M.Sc (ORGANIC CHEMISTRY) LABORATORY MANUAL
DEPARTMENT OF CHEMISTRY
RAJA BAHADUR VENKATA RAMA REDDY WOMEN’S COLLEGE (Autonomous) Affiliated to Osmania University Accredited by NAAC with ‘A’ Grade College with Potential for Excellence (Selected by UGC) Narayanaguda, Hyderabad, Telangana State
SYNTHESIS OF ORGANIC COMPOUNDS
INDEX
S. No Contents Page No.
1. Synthesis of Organic Compounds 1-31
2. Multi step synthesis of Organic Compounds 35-77
3. Isolation of Natural Products 79-85
4. Synthesis of Drugs 87-107
5. Separation of Organic binary & ternary mixtures 109-115
6. Qualitative Analysis of Organic Compounds 117-135
7. Spectral Analysis of Unknown Organic compounds 137-145
8. Chromatography 147-166
9. Estimation of Drugs 167-201
10. Microwave Assisted Organic Synthesis 202
CONTENTS
1. ACETANILIDE
2. P-BROMO ACETANILIDE
3. P-BROMO ANILINE
4. 2,4,6-TRIBROMO ANILINE
5. ASPIRIN
6. HIPPURIC ACID
7. TETRA-HYDRO CARBAZOLE
8. PHTHALIMIDE
9. META-DINITRO BENZENE
10. META NITRO ANILINE
11. ANTHRACENE-MALEIC ANHYDRIDE ADDUCT
12. 2,4- DIHYDROXY ACETOPHENONE
13. 7-HYDROXY-4-METHYL COUMARIN
14. AZALACTONE
Department of Chemistry, RBVRRWC 1 2017-2018
ACETANILIDE
General Reaction O
NH2 NH C CH3 O O CH3COOH CH COOH O 3
Aniline Acetic Anhydride Acetanilide
Mechanism
O O O O C C NH2 H2N CH CH O O 3 3
O O H O C NH C CH3 H3C N H C O CH3
CH3COOH
Acetanilide
Department of Chemistry, RBVRRWC 2 2017-2018
PREPARATION OF ACETANILIDE
Aim: To study N-acylation.
Principle: Aniline undergoes N-acylation with acetic anhydride in the presence of glacial acetic acid, preferentially attacking the nitrogen atom of aniline.
Reaction:N-acylation / N-acetylation / Electrophilic Substitution Reaction.
Chemicals: Aniline - 5mL
Glacial acetic acid - 5mL
Acetic anhydride - 5mL
Apparatus: R. B. Flask, Beaker, Water condenser.
Procedure: Transfer 5mLof Aniline into a clean & dry round bottomed flask, add 5mL of glacial acetic acid and 5mL of acetic anhydride. Add a porcelain piece and fix the water condenser and boil the mixture for 15 minutes on bunsen flame. Test for the completion of reaction by transferring a few drops of mixture into a beaker containing 100mL of cold water. If white precipitate is formed, it indicates that the reaction is completed. If no precipitate is formed continue heating for 10 more minutes and check for completion of the reaction.Then transfer the reaction mixture into beaker containing cold water & stir with a glass rod. Filter the compound under suction. Wash the precipitate with cold water & dry the sample.
Recrystallisation: Solvent-Hot water
M.P: 1140C
Department of Chemistry, RBVRRWC 3 2017-2018
Department of Chemistry, RBVRRWC 4 2017-2018
PREPARATION OF P-BROMO ACETANILIDE
Aim: To study the orientation of Electrophilic Substitution Reaction.
Principle: Aniline undergoes electrophilic substitution with bromine at 2, 4, 6 – positions to form tribromo aniline. To substitute selectively, the amino group has to be protected by acylation such that the bulky group restricts electrophilic substitution at ortho position because of steric hindrance & directs to para position.
Reaction : Electrophilic Substitution Reaction.
Chemicals: Acetanilide – 4gms
Glacial CH3COOH – 10mL
Bromine in glacial CH3COOH – 10mL
Apparatus: Conical flask, beaker &glass rod
Procedure: Dissolve 4gms of finely powdered acetanilide in 10mL of cold glacial acetic acid in a 250mL conical flask. In another small flask take 10mL of bromine in acetic acid and add this solution slowly into acetanilide solution until reddish orange colour persists. Shake the reaction mixture throughout the addition to ensure thorough mixing. Allow the final mixture to stand at room temperature for 15 minutes with occasional stirring. Then pour the reddish orange solution which may already contain some crystals of p-bromo acetanilide into a large amount of cold water, where upon p-bromo acetanilide will readily crystallizes out. Stir these crystals
thoroughly with water to eliminate CH3COOH & wash it with cold water & filter.
Recrystallisation: Solvent-Rectified Spirit
M.P: 163oC
Department of Chemistry, RBVRRWC 5 2017-2018
Department of Chemistry, RBVRRWC 6 2017-2018
PREPARATION OF P-BROMO ANILINE
Aim: To study hydrolysis of p-bromo acetanilide
Principle: p-bromo acetanilide undergoes hydrolysis in the presence of conc.HCl to form p-bromo aniline.
Reaction: Hydrolysis (deacylation)
Chemicals: Para bromo acetanilide – 4gms
Conc HCl-5mL
Ethyl alcohol – 8mL
5% NaOH
Apparatus: R.B. flask, water condenser
Procedure: Dissolve 4g of p-bromo acetanilide in 8mL of boiling ethanol contained in a 100mL round bottomed flask. Add 5mL of conc. HCl drop wise to the boiling solution. Reflux for 30-40 minutes. Dilute the reaction mixture with 50mL of water where by p-bromo aniline is formed. Neutralize the acidic solution with 5% NaOH until alkaline. Para bromo aniline separates as oil, which crystallizes by adding ice and filter.
