-3
minutes(use a water bath in the fume cupboard; do not allow the mixture
to boil to dryness)
6.6
Pour the hot mixture onto~ 10g ice held in a 100 cm3 beaker.
6.7
Stir until most of the ice has melted.
6.8
Very cautiously make the reaction acidic (to universal indicator paper) by
adding dilute hydrochloric acid.
6.9
Stirring with a glass rod during the addition of the acid is essential to
ensure thorough neutralization and destruction of unused sodium
borohydride.
6.10
Add 25cm3 of diethyl ether, stir to dissolve any solids and transfer into
separating funnel.
6.11
Separate the ether layer and extract the aqueous layer with 2 further
portions of ether.
6.12
Combine the ether extracts, dry over magnesium sulfate and remove the
solvent to give the crude product.
6.13
Run a gas chromatographic analysis on your crude products.
10
7.
8.
9.
RESULTS:
7.1
Mass of the crude product :
7.2
Mass of camphor:
DISCUSSION & EVALUTION /EXERCISES:
8.1
Discuss the mechanism of sodium borohydride reduction of ketones in
ethanolic solution.
8.2
Draw the structure of the major isomer you obtained by reduction of
camphor.
8.3
Explain why this is the major isomer obtained.
8.4
Discuss the gas chromatogram of the crude product (include the original
gas chromatogram into your laboratory report)
8.5
What factors affect the approach of hydride towards ketonic camphor?
CONCLUSION:
Based on the experimental procedure done and the results taken, draw a simple
conclusion to this experiment.
11
SCHOOL OF BIOPROCESS ENGINEERING
UNIVERSITI MALAYSIA PERLIS
ERT 102: ORGANIC CHEMISTRY
EXPERIMENT 1
: REDUCTION OF CAMPHOR USING SODIUM
BOROHYDRIDE
Name
: _______________________________________
Matric No.
: ____________________________________
Group Members
: _____________________________________
_____________________________________
_____________________________________
_____________________________________
Date of experiment: __________________________________
Date of submission: __________________________________
12
1.0 OBJECTIVE:
2.0 THEORY:
13
3.0
RESULTS:
3.1
Mass of the crude product :
3.2
Mass of camphor:
4.0 DISCUSSION:
14
5.0
QUESTIONS
5.1
Discuss the mechanism of sodium borohydride reduction of ketones in
ethanolic solution.
5.2
Draw the structure of the major isomer you obtained by reduction of
camphor.
5.3
Explain why this is the major isomer obtained.
5.4
Discuss the gas chromatogram of the crude product (include the original
gas chromatogram into your laboratory report)
5.5
What factors affect the approach of hydride towards ketonic camphor?
15
6.0
CONCLUSION:
16
EXPERIMENT 2
Dehydration of an Alcohol
1.
2.
OBJECTIVE:
1.1
To convert the alcohol to alkenes via dehydration process
1.2
To determine the purity of the alkene
CORRESPONDING COURSE OUTCOMES
CO2: Ability to EXPLAIN theoretical organic chemical reactions of alkenes,
alkynes and alkyhalides at molecular level.
3.
INTRODUCTION
3.1
The dehydration of an alcohol is one of the most important C-O bond
reactions. During a dehydration reaction a carbon-oxygen bond and a
neighboring carbon hydrogen bond is broken. The breaking of these
bonds then results in the formation of an alkene pi bond.
Strong concentrated mineral acids such as sulfuric acid and phosphoric
acid are often utilized to perform alcohol dehydration. Strong acids can
protonate an alcoholic hydroxyl group, which allows it to dissociate as
water. Loss of a proton from the intermediate brings about the alkene.
3.2
In this experiment the alcohol 4-Methyl-cyclohexanol will be dehydrated.
The equilibrium of this reaction will be shifted in favor of the product by
distillation. During the distillation the product will be removed, along with
water, as it is formed. However, the starting material can also be distilled
if the distillation is not done carefully.
3.3
The product will be purified by extraction, which will remove any
phosphoric acid that may have distilled with the product. The extraction
will also aid in removing water. The product is then distilled a second time
to separate it from any remaining alcohol. The purity of the alkene will be
determined using gas chromatography.
17
4.
5.
