RIYADH COLLEGE OF DENTISTRY AND
PHARMACY
LEVEL V-PHARMACY STUDENTS
MEDICINAL CHEMISTRY -I
LAB NOTEBOOK
FIRST SEMESTER
2007-2008
COURSE DIRECTOR:
DR.MAHA ELHAKEEM
Name: _____________Student No.:______________
1
RIYADH COLLEGE OF
DENTISTRY AND
PHARMACY
Level V
PHRM 312
Lab -1
Identification Of Functional group (COOH, and phenolic OH),SALICYLIC ACID
APPARATUS AND CHEMICALS:
Test Tubes, Test tube Rack, Test tube Holder, Gloves, Filter paper, Dropper,
Small Beaker, Burner. Distilled Water, salicylic acid, Sodium hydroxide solution,
Hydrochloric acid, Sodium bicarbonate 10%, Ferric chloride soln.,litmus soln.,
hexamine, conc sulfuric acid
PROCEDURE
Experiments
Observation
Inferences
1. The physical state of the
compound was noted.
Colourless
crystalline solid.
2. 0.2g compound + 2ml H20 in
cold and hot. State
Insoluble in cold
but soluble in hot
state.
Coloured compounds like quinones,
some amines and phenols etc.
absent.
Aliphatic acids of low Mol. wt.,
aliphatic amides, carbohydrates
absent. Aromatic acid, amine, or
phenol may be present
An acidic compound indicated.
3. The aqueous mixture from
The colour
test (2) + 2-3 drops of Litmus changed from blue
solution
to red.
4. The compound was dissolved
Soluble.
in 10%NaOH.
5. The solution from test 4 was
compound
acidified with HCl.
reprecipitated.
6. The 1g compound treated
CO2 evolved.
with 10% NaHCO3 solution.
7. The compound treated with
Violet colored
Ferric chloride solution.
solution.
8. The 0.2g compound was
Smoky flame.
burnt in flame on the tip of a
spatula.
9. The 1g compound treated crimson red colour
with hexamine in a dry porcelin
dish.
It may be an acid or a phenol.
It may be an aromatic acid or a
phenol.
Phenol absent and a carboxylic
acid indicated.
Benzoic acid may be present.
An aromatic carboxylic acid
present.
salicylic acid is indicated.
2
Level V
PHRM 312
Lab -2
RIYADH COLLEGE OF
DENTISTRY AND
PHARMACY
Name: _____________Student No.:______________
Identification Of Functional group (Phenol), PHENOL
APPARATUS AND CHEMICALS:
Test Tubes, Test tube Rack, Test tube Holder, Gloves, china dish, Filter paper,
Dropper, Small Beaker, Burner. Distilled Water, Phenol, Sodium hydroxide solution,
Hydrochloric acid, Conc.H2SO4, 10%NaNO2, bromine water.
PROCEDURE:
Experiments
Observation
Inferences
1. The physical state of the
Coloured
Coloured compounds like
compound was noted.
compound
quinones, some amines and
phenols etc. present.
2. 0.2g compound + 2ml H20 in
Insoluble in cold
Aromatic acid, amine, or phenol
cold and hot. State
but soluble in hot may be present (Aliphatic acids
state.
of low Mol. wt., amides, &
carbohydrates absent).
3. The aqueous mixture from
The colour
An acidic compound indicated.
test (2) + 2-3 drops of Litmus changed from blue
solution
to red.
4. The compound was dissolved in
Soluble.
It may be an acid or a phenol.
NaOH.
5. The solution from test 4 was
compound reIt may be an aromatic acid or a
acidified with HCI.
precipitated.
phenol.
6. The compound was treated
CO2 not evolved.
Phenol indicated
with 10% NaHCO3 solution.
, carboxylic acid absent.
7. Dilute soln. of compound + 2Violet coloured
May be phenol or resorcinol
drops of Ferric chloride solution.
solution.
8. 0.2g of compound was burnt in
Smoky flame.
An aromatic compound present
flame on the tip of a spatula.
9. 1g soln of phenol in water, add
Impart yellow
slowly Bromine water with color to mixture.
shaking.
10. 5ml Phenol + 1 drop NaNO2 A ring green below
10% + 2-5ml conc.H2SO4 along
& red above
surface
formed
Phenol present.