Recrystallisation: Solvent-Alcohol
M.P: 66oC
Department of Chemistry, RBVRRWC 7 2017-2018
2,4,62,4,6 -T TRIBROMORIBROMO A NANILINEILINE General reaction NH NH2 2 Br Br
CH3COOH 3 Br2
Mechanism Br Formation of Electrophile
O O
H3C C OH H3C C O H
Br Br H H Br Br Electrophile Formation of Sigma Complex
NH2 NH2 NH2 NH2 NH2
Resonance hybrid Attack of Electrophile
NH 2 NH2 NH2 NH2
Br H Br H Br Br Br
NH2 NH NH 2 NH2 2 Br H Br Br Br
Br Br Br Br
NH2 Br NH2 NH2 Br H Br Br Br Br
Br Br
Br
2,4,6-TRIBROMO ANILINE 2,4,6 Tribromo aniline
Department of Chemistry, RBVRRWC 8 2017-2018
PREPARATION OF 2, 4, 6–TRIBROMO ANILINE
Aim: To study Electrophilic Substitution Reaction (bromination) on aniline
Principle: Aniline readily undergoes Electrophilic Substitution Reaction by involving the non-bonding electrons present on nitrogen. As
NH2group is Ortho& Para directing and also ring activating group there is an increase in electron density at ortho and para positions. Therefore aniline on bromination gives 2,4,6- tribromo aniline (i.e) bromination takes place at 2,4&6 positions.
Reaction:Electrophilic Substitution Reaction (Bromination)
Chemicals: Aniline – 5mL
Acetic acid – 19mL
Bromine in CH3COOH – 30mL. Apparatus: Beaker, Funnel, Measuring jar, Glass rod.
Procedure: Take 5mL of aniline and 19mL ofglacial acetic acid in conical
flask & keep this flask in ice bath and then add 30mL of Br2in acetic acid drop wise with constant stirring till orange colour of bromine persists. Allow the solution to stand at room temp for 15 minutes. Pour it into the cold water. 2,4,6-tribromo aniline precipitates out and filter.
Recrystallisation: Solvent- Ethyl Alcohol
M.P: 1200C
Department of Chemistry, RBVRRWC 9 2017-2018
ASPIRIN
General Reaction O OH O C CH COOH 3 O O COOH Conc. H2SO4 CH3COOH O
Salicylic Acid Acetic Anhydride Aspirin
Mechanism
H O O O O H O O
H O O H O O
O H O OH HO O O
HOOC HOOC HOOC
CH3COOH
- H
O
O C CH3 COOH
Aspirin
Department of Chemistry, RBVRRWC 10 2017-2018
PREPARATION OF ASPIRIN
Aim: To prepare aspirin by O-acylation
Principle: Salicylic acid undergoes acetylation with acetic anhydride selectively at the weakly acidic group (i.e.) phenolic group into
strongly acidic group in the presence of conc. H2SO4as catalyst. Reaction: Electrophilic Substitution Reaction /O-Acetylation / O-Acylation
Chemicals: Salicylic acid – 2gms
Acetic anhydride– 2.8mL
Conc.H2SO4- 2-3 drops
Apparatus: Conical flask, glass rod.
Procedure: Weigh about 2gms of salicylic acid and transfer into a clean conical flask and add 2.8mL of acetic anhydride and stir it with a
glass rod and add 2-3 drops of conc. H2SO4 and stir the mixture and warm on water bath to about 50-60oC for 15 minutes. Allow the mixture to cool and add about 50mL of water. Stir well and filter at the pump.
Recrystallisation: Solvent-Equal amounts of acetic acid and water
M.P:1360C
Department of Chemistry, RBVRRWC 11 2017-2018
-HCl HIPPURIC ACID
Genearal reaction
O O O Cl NaOH H2N H OH N O Benzoyl Chloride H Glycine Hippuric Acid O
Mechanism O
NaOOC CH2 O O O NaOH Ph Cl HN C Ph H2N NH2 OH H2O NaO H Cl
-HCl
CH2COONa O O HOH H HN C N NaOH HO
O Hippuric Acid
Department of Chemistry, RBVRRWC 12 2017-2018
PREPARATION OF HIPPURIC ACID
Aim: To study N-Benzoylation
Principle: Electrophilic substitution of benzoyl group on nitrogen atom of glycine gives N-Benzoyl glycine, commonly known as Hippuric acid.
Reaction: N-Benzoylation of glycine.
Chemicals: Glycine - 2.5gm
10% NaOH – 2.5mL
Benzoyl chloride – 4.5mL
Apparatus: Conical flask, glass rod,cork
Procedure: Dissolve 2.5 gms of glycine in 2.5mL of 10% NaOH solution taken in a conical flask (if not dissolved add few more mL of 10% NaOH) and add 4.5mL of benzoyl chloride in two portions to the solution. Stopper the flask and shake vigorously after each addition. Transfer the solution into a beaker containing water & filter it. If product is not formed, add crushed ice.
Recrystallisation: Solvent – Boiling water
M.P: 1870C
Department of Chemistry, RBVRRWC 13 2017-2018
TETRA HYDRO CARBAZOLE
General Reaction
AcOH NH NH2
O N H Phenyl Hydrazene Cyclohexanone Tetra Hydro Carbazole
Mechanism
Ph Ph H NH N Ph NH NH2 HN N O H H O HO
-H2O
H H H
N N HN N H H Ph
H H H
NH3 NH HN N H H2N
N H Tetra Hydro Carbazole
Department of Chemistry, RBVRRWC 14 2017-2018
PREPARATION OF TETRA – HYDRO CARBAZOLE
Aim: To study Fischer Indole synthesis.