APPARATUS/CHEMICALS/MATERIAL :
4.1
Simple distillation apparatus
4.2
Round bottom flask
4.3
Concentrated phosphoric acid
4.4
Sulfuric acid
4.5
4-Methylcyclohexanol
4.6
Boiling chips
4.7
Saturated sodium chloride
4.8
Anhydrous sodium sulfate
PROCEDURES
5.1
Set up a simple distillation. Use a 50ml round bottom flask as the receiver
flask.
5.2
Place 15 ml of 4-Methylcyclohexanol in a pre-weighed 25 ml round bottom
flask. Reweigh the flask to determine the exact weight of the alcohol. Add
2-3 glass beads to the distillation flask.
5.3
Add 4.0 ml of concentrated phosphoric acid and 60 drops of sulfuric acid
to the distillation flask. Attach the distillation flask to the apparatus and
immerse the receiving flask in an ice bath.
5.4
Distill the product as slowly as possible while monitoring the temperature.
Continue heating until no more liquid is collected or the temperature rises
above 140°C.
5.3
After the distillation is complete, remove the collection flask and keep it in
the bench top hood. Transfer the distillate to a 125ml separatory funnel.
Wash the product with 4 -5 ml of saturated sodium chloride. Allow the
layers to separate, drain the aqueous layer and discard it.
5.4
Pour the organic layer (product) into a 25 ml Erlenmeyer flask. Dry the
product over anhydrous sodium sulfate.
NOTE: The product can be stored in the hood over anhydrous sodium
sulfate until the next lab. When using the Erlenmeyer flask stopper it with
a cork NOT a rubber stopper.
18
6.
7
8
5.5
After the product is dried assemble a simple distillation apparatus. The
apparatus needs to be clean and dry. Use a 50 ml round bottom flask for
distilling and pre-weighed 25 ml round bottom flask as the receiving flask.
Add a few boiling chips to the distillation flask.
5.6
Immerse the receiving flask in ice bath. Start the distillation and collect the
product that distills over the range of 100-105C. Record the observed
boiling point. Re-weigh the receiving flask and determine the percent
yield.
5.7
Determine the purity of the product by analysis.
RESULT
6.1
The boiling point of the alkene
6.2
Percentage yield of alkene.
QUESTIONS
7.1
What is the name of alkene produced? Find the application.
7.2
Write the chemical reaction in the experiment.
DISCUSSION
Discuss the result from the distillation and gas chromatography.
9
CONCLUSION
Based on the experimental procedure done and the results taken, draw
some conclusions to these experiments
19
SCHOOL OF BIOPROCESS ENGINEERING
UNIVERSITI MALAYSIA PERLIS
ERT 102: ORGANIC CHEMISTRY
EXPERIMENT 2
: DEHYDRATION OF ALCOHOL
Name
:_______________________________________
Matric No.
: ____________________________________
Group Members
: _____________________________________
_____________________________________
_____________________________________
_____________________________________
Date of experiment: __________________________________
Date of submission: __________________________________
20
1.0
OBJECTIVE:
2.0
THEORY:
21
3.0
RESULTS:
3.1
The boiling point of the alkene
3.2
Percentage yield of alkene.
4.0 DISCUSSION:
22
5.0
6.0
QUESTIONS
5.1
What is the name of alkene produced? Find the application.
5.2
Write the chemical reaction in the experiment.
CONCLUSION:
23
EXPERIMENT 3
Synthesis, Purification and Quantification of Ester
1.
2.
OBJECTIVE
1.1
To synthesize ester from carboxylic acid and alcohol reaction
1.2
To purify ester through distillation
CORRESPONDING COURSE OUTCOMES
CO1: Ability to EXPLAIN the basic concepts theoretically and APPLY the
knowledge of the physical and chemical properties of each functional
group.
3.
INTRODUCTION
Esters are naturally abundant and readily synthesized, but all have the same
following structure.
O
C
R
OR'
Every day fragrances, such as the “rich smell’ of fresh ground coffee, are a
combination of esters (>200 identifiable esters found so far in coffee!). However,
some esters are readily recognized by their very characteristic flavor or odor.
In the table below, several examples of esterification products are given.
