practical manual py-203

PRACTICAL MANUAL

2010-11

Organic Chemistry-I

PY - 203

CENTRAL INDIA INSTITUTE OF PHARMACY, Indore.

LIST OF PRACTICALS:

1. Purify the given organic compounds by distillation.

2. Purify the given organic compounds by recrystillazation.

3. Introduction to the use of stereo models.

4. Synthesis, Purification, Characterization (by using Solubility, Melting Point,

T.L.C. and percentage purity) of organic compounds and percent yield

calculations of the following compounds:

a) 2, 4, 6-trinitro phenol (Picric acid) from phenol

b) Iodoform from ethyl alcohol

c) 2, 4, 6-tribromoaniline from aniline

d) 2, 4, 6-tribromo phenol from phenol

e) Phenylbutazone from phenol

f) Benzanilide from aniline

g) Phthalidimide from phthalic anhydride

h) Thiourea

i) Phenyl urea

j) Flourescein

k) Methly orange

l) Methly red

Experiment No. 1

Aim: To determine and report the melting point of the given sample.

Reference: 1. Brain Furnis S., Antony Hannaford J., Peter Smith W.G., Vogel’s Textbook of

practical organic chemistry, Fifth edition, page no …….(2004).

Requirements: Theils Tube, Burner, Thermometer, Capillary Tubes.

Principle: Melting point serves as a criterion of purity of an organic compound. Ions or

molecules in a crystalline solid are arranged in a regular geometric fashion. Melting point occurs

when a temperature is reached at which the thermal energy of the particles is great enough to

overcome the intercrystelline forces that hold them together. A pure organic compound usually

has a sharp and definite melting point.

Theory:

Procedure:

1. Seal the capillary tube at one end by keeping 2-3 mm of capillary tube in Bunsen flame

contact and continuously rotating it till the end is completely sealed by forming a bulb at

the end.

2. Now fill the capillary with compound the melting point of which is to be determined,

about 0.05 g of compound is placed on the plate and open end is then gently tapped.

3. Tie the capillary tube with thermometer and place the whole in Theil’s tube filled with

liquid paraffin.

4. Now put Bunsen flame under the tube constantly and properly.

5. Note the temperature at which the compound starts melting and then note the temp. at

which it completely melts( both the temp. should not vary more than the range of 2 C.

Take the average of the two temperatures.

Result:

Experiment No. 2

Aim: To determine and report the boiling point of the given sample.

Reference: Brain Furnis S., Antony Hannaford J., Peter Smith W.G., Vogel’s Textbook of

Practical Organic Chemistry, Fifth edition, page no.…….(2004).

Requirements: Theils Tube, Burner, Thermometer, Capillary Tubes, Fusion tubes.

Principle: In a liquid, the particles are not arranged in a regular manner and are thus free to

move. A liquid boils when a temperature is reached at which the thermal energy of the particles

is great enough to overcome the cohesive forces that hold them together. This is the point at

which the vapour pressure of the liquid becomes equal to the atmospheric pressure. Boiling point

of the liquid is significant for a particular compound.

Theory:

Procedure:

1. Take the ignition tube.

2. Now fill the tube with liquid sample to 1/4 th of the tube

3. Tie the ignition tube with thermometer and place the whole in Theil’s tube filled with

liquid paraffin (Take care that ignition tube should be out of liquid paraffin).

4. Now put Bunsen flame under the tube constantly and properly.

5. Note the temperature at which the compound starts boiling.

Result:

Experiment No. 3

Aim: To determine and report the solubility behavior of the given sample.

Reference: Brain Furnis S., Antony Hannaford J., Peter Smith W.G., Vogel’s Textbook of

Practical Organic Chemistry, Fifth edition, page no.…….(2004).

Requirements: Test tubes, test tube stand, stirrer, burner and test tube holder.

Principle: The solubility of the molecule depends on several intermolecular forces such as ion

dipole, solvent-solute, solvent-solvent, etc. A compound dissolves in water if it can form

hydrogen bonds with water. During dissolution of a solid or liquid, the ions or molecules

separate out and the spaces in between them are taken up by the formation of new bonds between

solvent and the solute particles. In general the solubility of organic compound gives valuable

information regarding it’s chemical nature.

Theory:

Procedure:

1. Take few test tubes and label them as A, B, C, D……. & so on.

2. To the first test tube add sample and water, shake well and observe the solubility.

3. To the second test tube add ether, shake well and observe the solubility.

4. Take Ethanol as a solvent and observe solubility in another test tube.

5. Take 5% NaOH solution and sample and check the solubility.

6. Take 5% NaHCO3 and check the solubility.

7. Take 5% HCl and observe the solubility.

8. Take concentrated H2SO4 and sample and observe the solubility of the given sample.

Result:

Experiment No.4

Object: To synthesize and characterize Picric acid.