Principle: Fischer Indolization occurs when phenyl hydrazine reacts with saturated cyclic aldehyde or ketone. Cyclization takes place with
loss of NH3 under the influence of reagents like glacial acetic acid. Phenyl hydrazine of saturated cyclic ketone like cyclohexanone undergoes cyclisation very rapidly when boiled with glacial acetic acid.
Reaction: Fischer Indole Synthesis.
Chemicals: Glacial acetic acid – 18mL
Cyclohexanone – 2.5mL
Phenyl hydrazine – 2.2mL
Apparatus: R. B. flask, Condenser
Procedure: Dissolve 2.5mL of cyclohexanone in 18mL of glacial acetic acid in a R.B. flask. Add 2.2mL of phenyl hydrazine to it. Boil the mixture under reflux for 5minutes and cool the solution whereby tetrahydrocarbazole will crystallize out. Filter at the pump.
Recrystallization: Solvent-aq.ethanol / aq. CH3COOH
M.P: 1170C
Department of Chemistry, RBVRRWC 15 2017-2018
PHTHALIMIDE
Department of Chemistry, RBVRRWC 16 2017-2018
PREPARATION OF PHTHALIMIDE
Aim: To study imide formation.
Principle: Nucleophile is amino group of urea, both amine groups of urea acts as nucleophile, attracts 2 moles of phthalic anhydride resulting in the formation of 2 moles of phthalimide.
Reaction: Nucleophilic Substitution Reaction.
Chemicals: Phthalic anhydride – 2g
Urea – 0.4g.
Apparatus: Round bottomed flask, sand bath.
Procedure: Mix 2gms of phthalic anhydride and 0.4gms of urea and place the mixture in Round bottomed flask. Heat the flask on low flame on sand bath. When the contents melt effervescence commences and gradually increases after 10-20 min, the mixture suddenly froths up to about 3 times the original volume and becomes almost solid. Remove it from the flame and allow it to cool and add 5mL of water to it. Filter at pump.
Recrystallization: Solvent -Methanol
M.P: 2330C
Department of Chemistry, RBVRRWC 17 2017-2018
Department of Chemistry, RBVRRWC 18 2017-2018
Department of Chemistry, RBVRRWC 19 2017-2018
Department of Chemistry, RBVRRWC 20 2017-2018
PREPARATION OF META - DINITRO BENZENE
Aim: To prepare m-dinitro benzene from nitro benzene by nitration
Principle: Nitro group is deactivating group or electron withdrawing group. It is a meta directing group and hence it requires drastic conditions when compared to nitration of benzene.
Reaction: Electrophilic Substitution Reaction
Chemicals:Nitrobenzene – 2mL
Fuming HNO3 – 2.5 mL
Conc.H2SO4- 3.5mL
Apparatus: Round bottomed flask,Conical flask & Beaker.
Procedure: Measure about 2 mL of nitrobenzene in 250mL R.B. flask, then separately prepare the nitration mixture in conical flask by measuring 2.5mL of fuming nitric acid andadd3.5mL of conc.
H2SO4dropwise by cooling in ice bath. The addition of conc.
H2SO4to fuming HNO3 should be completed within 5-10 min.Add this mixture drop wise to nitrobenzene and shake nearly for 10min. Fix the water condenser and reflux for 1 hourin hot water bath. Shake the flask and pour these contents into cold water taken in a beaker. A pale yellow m-dinitrobenzene is formed and is filtered.
Recrystallization: Solvent- Alcohol
M.P: 890C
Department of Chemistry, RBVRRWC 21 2017-2018
Department of Chemistry, RBVRRWC 22 2017-2018
PREPARATION OF META – NITRO ANILINE
Aim: To study selective reduction.
Principle: The nitro group is an electron withdrawing group. In meta dinitro benzene, the two nitro groups withdraws electrons from benzene and is destabilized due to accumulation of positive charge on the
ring. In the presence of reducing agents like Na2S2, the nitro group in the meta position is reduced to amino group. Since amino group is electron releasing group, it stabilizes the ring by allowing the charge dispersal.
Reaction : Partial Reduction / Semi Reduction
Chemicals: Meta-dinitro benzene - 5gms Conc. HCl- 9mL Aqueous NH3 Sodium sulphide – 7gms Sulphur – 1.5gms
Apparatus: Beaker, glass rod
Procedure: Add 1.5g of finely powdered sulphur to a solution of 7g of Na2S in
40mL of H2O in a beaker and boil the mixture gently for few minutes until a clear solution of bisulphide is obtained. Heat 5g of m-dinitro benzene in 50mL of water and add bisulphide solution dropwise for 40 min. Stir the solution with glass rod. Boil the solution gently for 20 min. Allow it to cool in ice, filter it and wash with cold water. Transfer the solid to a beaker containing 40mL of water and add 9mL of conc. HCl, boil for 15 minutes. Meta nitro aniline dissolves leaving sulphur and other unreacted m-dinitro
benzene. Filter it and add excess of aq. NH3 to the filtrate (liquid). Meta nitro aniline separates as bright yellow crystalline compound.
Recrystallization: Solvent-Alcohol
M.P:1140C
Department of Chemistry, RBVRRWC 23 2017-2018
ANTHRACENE MALEIC ANHYDRIDE ADDUCT
O General Reaction O O O
O
O Anthracene Maleic anhydride Diels Alder adduct 9, 10 dihydro Anthracene-9,10 end--succinic anhydride
Mechanism O O O O
O
O
Department of Chemistry, RBVRRWC 24 2017-2018
PREPARATION OF ANTHRACENE MALEIC ANHYDRIDE ADDUCT
Aim: To study the Diels – Alder Reaction.
