Supplementary Information
List of chemicals and CAS numbers
S1
Pre-lab questions
S2
Experimental Procedure
S4
List of Mixtures
S8
Assessment Rubric
S13
List of chemicals and CAS numbers
Chemical
Diethyl ether
Dichloromethane
Sodium hydroxide
Hydrochloric acid
Sodium hydrogen carbonate
Sodium chloride
p-nitrobenzoic acid
ethyl 4-nitrobenzoate
D,L-phenylalanine
N-Acetyl-D,L-phenylalanine
N-Acetyl-D,L-phenylalanine methyl ester
2,6-dimethylaniline
α-Chloro-2,6-dimethylacetanilide
Paracetamol
Ethyl benzoate
4-aminophenol
Salicylic acid
4-methoxyacetanilide
Sesamol
Sesamol allyl ether
p-Anisidine
Benzoic Acid
Magnesium sulfate
S1
CAS number
60-29-7
75-09-2
1310-73-2
7647-01-2
144-55-8
7647-14-5
62-23-7
610-34-4
150-30-1
2901-75-9
62436-70-8
87-62-7
1131-01-7
103-90-2
93-89-0
123-30-8
69-72-7
51-66-1
533-31-3
19202-22-3
104-94-9
65-85-0
7487-88-9
Pre-Lab questions and results
The pre-lab questions were delivered and graded as a multiple choice quiz using
Blackboard. The quiz was available to the students from one week before the students were
scheduled to start this experiment until 12.00 am of the day of the experiment. Grades were
converted into a mark out of 10 and added to the assessment rubric. Answer’s to each
question is given in brackets after the answer.
Pre-lab quiz
Read through your script and watch the videos located in the experiment O6 folder. If you
haven’t done so already, look through the information about how to write your laboratory
report including the parts to complete before starting your experiment. Also read your
CHEM1000 notes by Professor Nelson about pKa and how solvent extractions work. When
you have done this answer the questions.
Check box to confirm you have understood the instructions
The following questions will help you with part 1 of the experiment – designing a purification
of a mixture.
1. What does the pKa value of a given compound represent?
a) The pH at which a molecule is fully dissociated
b) The pH at which a molecule is half dissociated (Answer)
c) The pH at which a molecule is not dissociated
2. What is the typical pKa value of a carboxylic acid?
a) 0
b) 5 (Answer)
c) 10
d) 15
3. What proportion of acetic acid and acetate would there be in a solution at pH 10?
a) all acetic acid
b) some acetate but mainly acetic acid
c) equal amounts of acetic acid and acetate
d) mostly acetate but some acetic acid
e) all acetate (Answer)
Feedback: Because a solution of pH 10 is several orders of magnitude higher than the pKa
value of acetic acid (4.7), it is fully dissociated.
4. A mixture of aspirin, aniline, paracetamol, and calcium chloride is partitioned between
diethyl ether and water. Which of these compounds will dissolve in the aqueous layer? Click
all that apply.
S2
a) aspirin (answer)
b) aniline
c) paracetamol
d) calcium chloride (answer)
5. A mixture of aspirin, aniline, paracetamol, and calcium chloride is partitioned between
diethyl ether and 2M sodium hydroxide solution. Which of these compounds will dissolve
in the aqueous layer? Click all that apply.
a) aspirin (answer)
b) aniline
c) paracetamol (answer)
d) calcium chloride (answer)
Feedback: CaCl2 is a salt so will dissociate in both water and 2M sodium hydroxide. The
carboxylic acid of aspirin has a pKa of 5, the phenol of paracetamol has a pKa of 10, and the
amine of aniline has a pKa of 35. Water has a pKa of 7 so aspirin partially deprotonate and
dissolve in the aqueous layer, whilst paracetamol and aniline will remain protonated and
soluble in the organic layer. Sodium hydroxide has a pKa value of 15 so it will fully
deprotonate both aspirin and paracetamol but not aniline.
6. Design a work-up flow chart and write this in your experimental write-up. This will be
checked by a demonstrator before you can start.
Check box to confirm you have understood the instructions
S3
Experimental Procedure
Reaction Overview
Design work-up procedure for a given reaction mixture
Previous Key Skills/Techniques required: solvent extraction, drying with MgSO4, using a
rotary evaporator, infra-red spectroscopy
New Key Skills/Techniques required: Experimental design, problem-solving.
As you have experienced, mixing together reagents is not the only important part of an
experiment. After this, products are separated from their impurities by a work up procedure
(often a solvent extraction) and sometimes further purification is also required, but how do
chemists design this part of the experiment?
To design a successful work-up procedure, the chemist must draw upon their knowledge of
the physical and chemical properties of molecules to manipulate the solubility of a chemical
in organic and aqueous solutions.
You will need to use your notes on purification and pKa in CHEM1000 ‘Modern Chemistry’
and Chapter 8 of ‘Organic Chemistry’ by Clayden, Greeves and Warren to help you through
this experiment.
Objectives and planning your work