Table 1
Combinations of carboxylic acids and alcohols resulting in esters
Ester
Structure
Fragrance
Carboxylic
acid
Formic acid
Iso-butyl
formate
HCO2CH2CH(CH3)2
Raspberry
essence
Propyhl
acetate
CH3CO2CH2CH2CH3
Octyl
acetate
Ethyl
butyrate
Alcohol
Iso-butanol
Pear
essence
Acetic acid
1-propanol
CH3CO2CH2(CH2)6CH3
Orange
essence
Acetic acid
octanol
CH3CH2CH2CO2CH2CH3
Pineapple
essence
Butyric acid
ethanol
24
Methyl
butyrate
CH3CH2CH2CO2CH3
“Apple like”
essence
Butyric acid
methanol
In esterification reaction, esters can be prepared by reversible, acid-catalyzed,
combination of a carboxylic acid with an alcohol. Because it is reversible, the reaction
must be shifted to the product side by using excess reagent, or removing one of the
products. This reaction is also limited by any steric hindrance in the carboxylic acid or
the alcohol. The general equation for an esterification is shown below.
O
+
C
R
4.
R'
OH
O
H+
+ H2O
C
OH
R
OR'
EQUIPMENT / APPARATUS
4.1
Reflux apparatus
4.2
Isoamyl Alcohol
4.3
Acetic acid
4.4
parafilm
4.5
distilled water
4.6
round bottom flux
4.7
stopper
4.8
rotary evaporator
4.9
10% Na2CO3
4.10
Sodium sulphate Na2SO4
4.11
gas chromatography
25
5.
PROCEDURES
5.1
Part A – Synthesis of the ester
5.1.1
Take a 250 mL round bottom flask and thae column condenser as
shown in the Figure. Clamp the round bottom flask and top of the
condenser so that there is enough room to raise or lower the
heating mantel under the flask.
5.1.2
Be sure to measure volume of the following reagents to the
nearest 0.2 mL and wear goggles and gloves.
5.1.3
Under the fume hood take 15 mL of isopentyl alcohol (also called
isoamyl alcohol or 3-methyl-1-butanol) in the clean, dry 250-mL
round-bottomed flask from the reflux setup. Add 20 mL of glacial
acetic acid. Then, carefully add 4 mL of concentrated sulfuric acid
to the contents of the flask, with swirling.
5.1.4
Add about 4-8 boiling chips to the mixture. Boiling chips or other
materials such as glass beads are always added to prevent
superheating or "bumping" when doing a reflux or distillation.
5.1.5
Heat the mixture under reflux (slow boil) for 30 minutes, then
remove the heating source and allow the mixture to cool to room
temperature.
retort stand
clamp
water out
water in
heating
mantle/heater
Figure 4.1: Refluxing of alcohol and carboxylic mixture
26
5.2
Part B – Purification of the ester
5.2.1
Pour contents of the reaction flask into the separatory funnel.
5.2.2
Add 20 mL of water to the separatory funnel. Differentiate the
aqueous and organic layer.
5.2.3
Collect the organic layer and wash them twice with 8 mL of 10%
Na2CO3
5.2.4
Dry the organic layer over anhydrous sodium sulfate.
5.2.5
Swirl the mixture from time to time over 10 minute-period. Then
allow the sodium sulfate to settle and transfer the organic layer
into a clean and dry container.
5.2.6
Place your sample in a 100 mL round bottom flask. Your teaching
engineer will show you how to use the rotary evaporator.
5.2.7
After removal of the methylene chloride, place your sample in a 50
mL round bottom flask. Record the boiling point of the ester.
Collect it in a clean container.
*Safety precautions
*H2SO4 is very corrosive; if it comes in contact with your skin, flush immediately with
large amounts of water. Although
*Less corrosive than H2SO4, acetic acid is also corrosive and should be rinsed
immediately off the skin.
*Chemical like methylene chloride is mild irritants and/or poisonous if ingested in large
amounts and skin contact and inhalation of vapors should be avoided.
*Several reagents used are flammable; do not use flames in this lab. Wear gloves and
protective clothing.
6.
RESULTS AND DISCUSSION
5.1
The boiling point of ester:
27
7.
QUESTIONS
7.1
Write the chemical reaction between the reactants in the experiment. Find
the equilibrium constant.
7.2
What is the name of the ester produced? Find the application.
7.3
Why did you wash your product with methylene chloride? What was the
purpose of washing with water?