Principle: Addition of conjugated Diene and Dienophile is known as Diels Alder Reaction. Compounds containing a double or triple bond, activated by suitable adjacent groups add to the 1,4 – positions of a conjugated system with the formation of a six membered ring.
Reaction : Diels – Alder Reaction.
Chemicals: Anthracene – 2gm
Maleic anhydride – 1gm
Dry xylene – 13mL
Charcoal
Apparatus: R. B. flask, water condenser & funnel.
Procedure: In a small Round bottomed flask, place 2gm of pure anthracene, 1g of maleic anhydride and add 13mL of dry xylene. Boil the mixture under the reflux for 20 mins with frequent shaking during the first 10 min. Allow the mixture to cool for 15 min and add a pinch of charcoal and continue boiling for another 5 min. Filter the hot solution. Crystals will get separated.
Recrystallization: Solvent - Xylene
M.P: 2560C -2580C
Department of Chemistry, RBVRRWC 25 2017-2018
2,4- DIHYDROXY RESACETOPHENONE 2,4 – DIHYDROXY ACETOPHENONE General Reaction
HO OH O HO OH ZnCl2 OH
O 2,2,44- D– iDihydroxyhydroxy R eAcetophenonesacetophenon e Mechanism
O O ZnCl2 ZnCl2OH OH
HO OH HO OH
H H
HO OH O HO OH
H - H H O HO OH
2,4 – DihydroxyAcetophenoneO 2,4- Dihydroxy Resacetophenone
H ZnCl2OH ZnCl2 H2O
Department of Chemistry, RBVRRWC 26 2017-2018
PREPARATION OF 2, 4 – DIHYDROXY ACETOPHENONE
Aim: To study Nenki Reaction.
Principle: Resorcinol reacts with acetic acid in the presence of Zinc chloride to give acetophenone
Reaction: Nenki Reaction.
Chemicals: Resorcinol – 5g
Acetic acid – 10mL
Anhydrous ZnCl2- 5gms.
Apparatus: 500mL beaker, sand bath and thermometer.
Procedure: Dissolve anhydrous ZnCl2in acetic acid taken in 500mL beaker. Add resorcinol in small quantities slowly while heating on a sand bath at 800C. After addition is completed heat the mixture slowly at 1100C and rapidly to 1400C for 15 minutes. Cool this mixture and pour it into 1:1 HCl and water. Yellow product separates out.
Recrystallization: Solvent-Boiling water
M.P: 1420C
Department of Chemistry, RBVRRWC 27 2017-2018
7-HYDROXY-4-METHYL-COUMARIN (UMBELLIFERRONE)
General Reaction
HO OH O O HO O O H2SO4 O ethyl aceto acetate
7-Hydroxy-4-methyl coumarin
Mechanism EtO O O HO OH HO OH O O
H O
EtO EtO HO OH O HO OH O
H2O
H OH
H HO O O HO O O
OEt C2H5OH
7-Hydroxy-4-methyl coumarin
Department of Chemistry, RBVRRWC 28 2017-2018
PREPARATION OF 7- HYDROXY– 4 – METHYL COUMARIN
(UMBELLIFERRONE)
Aim: To study Pechmann reaction.
Principle: Ethyl aceto acetate in acidic medium exists, as in enolic form, this will condense with resorcinol, undergoes cyclisation to yield 7- hydroxy - 4 -methyl Coumarin.
Reaction: Condensation Reaction.
Chemicals: Resorcinol – 1 gm
Ethylaceto acetate – 4.4mL
Conc. H2SO4- 4mL Apparatus: Beaker &Conical flask.
Procedure: Measure 4mL of conc. H2SO4 into 150mL beaker and cool in ice water until temp reaches 50C. Take 1g of powdered resorcinol into a clean conical flask, to this add 4.4mL of ethyl aceto acetate and stir well, until a clear solution is obtained. Now add this mixture 0 slowly into H2SO4 by maintaining the temperature between 5-10 C and continue stirring for half an hour and pour the solution into fresh ice, where by solid of 7-hydroxy–4–methyl coumarin separates out. Filter the compound under suction.
Recrystallization: Solvent- Ethanol / Methylated spirit
M.P: 1850C
Department of Chemistry, RBVRRWC 29 2017-2018
Department of Chemistry, RBVRRWC 30 2017-2018
PREPARATION OF AZALACTONE
Aim: To study Earlein-Mayer Azalactone Synthesis
Principle: Acyl derivative of glycine condenses with aldehyde followed by cyclisation. Benzaldehyde reacts with active methyl group in the presence of acetic anhydride. This reaction is called as Earlein- Mayer Azalactone Synthesis
Reaction: Condensation.
Chemicals: Benzaldehyde – 3mL
Hippuric acid – 4.5g
Sodium acetate
Acetic anhydride – 7.5mL.
Apparatus:Round bottomed flask &Measuring jar.
Procedure: Place a mixture of 3mL pre-distilled benzaldehyde,4.5gms of hippuric acid, 7.5mL of acetic anhydride and freshly prepared sodium acetate in a round bottomed flask and heat on electric hot plate with shaking, as soon as the mixture turns to liquid completely, transfer the flask to a water bath, fix the condenser and heat for an hour and add 10mL of alcohol. Allow the mixture to stand for 15 minutes and filter it.