You will purify a mixture of compounds by a liquid-liquid separation technique.

Each group will be given a different reaction mixture to design a work-up for. This can
be found in the O6 folder of the VLE.

In this experiment we are judging you on the purity of each compound, the yield is
not as important.
Pre-lab exercises
Your pre-lab exercises for this experiment are:

Complete the pre-lab exercises to help you become familiar with how to design a
work-up.

A work-up procedure you will design and use in this reaction. This must be
completed by the time you start your reaction.
S4
Designing your work-up
You will be given a mixture containing two or more organic compounds. You will use a
standard organic-aqueous work-up using a separating funnel [as you did in experiment O1]
to cleanly isolate the certain compounds in the mixture.
Which compounds will be in my mixture?
The mixture that you will be purifying is dependent on the week you are performing the
experiment. The list is available in the O6 folder of the VLE. Make sure you have chosen the
correct mixture of compounds to purify.
By using your knowledge of solubility and acidity, you should be able to manipulate which
components go into the aqueous or organic phase. We strongly recommend you answer
the questions 1-5 of the pre-lab quiz before designing your work-up.
You will have the following organic and inorganic solvents available to use:
Organic Solvents
Diethyl ether (Et2O)
Dichloromethane (DCM)
Aqueous Solutions
Water
2M NaOH (aq)
2M HCl (aq)
Saturated NaHCO3 (aq)
Brine (saturated NaCl) (aq)
S5
COSHH Assessment
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
Diethyl ether
Hazard
Extremely flammable liquid and
vapour.
Harmful if swallowed.
May cause drowsiness or
dizziness.
Possible carcinogen
Vapours may cause drowsiness
Irritant
Precautions
Wear gloves
Keep away from
flames/sparks/
hot surfaces
2M Sodium Hydroxide (aq)
Causes severe burns and eye
damage
Wear gloves
2M Hydrochloric acid (aq)
Corrosive
Harmful by inhalation
Wear gloves
Avoid breathing
vapours
Sodium hydrogen carbonate
Sodium chloride
Magnesium sulfate
No associated hazards
No associated hazards
No associated hazards
Dichloromethane
Wear gloves
Avoid breathing
vapours
Procedure
Your laboratory write-up will be slightly different to experiments O4 and O5. See the O6
folder in the VLE for further advice. Design your work up by constructing a flow chart in your
laboratory notebook.
You must have your work-up flow chart designed and signed by a demonstrator
before starting. Failure to do so will mean you cannot start your experiment.
To any organic solution containing one of the compounds you are trying to isolate, dry with
MgSO4, then remove the MgSO4 by filtration. Remove your solvent on a rotary evaporator.
Record a yield of your product.
Product __________ g; __________ %
Record an IR spectrum of your product [watch the video if you are unsure what to do] and
attach the spectrum to your laboratory notebook. Assign the peaks of the spectrum to your
product in the results section.
Transfer into a sample tubes (available in a drawer in your bay) and label the tube as shown:
S6
Your name
Course
Experiment O6: part 1
Compound name
Make sure you have isolated all the compounds you are required to and have an IR spectra
of each one.
Complete your laboratory report continuing from the pre-lab section.
Part 1 should include:

Your work-up flow chart

Your work-up written as an experimental procedure

A discussion of your purification procedure

Attached IR spectra and interpretation
CHECKLIST – make sure you have obtained all these before having your experiment
marked