7.4
Explain the function of the acid catalyst in a Fisher Esterification reaction.
7.5
Determine the yield of the ester.
28
8.
DISCUSSION:
Discuss the results you gained from the gas chromatography.
29
9.
CONCLUSION:
Based on data and discussion, make your overall conclusion by referring to the
experimental objective.
30
SCHOOL OF BIOPROCESS ENGINEERING
UNIVERSITI MALAYSIA PERLIS
ERT 102: ORGANIC CHEMISTRY
EXPERIMENT 3
: SYNTHESIS, PURIFICATION AND
QUANTIFICATION OF ESTER
Name
: _______________________________________
Matric No.
: ____________________________________
Group Members
: _____________________________________
_____________________________________
_____________________________________
_____________________________________
Date of experiment: __________________________________
Date of submission: __________________________________
31
1.0 OBJECTIVE:
2.0 THEORY:
32
3.0
RESULTS:
3.1
4.0
The boiling point of ester:
DISCUSSION:
33
5.0
QUESTIONS
5.1
Write the chemical reaction between the reactants in the experiment. Find
the equilibrium constant.
5.2
What is the name of the ester produced? Find the application.
5.3
Why did you wash your product with methylene chloride? What was the
purpose of washing with water?
5.4
Explain the function of the acid catalyst in a Fisher Esterification
reaction. Determine the yield of the ester
34
6.0
CONCLUSION:
35
EXPERIMENT 4
Synthesis of Aspirin
1.
2.
OBJECTIVE:
1.1
To synthesize aspirin
1.2
To determine the yield or fraction of the theoretical amount which can be
prepared
1.3
To confirm the purity of the product by measuring its melting point
CORRESPONDING COURSE OUTCOMES
CO4: Ability to FORMULATE the knowledge of organic chemical process in
industry such as production of biopharmaceuticals
3.
INTRODUCTION
3.1
Aspirin is the first drug that was clinically tested before it was marketed in
1899. It reduces headache pain (analgesic), reduces fever (antipyretic),
relieves the swelling and joint pain associated with rheumatism and
arthritis (anti inflammatory), and enhances the elimination of uric acid
(uricosuric).
Aspirin can be synthesized by the reaction of salicylic acid and acetic
anhydride. Salicylic acid is easily synthesized and available. It can be
extracted from the bark of the willow tree or from the meadowsweet plant
and had been used since ancient times. Acetic anhydride results from the
elimination of acetic acid and a common reagent. The starting materials
are easily available and inexpensive. The reaction becomes:
HO
O
C
CH3
O
CH3
C
C
O
O
OH
+
Acetic Anhydride
HO
Salicylic acid
O
C
O
CH3
+
CH3
OH
C
C
O
O
Acetic Acid
Acetyl salicylic acid,
aspirin
36
The conditions under which the reaction could be conducted depend on
some of the properties of the reactants and the products. Acetic anhydride is
a liquid at room temperature and boils at the temperature well above 100 . It
reacts with water to form acetic acid- the reverse of the reaction shown
above for its formation. Salicylic acid and aspirin are both solids that melt at
temperatures well above 100 . They are slightly soluble in cold water.
4.
5.
APPARATUS/CHEMICALS/MATERIALS:
4.1
salicylic acid
4.2
acetic anhydride
4.3
concentrated sulfuric acids
4.4
beakers
4.5
wire gauze
4.6
filter paper
4.7
clamp
4.8
buchner conical flask
4.9
Instrument for melting point determination
4.10
watch glass
4.11
ice water
PROCEDURE:
5.1
Since this experiment involves the usage of an anhydrous compound, the
material should be dried in the drying machine.
5.2
Set up the temperature water bath in the range of 70-80 oC. Begin heating
the water bath. Monitor the level of distilled water added to water bath is
adequate.
5.3
Weigh 3.0 g of salicylic acid and place it in a 250 ml Erlenmeyer flask.
5.4
In the hood, transfer 6.0 ml of acetic anhydride into the 250 ml
Erlenmeyer flask using a pipette.
5.5
In the hood, add 5 drops of concentrated sulfuric acid to the Erlenmeyer
flask using the dropper provided.