Recrystallization: Solvent - Hot water / Alcohol
M.P: 1670C
Department of Chemistry, RBVRRWC 31 2017-2018
Department of Chemistry, RBVRRWC 32 2017-2018
MULTI - STEP SYNTHESIS OF ORGANIC COMPOUNDS
Department of Chemistry, RBVRRWC 33 2017-2018
Department of Chemistry, RBVRRWC 34 2017-2018
CONTENTS
1. 2-PHENYL INDOLE
2. 7-HYDROXY-3-METHYL FLAVONE
3. 2,5-DIHYDROXY ACETOPHENONE
4. BENZILIC ACID
5. BENZPINACOL
6. 7-HYDROXY COUMARIN
7. PHOTODIMERIZATION OF MALEIC ANHYDRIDE
8. BENZOPHENONE
9. 4-CHLORO TOULENE
10. BENZANILIDE
11. VANILLYL ALCOHOL
12. O & P-NITRO PHENOLS
13. ACRIDONE
Department of Chemistry, RBVRRWC 35 2017-2018
Department of Chemistry, RBVRRWC 36 2017-2018
2 – PHENYL INDOLE
Aim: To synthesise 2-phenyl indole.
Chemical Name: 2 – phenyl indole
Principle: Synthesis of 2- phenyl indole involves two steps. Step 1: Formation of Schiff’s base by the reaction between acetophenone and phenyl hydrazine. Step 2: Cyclisation of the phenyl hydrazine derivative in presence of polyphosphoric acid to form 2-phenyl indole.
Type of Reaction: Fischer Indole synthesis
Step 1: Preparation of Acetophenone phenyl hydrazine
Chemicals:Acetophenone -2.5mL Phenyl hydrazine - 3mL Rectified spirit- 5mL Apparatus required: R.B. flask & water condenser. Procedure: Warm a mixture of 2.5mL acetophenone, 3mL of phenyl hydrazine and 4mL of glacial acetic acid on a water bath for 1 hr. Dissolve the hot mixture in 5mL of rectified spirit and shake. Stir to induce crystallization. Cool the mixture in ice, filter and wash with 1.2mL of rectified spirit. Dry in vacuum desiccator over anhydrous calcium chloride for at least half an hour. Yield: 1.5gms. M.P: 1050C
Step 2: Preparation of 2-phenyl indole Chemicals: Acetophenone phenyl hydrazone -1.5gm Phosphoric acid-8mL Phosphorus pentoxide-3gm Procedure: Add 1.5gm of acetophenone phenyl hydrazone to pre heated (800C) 10gm of polyphosphoric acid (8mL of phosphoric acid, 3gm of phosphorus pentoxide is added and heated if necessary to get a clear solution the solution is poly phosphoric acid). Stir the mixture at 1000 C for 1hour on water bath. Cool the solution, stir in ice water and filter off the grey precipitate. Wash the residue with cold water and dry at 1000C. Recrystallisation: Solvent – ethanol Yield: 1 gm M.P: 1850C
Department of Chemistry, RBVRRWC 37 2017-2018
K2 7-Hydroxy-3-methyl Flavone
Step-1 2,4- dihydroxy Propiophenone
HO OH O HO OH ZnCl2 OH 140oC Resorcinol Propionic acid Respropiophenone O Mechanism O O
ZnCl2 ZnCl2OH OH
HO OH HO OH HO OH O H H O O
H ZnCl2OH ZnCl2 H2O
Step-2 HO OH O
Ph Cl + K2CO3 Benzoyl chloride O
HO O Ph
O 7-Hydroxy-3-methyl Flavone
Department of Chemistry, RBVRRWC 38 2017-2018
7-HYDROXY-3-METHYL FLAVONE
Aim:To synthesize 7-Hydroxy 3-methyl Flavone by Baker Venkatraman method.
Chemical Name: 7-Hydroxy 3-methyl Flavone
Principle: Respropiophenone reacts with benzoyl chloride and the product on condensation and cyclisation gives flavones.
Type of Reaction: Condensation
Step 1: Preparation of Respropiophenone:
Chemicals: Acetone-60mL Resorcinol-11gms, Anhydrous ZnCl2 - 10gms, Propionic acid-7.4mL.
Apparatus required: R.B flask & Reflux condenser
Procedure: 11gms of Resorcinol was added slowly to a mixture of anhydrous ZnCl2 and propionic acid taken in 500mL beaker while heating on a sand bath at 800C. After the addition is completed, heat the mixture slowly to1100C and rapidly to 1400C for 45 min. Cool the red viscous mass obtained to room temperature and stirred in ice cold water. The orange red solid respropiophenone is filtered and dried.
Recrystallisation: Solvent-boiling water.
Yield: 8gms.
M.P: 1010C
Department of Chemistry, RBVRRWC 39 2017-2018
Department of Chemistry, RBVRRWC 40 2017-2018
Step II: Preparation of 7-Hydroxy 3-methyl Flavone
Chemicals: Respropiophenone-8gms Benzoyl chloride-4.2mL Potassium carbonate 20gms
Apparatus required: R.B flask & Reflux condenser
Procedure: 60mL of acetone and 8gms of Respropiophenone was refluxed with 4.2mL benzoyl chloride and 20gms potassium carbonate for 12 hrs. The solvent was removed, the residue was cooled and treated with 200mL ice-cold water. The reddish brown solution was saturated with CO2 and the product separated by filtration.
Recrystallisation: Solvent- methanol.