Samples of all your products in labelled vials

Infra-red spectra of your products

Completed laboratory write up.
S7
List of mixtures
Make sure you are purifying the correct mixture based upon your start date of experiment
O6. Isolate the compounds that are boxed.
Week
Mixture
14
15
16
17
18
19
20
21
22
S8
Week 14 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
Hazard
Precautions
Harmful if swallowed.
Wear gloves
Irritating to the eyes.
p-Nitrobenzoic acid
Ethyl 4-nitrobenzoate
No associated hazards
N/A
Ethyl 4-aminobenzoate
No associated hazards
N/A
Week 15 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
Hazard
Precautions
D,L-Phenylalanine
No associated hazards
N/A
N-Acetyl-D,L-phenylalanine
Unknown
Wear gloves
N-Acetyl-DL-phenylalanine
methyl ester
Unknown
Wear gloves
S9
Week 16 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
Hazard
Precautions
2,6-Dimethylaniline
Flammable
Wear gloves
Toxic by inhalation, skin contact Avoid naked flames.
and if swallowed.
Handle in fumehood.
α-Chloro-2,6dimethylacetanilide
Irritant
Acetaminophen
(paracetamol)
Harmful
Wear gloves
Causes skin, eye and respiratory Avoid breathing dust
irritation.
Wear gloves
Week 17 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
4-Nitrobenzoic acid
Ethyl benzoate
Ethyl 4-aminobenzoate
Sodium Hydroxide pellets
Hazard
Harmful if swallowed.
Irritating to the eyes.
Precautions
Wear gloves
No associated hazards
N/A
No associated hazards
N/A
Causes severe burns and eye Wear gloves
damage
S10
Week 18 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
Hazard
Precautions
4-Aminophenol
Harmful by inhalation and if Wear gloves
swallowed
Avoid breathing vapours
Very
toxic
to
aquatic Avoid
release
to
organisms
environment
Suspected of causing genetic
defects.
Salicylic acid
Harmful if swallowed.
Wear gloves
Risk of serious damage to
eyes.
4-Methoxyacetanilide
Toxic by skin contact or if
swallowed.
the
N/A
Week 19 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
Hazard
Precautions
Sesamol
Irritant
Wear gloves
Sesamol allyl ether
Ethyl 4-aminobenzoate
Unknown
No associated hazards
S11
Wear gloves
Avoid inhalation
contact
N/A
and
skin
Week 20 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
Hazard
Precautions
p-Anisidine
Toxic by skin contact and if Wear gloves
swallowed.
Avoid inhalation of dust.
May cause cancer.
Very toxic to aquatic organisms
Salicylic acid
Harmful if swallowed.
Wear gloves
Risk of serious damage to eyes.
Ethyl benzoate
No associated hazards
N/A
Week 21 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
Hazard
Precautions
p-Anisidine
Toxic by skin contact and if Wear gloves
swallowed.
Avoid inhalation of dust.
May cause cancer.
Very toxic to aquatic organisms
4-Aminophenol
Harmful by inhalation and if Wear gloves
swallowed
Avoid breathing vapours
Very toxic to aquatic organisms
Avoid
release
to
the
Suspected of causing genetic environment
defects.
Benzoic acid
Irritant
Avoid breathing dust
Risk of serious damage to eyes
S12
Week 22 Mixture
COSHH Assessment
Section: Priestley Laboratory
Experiment: O6 – Experimental design
Personnel Involved: Undergraduates, laboratory demonstrators, laboratory staff
Chemical
D,L-Phenylalanine
Hazard
No associated hazards
N/A
Precautions
N-Acetyl-D,L-phenylalanine
Unknown
Wear gloves
N-Acetyl-DL-phenylalanine
methyl ester
Sodium Hydroxide pellets
Unknown
Wear gloves
Causes severe burns and Wear gloves
eye damage
Assessment Rubric
Pre-Lab exercise
Work-up flow chart
Part 1 product 1 appearance
Part 1 product 2 appearance
Part 1 product 1 IR quality
Part 1 product 1 IR assignment
Part 1 product 1 IR quality
Part 1 product 1 IR assignment
/10
In-lab Assessment
/10 Part 1 discussion of results
/10
/10
/7
/3
/7
/3
Total
Date
/60
S13
/10
Initials