5th
practical class IDENTIFICATION OF UNKNOWN DRUG
NAME: ALICIA VALLS ARRUFAT
SAMPLE: PHENAZONE
BEHAVIOUR OF COMPOUND DURING HEATING AND BURNING (describe what you should see during
the heating of your sample in burner and choose one of possibility):
We should see carbonization, it will turn black; the compound will be burnt without a rest and it may
possible have an increase of volume, melt, release vapours that are flammable or sublimate.
ORGANIC/INORGANIC/ORGANIC-INORGANIC COMPOUND
ELEMENTARY ANALYSIS (write down the reactions of tests you should do and mark which of them
should be positive):
1- NITROGEN à POSITIVE à BLUISH – GREEN PRECIPITATE OR BLUE SOLUTION
Corg. + Norg. à CN-
6CN+
Fe2+
à [Fe(CN)6]4-
[Fe(CN)6]4+
Fe3+
à {FeIII
[FeII
(CN)6]}-
2- SULPHUR à NEGATIVE à NOT BLACK SOLUTION OR BLACK PRECIPITATE
Sorg. à S2-
S2+
Pb2+
à PbS
3- HALOGENS à NEGATIVE à NOT HEAVY, WHITE, YELLOWISH OR YELLOW PRECIPITATE OF
SILVER HALIDE
4- CHLORINE, BROMIDE, IODINE à NEGATIVE
• CHLORINE à NOT WHITE PRECIPITATE EASILY SOLUBLE IN DILUTE AMMONIA
AgCl + 2NH3 à [Ag(NH3)2]+Cl•
BROMIDE à NOT YELLOWISH PRECIPITATE, WHICH IS HARDLY SOLUBLE IN DILUTE
AMMONIA, BUT IT IS SOLUBLE IN CONCENTRATED AMMONIA
AgBr + 2NH3 à [Ag(NH3)2]+Br•
IODINE à NOT YELLOW PRECIPITATE INSOLUBLE IN BOTH DILUTE AND CONCENTRATED
AMMONIA
AgI + 2NH3 [Ag(NH3)2]+I-
5th
practical class IDENTIFICATION OF UNKNOWN DRUG
SOLUBILITY (decide according to the information in Ph. Eur.):
Very soluble in water, in ethanol (96 per cent) and in methylene chloride.
pH of solution/suspension (decide according to nature of your sample): my sample is acid.
REACTIONS FROM THE FLOWCHARTS (write down your “flowcharts pathway”; describe results of
your hypothetical analysis – reactions from the flowcharts you can find in material called
“Identification of an unknown drug”):
1. Unknown compound, organic or inorganic? Organic compound.
2. Elementary analysis. Contains C, H, O; C, H, O, N or C, H, O, N, S? Contains C, H, O, N.
3. Soluble in water or insoluble in water? Soluble in water.
4. Reaction with sodium nitritre:
We dissolve 0,05g of the compound in distilled water. After that, we take 5ml of the solution
and add a few drops of dilute sulphuric acid and a crystal of sodium nitrite. The colour of the
solution changes to blue- green.
Phenazone (d) + H2SO4 (d) + 2NaNO2 (s) à Blue - green solution
5. We have had a positive reaction so we stop the process here.
IDENTIFICATION REACTIONS (from your monography choose the tests necessary for identification of
your substance and describe them):
First identification:
A. Melting point: from 109ºC to 113ºC
B. Infrared absorption spectrophotometry.
Second identification:
A. Melting point: from 109ºC to 113ºC
C. To 1ml of the Solution S (prepared dissolving 2,5g in CO2 free – water and diluting to 50ml
with the same solvent) we have to add 4ml of water R and 0,25ml of dilute sulfuric acid R. After
that we have to add 1ml of sodium nitrite solution R and a green colour will develop.
D. To 1ml of the solution S we have to add 4ml of water R and 0,5ml of ferric chloride solution
R2. A red colour develops which is discharged on the addition of dilute sulfuric acid R.