Yield: 2.8 gms
M.P: 2780C
Department of Chemistry, RBVRRWC 41 2017-2018
2,5 DIHYDROXY ACETOPHENONE
Step 1
OH OCOCH3
H2SO4 Ac2O
OH OCOCH3 Hydroquinone Hydroquinone diacetate Mechanism ( O -Acylation )
O O O O O O H 2 2 2 2 O O OH H O O O OH H O C CH3 O C CH3
O O
OH H O C CH3 O C CH3 Step 2 Fries Migration
O
O C CH3 OH O
2 AlCl3
O
O C CH3 OH 2, 5 dihydroxy acetophenone
Department of Chemistry, RBVRRWC 42 2017-2018
2, 5-DIHYDROXY ACETOPHENONE
Aim: To study the Fries migration.
Chemical Name: 2,5-dihydroxy phenyl methyl ketone.
Principle: Acylation of phenols gives phenolic esters. Phenolic esters undergo Fries rearrangement in the presence of anhydrous aluminium trichloride to give phenolic ketones.
Step I: Preparation of Hydroquinone diacetate:
Chemicals:Hydroquinone- 5gm Acetic anhydride- 10mL Conc. Sulphuric acid- 2 or 3 drops
Apparatus required: R.B flask – 250mL.
Procedure: In a R.B flask 5gm of hydroquinone, 10mL acetic anhydride, 2-3 drops of conc. sulphuric acid are taken and the flask is gently shaken for 15 min. The contents of the flask are poured into 100gm of crushed ice with stirring. Filter the product obtained, wash with little ice-cold water.
Recrystallisation: Solvent-ethanol.
Yield: 6gms.
M.P: 1220C
Department of Chemistry, RBVRRWC 43 2017-2018
Mechanism
O O
O C CH3 Cl Al O Cl3Al O C CH3 3 O AlCl3 2 C CH3 O O
O C CH3 Cl Al O Cl3Al O C CH3 3
OH O Cl3Al O O Cl3Al O O H CH 3 2 H CH3 - H CH3
OH Cl Al O Cl Al O 2, 5 dihydroxy 3 3 acetophenone
Department of Chemistry, RBVRRWC 44 2017-2018
Step II: Preparation of 2.5 dihydroxyacetophenone:
Chemicals:Hydroquinone diacetate - 4gm, Anhydrous aluminumtrichloride - 10gm Conc. HCl- 3mL.
Apparatus required: R.B flask, air condenser & oil bath.
Procedure: In a 250mL Round bottomed flask, 4gm of hydroquinone diacetate, 10 gms anhydrous aluminium trichloride are added and is fixed with an air condenser. Heat the contents for half an hour on oil bath or on low flame maintaining the temp in between 115 -1200C. When the evolution of gas started, raise the temperature to 165 -1700C and continue heating for about 30min. Now cool the contents by adding crushed ice and 3.5mL conc. HCl. Filter the product and wash with ice-cold water.
Recrystallisation: Solvent- rectified spirit.
Yield: 3.6 gms.
M.P: 2030C
.
Department of Chemistry, RBVRRWC 45 2017-2018
4-CHLORO TOULENE General Reaction Cl NH2 N2Cl
NaNO2 0oC, HCl
CH CH3 CH3 3 p-toulidine 4-methyl benzene p-chloro Toulene diazonium chloride Mechanism Step 1 Formation of Diazonium ion
NaNO2 HCl HO N O NaCl
NO HO N O H H2O N O
H C NH 3 2 NO H3C N N O H H
H H C N N O H3C N N O H 3 H H
H H C N N OH 3 H3C N N OH2 - H2O
Cl H C N N H3C N N 3
H C N N Cl 3 OR H3C N N Cl
4-methyl benzene diazoinium chloride
Department of Chemistry, RBVRRWC 46 2017-2018
4-CHLORO TOULENE
Aim: To study the Sandmayer reaction.
Chemical Name: 4-methyl chloro benzene.
Principle: Primary aromatic amines can be converted into diazonium salts which when treated with cuprous chloride produces chloro aromatic compounds.
Chemicals required: Para toulidine- 1.5gms ConcHCl- 4mL Sodium nitrite-1gm Cuprous chloride CuSO4 NaCl
Procedure:
STEP 1: Dissolve 3.6 gms of p-toulidine in 8.5mL of conc HCl and 8.5mL of H2O in a conical flask. Cool the mixture to 0oC in an ice salt bath with vigorous stirring with addition of little crushed ice. The p-toulidine HCl salt will separate as a crystalline precipitate.
STEP 2: Dissolve 2.4 gms of NaNO2 in 5mL of H2O and add this solution drop wise to p-toulidine solution stir well and keep at 0-5oC by addition of little crushed ice from time to time. A solution of diazonium salt is formed.
STEP 3: Preparation of Cu(1) chloride solution: Dissolve 3.5gms of CuSO4.5H2O &1.5gms of pure NaCl in 12.5mL of H2O. Heat the solution to boiling with low flame using wire gauge. Add 8mL of conc. HCl and 2gms of Cu turning and continue heating and reflux until the solution inside the Round bottomed flask becomes colourless. Cool in ice to 0-5oC
Department of Chemistry, RBVRRWC 47 2017-2018
Step 2 Sandmayer Reaction
Cu Cu+2 H3C N N Cl H3C N2
Cu+2 +1 H3C H3C Cu
Cl
H3C Cl
4-chloro toulene
Department of Chemistry, RBVRRWC 48 2017-2018
STEP 4:
Pour the cold diazonium chloride solution slowly with shaking into cold Cu(1) chloride solution. Sandmayer reaction proceeds rapidly with frothing. The mixture becomes viscous and it is allowed to cool to room temperature while shaking. The p- chlorotoulene separate as an oily layer. The reaction mixture is steam distilled until no more oily drops are present in the distillation. The p- chlorotoulene oily product is separated and washed with NaOH solution and dried on CaCl2.