37
5.6
Bring the flask to the desk and place it in the extension clam as shown in
Figure 4.1. Make sure that the reaction mixture is below the water level in
the water bath and that the water is boiling. The water bath is boiled for
about 20 minutes (70-80 ).
clamp
Erlenmeyer flask
water bath
distilled water
reaction mixture
Figure 4.1: Experimental setup for the reaction
5.7
Allow the flask to cool to room temperature, add 25ml of water and cool
the mixture in an ice bath.
5.8
While the flask is chilling, prepare a gravity filtration apparatus.
5.9
Weigh a piece of filter paper on a watch glass. Record the weight of
the paper and the watch glass.
5.10
Place the weighed paper in the Buchner funnel. Wet the paper with a
small amount of water using your wash bottle to seal the paper to
the funnel surface.
5.12
Transfer the filter paper and the product to a clean 150 ml beaker by
inserting a clean spatula under the bottom of the filter paper to peel it
away from the funnel. Dry the product and weigh it.
5.13
Measure the melting point and compare to the value of pure aspirin of
138-140 .
38
6.
RESULTS:
6.1
Weight of Empty Watch Glass……………………….___________g
6.2
Weight of Salicylic Acid………………………………___________g
6.3
Volume of Acetic Anhydride…………………………____________ml
6.4
Volume of Concentrated Sulfuric Acid……………...___________drops
6.5
Time of Heating……………………………………….___________min
6.6
Total amount of water added to product……………____________ml
6.7
Weight of Filter Paper + Product……………………____________g
6.8
Weight of Dry Filter Paper………………………….._____________g
6.9
Weight of Product………………………..…………_____________g
6.10
Theoretical Yield (based on limiting agent)………_________g
6.11
Percent Yield……………………………………….___________%
6.12
Melting point of product…………………………...____________
.
Percent of Yield (%) = Actual yield
x 100%
Theoretical yield
7.
8.
DISCUSSION & EVALUTION /EXERCISES:
7.1
Discuss the yield of synthesized aspirin. What could have been done
to improve the yield?
7.2
Show the mechanisms of aspirin synthesis
CONCLUSION:
Based on the experimental procedure done and the results taken, draw
some conclusions to these experiments
39
SCHOOL OF BIOPROCESS ENGINEERING
UNIVERSITI MALAYSIA PERLIS
ERT 102: ORGANIC CHEMISTRY
EXPERIMENT 4
Name
: SYNTHESIS OF ASPIRIN
: _______________________________________
Matric No.
: ____________________________________
Group Members
: _____________________________________
_____________________________________
_____________________________________
_____________________________________
Date of experiment: __________________________________
Date of submission: __________________________________
40
1.0 OBJECTIVE:
2.0 THEORY:
41
3.0
RESULTS:
3.1
Weight of Empty Watch Glass……………………….___________g
3.2
Weight of Salicylic Acid………………………………___________g
3.3
Volume of Acetic Anhydride…………………………____________ml
3.4
Volume of Concentrated Sulfuric Acid……………...___________drops
3.5
Time of Heating……………………………………….___________min
3.6
Total amount of water added to product……………____________ml
3.7
Weight of Filter Paper + Product……………………____________g
3.8
Weight of Dry Filter Paper………………………….._____________g
3.9
Weight of Product………………………..…………_____________g
4.0
Theoretical Yield (based on limiting agent)………_________g
4.1
Percent Yield……………………………………….___________%
4.2
Melting point of product…………………………...____________
.
Percent of Yield (%) = Actual yield
x 100%
Theoretical yield
42
4.0
DISCUSSION & EVOLUTION/EXERCISES
4.1 Discuss the yield of synthesized aspirin. What could have been done
to improve the yield?
4.2 Show the mechanisms of aspirin synthesis
43
5.0
CONCLUSION:
44
EXPERIMENT 5
Separation of Organic Dye Stuff Using Thin Layer Chromatography (TLC)
Technique
1.
OBJECTIVE :
1.1
2.
To visualize the location of the separated component on the plate
CORRESPONDING COURSE OUTCOMES
(CO2) Ability to DEFINE, DISCUSS and APPLY the chemical and physical
properties of each functional group and APPLY theoretical reactions at molecular
level
3.