References: 1. Vogel Arthur I; 'Elementary Practical Organic Chemistry'; II edition; 2004,

pg.313.

2. Vogel furniss B.S.; Hannaford A.J.; Smitt P.W.G.; TAF chell A.R.; Text book of practical

organic chemistry; 5th edition, 2004,pg.1256.

Requirements:

Chemical requirements:

Phenol 5 gm

Conc. H2SO4 6.5 ml

Conc. HNO3 19 ml

Yield 8 gm

Apparatus requirements:

Round bottom flask, water bath, ice bath and funnel.

Theory:

Reaction:

OH

+ H2SO4

HNO3

OH

NO2O2N

NO2Phenol

Picric acid

Procedure:

1. In 500ml round bottom flask, place 5gm of phenol and 6.5ml conc. H2SO4 .

2. Shake and heat the contents on water bath for 30 min.

3. When a dry solution of o- and p- phenol sulfonic acid is obtained, cool the flask in an ice

bath.

4. Add 19ml of conc. HNO3 at room temperature, drop by drop with continuous shaking.

5. Allow the reaction mixture to stand for sometime and when brisk evolution of brown fumes

stops, heat the flask on water bath for 2 hrs. with occasional stirring.

6. Cool the reaction mixture and add 100ml of water.

7. Filter off the yellow crystals of picric acid. Wash thoroughly with water to remove all HNO3.

Recrystallize the product with dil. alcohol.

8. The yield of pure picric acid is 8 gm.

Observation:

Color:

Odor:

Appearance:

M.P.:

Theoretical yield:

Practical yield:

% yield:

Result:

Experiment No. 5

Object: To synthesize & characterize Methyl orange.

References: 1. Vogel AI. Elementary Practical Organic Chemistry, Part 1: Small Scale

Preparation. 2nd ed. Delhi, CBS publications & Dist., 2004, Page no………

Requirements:

Glasswares & Apparatus: Mortar and pestle, 250 ml conical flask, beaker, thermometer, filter

paper, Buchner Funnel & Vacuum Filtration assembly.

Chemicals: Sulphanilic acid dihydrate : 5.25 g ; Sodium carbonate (anhydrous) : 1.35 g ;

Sodium nitrite : 1.9 g ; HCl (conc.) : 5.25 ml ; Dimethylaniline : 3.025 g : Glacial acetic acid

1.5 ml ; Sodium hydroxide solution [20% (w/v)] : 17.5 ml ; and Sodium chloride : 5.0 g.

Procedure:

1. Grind together in a mortar 0.581 g of Phthalic anhydride & 0.85 g of resorcinol.

2. Transfer mixture to a 250 ml conical flask.

3. Heat flask in air bath to 180 oC.

4. Weigh 0.27 g anhydrous ZnCl2, grind to coarse powder in a mortar (protect from

moisture)

5. Add it in small portions to above solution with stirring when temp. reaches 180 oC.

6. Continue stirring until dark mass becomes so viscous that further stirring is not

practicable (40-45 min).

7. Allow temp. to fall to 90 oC & add 7.75 ml of water & 0.38 ml conc. HCl, & then heat

flask until water boils.

8. Stir the mixture & continue heating until the reaction mixture has disintegrated & all the

zinc salts have dissolved.

9. Filter off insoluble fluorescein at the pump, grind it with water in a mortar & filter again.

10. Dry at 100 oC.

Yield of pure fluorescein: 1 g

(may be purified by dissolving in dil. NaOH, filter & then precipitating with dil HCl,

filtering, washing & drying.)

Theory:

Observation & Calculation:

Result:

Experiment No. 06

Aim: To Prepare and characterised Benzanilide (N-Benzoylaniline) from Aniline (Schotten-

Bauman Reaction).

Reference:

Requirements: aniline, sodium hydroxide, benzoyl chloride

Theory:

Reaction Mechanism:

Procedure:

In a 250 ml conical flask take 5 ml aniline, add 50 ml of 10% sodium hydroxide solution and 7

ml benzoyl chloride. Cork the flask and shake vigorously for 15 minutes when crude benzanilide

separates out as white solid. The flask gets warmed as the reaction is exothermic. The

completion of the reaction is indicated by the disappearance of pungent smell of benzoyl

chloride. Add about100 ml cold water and filter the precipitated product. Wash it with cold water

and recrystallise from alcohol.

Calculation:

Result:

Theoretical Yield-

Practical Yield -

% Yield -

Melting point -

Experiment No. 07

Aim: To Prepare and submit Phthalimide from Phathalic Anhydride.