Recrystallisation: By distillation
Yield: 10.6 gms.
M.P: 1600C
Department of Chemistry, RBVRRWC 49 2017-2018
Department of Chemistry, RBVRRWC 50 2017-2018
BENZILIC ACID Aim: To study benzilic acid rearrangement. Chemical Name:2, 2-diphenyl, 2-hydroxy ethanoic acid. Principle: Benzoin undergoes oxidation in presence of conc. nitric acid to give benzil. Benzil in presence of KOH undergoes rearrangement to give benzilic acid. Type of Reaction: Benzilic acid rearrangement. Step 1: Benzoin condensation:
Chemicals: Benzoin 2gm, conc HNO3-5mL Apparatus required: 250mL R.B flask &reflux water condenser
Procedure: Place 2gm of powdered benzoin and 5mL of conc HNO3 in a 250mL R.B flask fitted with a water condenser and reflux on a boiling water bath. Continue heating for 1 hour when the crystalline benzoin will have been completely replaced by oily benzil. Then pour the mixture into a beaker of cold water. On vigorous stirring, the oil will crystallize into a yellow solid. Filter off the latter at the pump and wash thoroughly with water to ensure complete elimination of water. Recrystallisation: Solvent-rectified spirit. Yield: 1.5gms. M.P: 950C Step II: Benzilic acid rearrangement: Chemicals: KOH pellets-1gm, rectified spirit or ethanol-3mL recrystallised benzil-1gm, conc. HCl-2-3 drops Apparatus required: 250mL R.B. Flask & water bath. Procedure: In a 250mL conical flask place a solution of 1gm of KOH pellets in 2mL of water and then add 3mL of ethanol and 1gm of recrystallised benzil. A deep bluish black solution is produced. Cork the flask and boil the mixture on water bath for 10-15min. Pour the contents of the flask in a porcelain dish and cool in ice water. A potassium salt of benzilic acid crystallizes out. Filter at pump and wash with ice-cold ethanol. Dissolve the potassium salt in about 10mL water and add slowly with stirring 2-3drops of conc. HCl. The precipitate thus produced is colored red-brown and sticky. Filter this off. The filtrate should be nearly colorless. Continue the addition of HCl with stirring until the solution is acidic to litmus paper. Filter off benzilic acid under suction, wash with cold water. Recrystallisation:Solvent- hot benzene / hot water with charcoal Yield: 0.9 gms M.P: 1500C
Department of Chemistry, RBVRRWC 51 2017-2018
Department of Chemistry, RBVRRWC 52 2017-2018
BENZPINACOL (PHOTOREDUCTION)
Aim: Photoreduction of Benzpinacol.
Chemical Name: 1, 1, 2, 2-tetra phenyl 1, 2-ethane diol.
Principle: Photochemical reaction.
Type of Reaction:Photoreduction.
Chemicals: Benzophenone-2gms, Isopropyl alcohol-8mL, glacial acetic acid.
Apparatus required: 100mL R.B flask, 100mL beaker & Buchner funnel.
Procedure: Place 2gms of benzophenone in a 100mL R.B flask and dissolve in 8mL of isopropyl alcohol by warming. Fill the flask up to the neck with more alcohol and added a drop of glacial acetic acid and stopper the flask tightly. Invert the flask in a 100mL beaker and expose to bright sunlight. The formation of benzpinacol can be followed by the appearance of colourless crystals around the walls of the flask, as the product is sparingly soluble in isopropyl alcohol, 95% of the reaction is completed in 3-4 days. Take out the flask and filter the crystals in the Buchner funnel. The product is 100% pure.
Recrystallisation: not necessary.
Yield: 1.5gms.
M.P: 1850C
Department of Chemistry, RBVRRWC 53 2017-2018
Department of Chemistry, RBVRRWC 54 2017-2018
7 – HYDROXY COUMARIN
Aim: To prepare 7- Hydroxy Coumarin by Pechmann synthesis
Chemical Name: 7- Hydroxy Coumarin
Principle: Condensation reaction of resorcinol with malic acid in the presence of sulphuric acid involve the loss of one carbon atom as carbon monoxide to give 7-hydroxy coumarin.
Type of Reaction: Electrophilic substitution & Condensation.
Chemicals required:Resorcinol- 2gm Malic acid – 2.5gms
Apparatus: 250mL conical flask, beaker &thermometer.
Procedure: In 250 mL conical flask add 2gms of m-dihydroxy benzene, 2.5gms of malic acid and 5mL of conc. H2SO4 (carefully). The flask is held with a clamp, and is gently swirled by hand over the yellow flame of a Bunsen burner in hood. The heating is continued until the mixture begins to foam. By cautious heating maintain the foaming for several minutes. Let it cool in the air for about 5mins and with good swirling pour into about 100mL of water containing some ice. Use little more water as a rinse. The cold suspension is suction filtered. The damp precipitate is given a charcoal treatment in warm ethanol and the hot filtered ethanolic solution is ice cooled. The 7- hydroxyl coumarin is obtained as pale pink prisms.
Recrystallisation: Solvent - ethanol.
Yield: 2gms.
M.P: 2270C
Department of Chemistry, RBVRRWC 55 2017-2018
Department of Chemistry, RBVRRWC 56 2017-2018
PHOTODIMERISATION OF MALEIC ANHYDRIDE
Aim: To carry out photodimerisation reaction using maleic anhydride.
Chemical Name:1,2,3,4- Tetracarbomethoxy cyclobutane
Principle: Photodimerisation of maleic anhydride in presence of sunlight
Type of Reaction:2+2 cycloaddition.