Phenol indicated.
3
RIYADH COLLEGE OF
DENTISTRY AND
PHARMACY
Level V
PHRM 312
Lab -3
Name: _____________Student No.:______________
Identification Of Functional group (Amines), Aniline
APPARATUS AND CHEMICALS: Test Tubes, Test tube Rack, Test tube Holder,
Gloves, fusion tube, china dish, Filter paper, Funnel, Dropper, Small Beaker,
Burner. Distilled Water, aniline, sodium metal, Sodium hydroxide solution, Ferrous
sulfate soln, Hydrochloric acid, Dil. Sulfuric acid, Chloroform, ice, sodium nitrite
soln, 2-Naphthol, Sodium Hydroxide 10%, Bromine water.
PROCEDURE:
Experiments
1. The physical state of the
compound was noted.
2. 0.2g compound + 2ml H20 in
cold and hot. State
Observation
Colourless liquid when
pure, but turns brown on
standing.
Insoluble in cold but
soluble in hot state.
3. The aqueous mixture from The colour changed from
test (2) + 2-3 drops of Litmus
red to blue.
solution
4. The compound dissolved in in
Soluble and & re-ppt
dil H2SO4, or HCl.
with NaOH soln.
5. The 0.2g compound was burnt
Smoky flame.
in flame on the tip of a spatula.
6.Diazotisation Test. 0.2 gm
A brilliant red dye is
compound + 1ml conc.HCl +
produced.
3 ml H2O, Cool with ice + few
drops of NaNO2 soln. Add this
Diazonium soln in cold 2Naphthol in excess of 10% NaOH
soln.
7.Bromine water Test: compound
White ppt of
soln + Br2 water.
Tribromoaniline formed
Inferences
Coloured compounds like
quinones, some amines and
phenols etc. present.
Aromatic acid, amine, or
phenol may be present.
A basic compound indicated.
It may be an amine.
An aromatic compound
present.
Aromatic amine confirmed.
Aniline (C6H5NH2)
confirmed.
4
RIYADH COLLEGE OF
DENTISTRY AND
PHARMACY
PHARMACY
Level V
PHRM 312
Lab -4
Name: _____________Student No.:______________
Identification Of Functional group (COOH),BENZOIC ACID
APPARATUS AND CHEMICALS:
Test Tubes, Test tube Rack, Test tube Holder, Gloves, Filter paper, Dropper,
Small Beaker, Burner. Distilled Water, benzoic acid, Sodium hydroxide solution,
Hydrochloric acid, Sodium bicarbonate 10%, Ferric chloride soln.,litmus soln.,
hexamine, conc sulfuric acid
PROCEDURE
Experiments
Observation
Inferences
1. The physical state of the
compound was noted.
Colourless
crystalline solid.
2. 0.2g compound + 2ml H20 in
cold and hot. State
Insoluble in cold
but soluble in hot
state.
Coloured compounds like quinones,
some amines and phenols etc.
absent.
Aliphatic acids of low Mol. wt.,
aliphatic amides, carbohydrates
absent. Aromatic acid, amine, or
phenol may be present
An acidic compound indicated.
3. The aqueous mixture from
The colour
test (2) + 2-3 drops of Litmus changed from blue
solution
to red.
4. The compound was dissolved
Soluble.
in 10%NaOH.
5. The solution from test 4 was
compound
acidified with HCl.
reprecipitated.
6. The 1g compound treated
CO2 evolved.
with 10% NaHCO3 solution.
7. The compound treated with Buff precipitate is
Ferric chloride solution.
formed
8. The 0.2g compound was
Smoky flame.
burnt in flame on the tip of a
spatula.
It may be an acid or a phenol.
It may be an aromatic acid or a
phenol.
Phenol absent and a carboxylic
acid indicated.
Benzoic acid may be present.
An aromatic carboxylic acid
present.
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Level V
PHRM 312
Lab - v
RIYADH COLLEGE OF
DENTISTRY AND
PHARMACY
Name: ____________________ Student number:______________________
Scheme for identification of organic compounds
Apply the following chemical tests in the following order:
1- physical state of compound: solid crystala or liquid
2- solubility in cold and hot water
3- if soluble in cold water then reprecipitates with dil acid, it may be
sodium salicylate or sodium benzoate.