References:

1. Furniss, B.S.; Hannaford, A.J.; Smith, P.W.G.; Tatchell, A.R.; “Textbook Of Practical Organic

Chemistry” fifth edition, Pearson Education, London, p. no.1065-1066, 898.

Requirements:

Phthalic anhydride: 99 gm

Urea: 20 gm

HCl

Benzene

Theory:

A) The starting material phthalic anhydride is first converted into the cyclic imide,

phthalimide by treatment with aqueous ammonia or urea.

B) The cyclic imide ring of phthalimide is opened by alkaline hydrolysis in the first

step of the reaction to give the sodium salt of the phthalimidic acid ( half amide of

phthalic acid)

Procedure:

A) Intimately mix 99 gm of pure phthalic anhydride and 20 gm (0.33 mol) of urea, and

place the mixture in a 1-litre, long necked, round bottomed flask. Heat the flask in an oil bath at

130-135. when the contents have melted, effervences commences and gradually increases in

vigour. After 10-20 m, the mixture suddenly froths up to about three times the original

volume.and becomes almost solid. Remove from bath and allow to cool and add conc. HCL until

precipitation of the o-tolueic acid is complete.when cooled filter off the o-tolueic acid with

suction and wash with a little cold water. Recrystallize from benzene. M.P. 102-103oC

Yield – 5 gm.


Results:

Experiment No. 8

Object: To synthesize & characterize fluorescein dye.


Preparation. 2nd edition Delhi, CBS publications & Dist., 2004, p. 370.

Requirements:

Glasswares & Apparatus: Mortar, 250 ml conical flask, beaker, thermometer, filter paper,

Buchner Funnel & Vacuum Filtration assembly.

Chemicals: 0.581 g of Phthalic anhydride, 0.85 g of resorcinol, 0.27 g anhydrous ZnCl2, 0.38 ml

conc. HCl.

Theory:

Procedure:

1. Grind together in a mortar 0.581 g of Phthalic anhydride & 0.85 g of resorcinol.

2. Transfer mixture to a 250 ml conical flask.

3. Heat flask in air bath to 180 oC.

4. Weigh 0.27 g anhydrous ZnCl2, grind to coarse powder in a mortar (protect from

moisture)

5. Add it in small portions to above solution with stirring when temp. reaches 180 oC.

6. Continue stirring until dark mass becomes so viscous that further stirring is not

practicable (40-45 min).

7. Allow temp. to fall to 90 oC & add 7.75 ml of water & 0.38 ml conc. HCl, & then heat

flask until water boils.

8. Stir the mixture & continue heating until the reaction mixture has disintegrated & all the

zinc salts have dissolved.

9. Filter off insoluble fluorescein at the pump, grind it with water in a mortar & filter again.

10. Dry at 100 oC.

Yield of pure fluorescein: 1 g

(may be purified by dissolving in dil. NaOH, filter & then precipitating with dil HCl, filtering,

washing & drying).


Results:

Experiment No. 9

Object: To synthesize & characterize Thiourea.


Preparation. 2nd edition Delhi, CBS publications & Dist., 2004, p……

Requirements:

Theory:

Chemical Reaction:

NH4SCN S = C (NH2)2

Ammonium Thiocynate Thiourea

Procedure:

1. The 16.5 gm ammonium thiocynate is melted in around flask in a paraffin-bath, and kept

temperature at which the mass remains just liquid 1700C for I hours.

2. The cooled melt is powdered and ground with 20 ml of cold water which dissolve

unchanged ammonium thiocynate but little of the thiourea.

3. Dissolving the residue in a littile hot water pure thiourea is obtained, on cooling, in

colourless silky needles, M.P. 1720C.

4. Recrystallised by hot water.


Results:

Experiment No. 10

Object: To synthesize iodoform from ethyl alcohol.


Preparation. 2nd edition Delhi, CBS publications & Dist., 2004, p….

Requirements:

Glasswares: Round bottom Flask, Beaker, Funnel, thermometer.

Chemicals: Ethyl alcohol, sodium carbonate, iodine, NaOH.

Theory:

Chemical Reaction:

Cl3CH2OH + 4I2 + 6NaOH CHI3 + HCOONa + 5NaI + 5H2O

Ethyl alcohol Iodoform

Procedure:

1. Take 20 ml ethyl alcohol, 40 gm sodium carbonate and 20 ml water in 500ml round

bottom flask.

2. Heat the flask to about 70-800C on a water bath, to the warm solution.

3. Add small amount of Iodine at a time with constant shaking.

4. Add more iodine so that the reaction product should have a pale yellow colour.

5. Add dropwise a dil. Solution of NaOH, if any brown colour of iodine persists.

6. Filter the crude iodoform, wash with cold water and recrystalise from hot ethanol to

obtain a yellow crystal, M.P. 1190C.


Results:

practical manual py-203

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