INTRODUCTION
3.1
Thin layer chromatography is a technique to separate a complex mixture
containing liquid and solid organic compound. This separation technique
involves partitioning of the analyte compound between the silica gel at the
aluminium plate and the mobile solvent phase that travels upwards the
plate. The ratio of the distance which the analyte travels over the distance
that the solvent phase travels is the Rf value. The Rf value can be used to
identify the compound.
Rf = Distance from start to centre of substance spot (dA)
Distance from start to front solvent (dP)
4.
APPARATUS/ CHEMICALS/MATERIAL :
4.1
Aluminium plate
4.2
Beakers
4.3
Capillary tube or melting point tubes
4.4
Organic dye stuff like bromocresol purple and rodamine B
4.5
Hexane
4.6
Acetone
4.7
Petroleum ether
45
5.
PROCEDURE:
5.1
Prepare 3 aluminium plates.
5.2
Using a sharp pencil, draw a straight line horizontally across the plate and
about 10 mm height from below the plate.
5.3
Make 2 spots of equivalent distance from each other on the straight
line.
5.4
Dip a capillary tube into the bromocresol purple solution.
5.5
On the 3 aluminium plates, make a contact between the dipped capillary
tube and the exact first spot of each plate. The quantity of liquid inside
the capillary tube should be minimum.
5.6
Leave the spots to dry.
5.7
Repeat the dropwise addition for the second and third time.
5.8
Ensure that each drop size is minimized.
5.9
Using a new capillary tube, drop rodamine B solution onto the second
mark on each aluminium plate three times.
5.10
Repeat the procedure.
5.11
Prepare 3 beakers containing solvents of about 5 mm deep as shown
in Table 3.1.
5.12
Pour the solvent mixture 1 into the first beaker. Solvent mixture 2 into the
second beaker and solvent mixture 3 into the third beaker. These beakers
should be closed at all times to ensure vapour saturation inside them.
5.13
Put one plate, with the spots below into one of the beaker containing the
solvent.
5.14
Put the lid on the beaker and allow the solvent travels until 0.5 cm from
the upper end of the plate.
5.15
Remove the plate and using a pencil, mark the front solvent.
5.16
Leave the plate to dry.
5.17
Calculate the Rf value for each spots of the 3 plates.
5.18
Use the middle spot for measurement.
46
Table 3.1: Mixture of mobile solvent phase
Solvent
Hexane (ml)
Acetone
Petroleum
(ml)
Ether(ml)
Mixture 1
1
4
2
Mixture 2
2
2
4
Mixture 3
2
4
2
Lid
Front solvent
Thick paper
wet by mobile
phase
TLC plate
Solvent
A
B
C
dA
.
a) Separation container
6.
dp
Origin
b) TLC plate
RESULTS:
Plate
Rf value
bromocresol
purple
rodamine B
Plate 1
Plate 2
Plate 3
47
Plate
Observation
bromocresol
purple
rodamine B
Plate 1
Plate 2
Plate 3
7.
DISCUSSION & EVALUTION /EXERCISES:
7.1
7.2
8.
Which solvent is the most suitable to produce good resolution?
Compare the Rf values of bromocresol purple and rodamine B.
CONCLUSION:
Based on the experimental procedure done and the results taken, draw some
conclusions to these experiments.
Safety precaution:
1. Make sure that you do not accidentally drop any organic compound on the plate.
48
SCHOOL OF BIOPROCESS ENGINEERING
UNIVERSITY MALAYSIA PERLIS
ERT 102: ORGANIC CHEMISTRY
EXPERIMENT 5: SEPARATION OF ORGANIC DYE STUFF THIN
LAYER CHROMATOGRAPHY (TLC)
Name
:_______________________________________
Matric No.
: ____________________________________
Group Members
: _____________________________________
_____________________________________
_____________________________________
_____________________________________
Date of experiment: __________________________________
Date of submission: __________________________________
49
1.0
OBJECTIVE:
2.0
THEORY:
50
3.0
RESULTS:
Rf value
Plate
Bromocresol
purple
Rodamine B
Plate 1
Plate 2
Plate 3
Plate
Observation
Bromocresol
purple
Rodamine B
Plate 1
Plate 2
Plate 3
51
4.0
DISCUSSION:
5.0
QUESTIONS
5.1 Which solvent is the most suitable to produce good resolution?
5.2 Compare the Rf values of bromocresol purple and rodamine B.
52
6.0
CONCLUSION:
.
53