4- solubility in dilute HCl and 10%NaOH
A-if solution is soluble in NaOH and acidic by litmus solution,
-Carry the effervescence test with NaHCO3
-carry FeCl3 test:
If violet, it may be phenol or salicylic acid
If buff ppt, it may be benzoic acid
If blood red color with violet, it may be sodium slicylate
B-if the solution is basic and soluble in HCl and gives no positive color
FeCl3, so carry out the diazotization test
Unknown compound may be one of:
1-phenol
2-benzoic acid
3-salicylic acid
4-aniline
5-sodium benzoate
6-sosium salicylate
6
Identification Of UNKNOWN COMPOUND
THE UNKNOWN COMPOUND IS ----------------------------------------AND ITS STRUCTURE IS ----------------------------------------------.
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Final Lab exam
Aspirin LAB
Preparation, identification and assay of ASPIRIN
Preparation of aspirin:
Add 1.5 mL of acetic acid anhydride and 0.3 mL of concentrated
sulphuric acid to 1 gm of salicylic acid.
Warm the reaction mixture for 30 minutes at 50-60 C with frequent
stirring.
Pour down the contents into cold water (15 mL) with occasional stirring
and filter off the crude aspirin.
Recrystallize the product as the following:Dissolvethe product in
alcohol (3 mL) and pour the solution into warm water (7.5 mL).
If a solid separates, warm the mixture to dissolve the solid . the clear
solution is allowed to cool slowly to get needle shaped crystals of
aspirin. Calculate the yield and check the melting point.
Identification tests of aspirin:
Principle of the test:
This test is based on the hydrolysis of aspirin into salicylic acid and
acetic acid as shown, where salicylic acid gives deep violet colour with
ferric chloride solution due to presence of phenolic group. Acetic acid
in the filtrate which forms ester ethylacetate by heating with alcohol
in the presence of suphuric acid.
8
Procedure of test:
1-Boil 0.1 gm of aspirin with 10 mL of 0.1 N NaOH for 5 minutes.cool
and acidify with 10 mL dilute sulphuric acid. White ppt is produced and
the odour of acetic acid is perceptible.
2-Filter the ppt , dissolve in water and add ferric chloride solution, a
deep violet colour is produced.
3- add 3 mL alcohol and 3 mL of sulphuric acid into the filtrate and
warm. The odour of ethylacetate ester is perceptible.
CH3COOH + C2H5OH → CH3COO-C2H5
H2SO4
Acetic acid ethyl alc
ethylacetate ester
Assay of prepared aspirin:
Principle of assay (back titration):
On boiling with known excess of standard sodium hydroxide solution,
aspirin is hydrolyzed into salicylic acid and acetic acid. The liberated
acids react with sodium hydroxide to form sodium salts. At the end
point, a slight excess of the base reacts with the indicator to produce
colour change.
Procedure:
Add 50 mL of 0.5 N NaOH standard solution to 1 gm of prepared
aspirin, and boil for 10 minutes. Cool the solution and titrate the
excess unreacted amount of alkali with 0.5 N HCl standard solution
using phenolphthalein as indicator.------(E)
Perform a blank titration in the same way. -----(B)
Calculate the percentage purity according to the following equation:
% purity= (B-E) X FX 100/ 0.3
F: 1 mL 0.1 N NaOH is equivalent to 0.009008 gm aspirin.
9
Thin Layer Chromatography (TLC):
It is an analytical procedure used to identify and separate similar
compounds using TLC plate and an elution system.
1- Preparing the elution system (10 mL of 0.5 % acetic anhydride in
ethylacetate) in the jar and allow to saturate.
2- Preparing the TLC plates with pencil and ruler.
3- Spotting 3 compounds dissolved in acetone (salicylic acid,
prepared aspirin and commercial aspirin) using capillary tubes.
4- Place the TLC plate in the jar and allow to run.
5- Record the Rf values in your report and compare them.
The Rf value = distance traveled by the compound divide by the solvent
front.
Melting point measurement:
Measure the melting point for the same above compounds using a
melting point apparatus. Record your results in your report.
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