Chemicals:Maleic anhydride crystals CCl4- 150-160mL
Apparatus:Conical flask 250mL
Procedure:1gm of finely divided crystals of Maleic anhydride, of melting point close to 54 degrees is taken in 150-160mL of CCl4 is warmed on a steam bath in a 250mL conical flask (until the mixture is warm to the hand). This flask is corked and put in a window where sunlight will fall on it for few hours each day, 5-6 hrs of exposure to sunlight is advisable for a good yield. A fine suspended solid is obtained which is gravity filtered and air-dried.The product is taken in a small R.B flask, 20-25mL of methanol and a drop of conc. sulphuric acid are added and suspension is warmed on steam bath. Reflux for at least for half an hour, the condenser is removed and methanol is boiled off to about half its volume, crystals begin to separate. Cooling in the water and suction filtration (with a Hirsch funnel) is followed; precipitate is washed with little cold methanol. The crystals of tetra methyl ester are spread out on a watch glass to dry for a few minutes. Melting point is then determined.
Recrystallisation: Solvent- chloroform.
Yield: 12.5gms.
M.P: 540C
Department of Chemistry, RBVRRWC 57 2017-2018
Department of Chemistry, RBVRRWC 58 2017-2018
BENZOPHENONE
Aim: To study Friedel Crafts acylation reaction.
Chemical Name:Benzophenone
Principle:Aromatic acylation reaction in presence of AlCl3
Chemicals: Finely powdered AlCl3 - 1gm Benzene - 1.5mL Benzoyl chloride – 1gm Carbonbisulphite-3mL
Apparatus:R.B flask, reflux condenser, test-tube.
Procedure:Freshly prepared finely powdered AlCl3 weighed into a dry corked test tube. It is poured with frequent shaking during the course of 10 min into a dry R.B flask containing 1.5mL of benzene, 1gm of benzoyl chloride and 3mL of pure CS2. The flask is then attached to a long reflux condenser and warmed on the water bath at 500C until only small amounts of HCl are being evolved (2- 3 hrs). The solution acquires a deep brown colour. The CS2 (or benzene) is now removed by distillation through a down ward condenser and the residue is cautiously poured, while still warm into a capacious flask containing about 10cc of water & small pieces of ice. After rinsing out the reaction flask with a little water and adding 10 cc of conc. HCl to the reaction mixture, steam is passed then for about 20min. The material remains in the flask is then cooled, taken up in ether and shaken several times with dilute sodium hydroxide solution. After the ethereal solution has been dried with CaCl2 and the ether has been evaporated, the residue is distilled from a flask with low side tube. A pure product is obtained by vacuum distillation in a sausage flask.
Recrystallisation: Solvent-Alcohol
Yield: 1gms.
M.P: 480C
Department of Chemistry, RBVRRWC 59 2017-2018
Department of Chemistry, RBVRRWC 60 2017-2018
BENZANILIDE Aim: To study Beckmann rearrangement. Chemical Name:N-phenyl benzamide Principle: Benzophenone condenses with hydroxylamine hydrochloride in presence of excess of NaOH solution to yield benzophenone oxime. By treatment of this oxime with PCl5 or SOCl2 in ether solution, conversion results into benzanilide. The change of any oxime into a substituted amide under the conditions mentioned is termed as Beckmann rearrangement. Type of Reaction: Beckmann rearrangement Step 1: Preparation of benzophenone oxime: Chemicals:Pure benzophenone - 2.5gms, hydroxylamine hydrochloride - 1.5gms, rectified spirit- 5mL, water, NaOH pellets-2.8gms, conc HCl- 7.5mL. Apparatus:50mL R.B flask, reflux condenser, 250mL beaker. Procedure:A mixture of 2.5gms of pure benzophenone, 1.5gms hydroxylamine hydrochloride, 5mL rectified spirit and 1mL of water in a 50mL R.B flask. Add 2.8gms NaOH pellets in portions with shaking. If the reactions become too vigorous, cool the flask under running tap water. When all the NaOH has been added attach a reflux condenser, heat to boiling and reflux for 5 min. Cool and pour the contents of the flask into 7.5mL of conc. HCl& 5mL of water taken into a 250mL beaker. Filter off the precipitate at the pump, was thoroughly with cold water and drain well. Recrystallisation:Solvent-methanol. Yield: 2.7gms M.P:1420C Step II: Preparation of Benzanilide from benzophenoneoxime:
Chemicals:Benzophenone oxime-2gms, anhydrous ether-20mL, SOCl2- 3mL, H2O- 25mL Apparatus:100mL conical flask &water bath Procedure:Dissolve 2gms of benzophenone oxime in 20mL of anhydrous ether in 100mL conical flask and add 3mL of thionyl chloride. Distill off the solvent and other volatile products on a water bath (Caution ether). Add 25mL of water. Boil for several minutes and break up any lumps which may be formed. Decant the supernatant liquid. Recrystallisation:Solvent-boiling alcohol. Yield: 2 gms M.P:1630C
Department of Chemistry, RBVRRWC 61 2017-2018
Department of Chemistry, RBVRRWC 62 2017-2018
VANILLYL ALCOHOL
Aim: To study the reduction using sodium borohydride.
Chemical Name: 4-hydroxy-3-methoxy phenyl methanol.
Principle: NaBH4 as a reducing agent is used to reduce the carbonyl compounds. Salient feature of this reagent is its selective reduction of carbonyl compounds even in the presence of other reducible groups. During acidification unused NaBH4 rapidly reacts with the protons to liberate H2 gas. Since the product is slightly insoluble in acid solution, the solid separates in the acidic solution.
Type of Reaction: Reduction of aldehyde.
Chemicals: Vanillin-1gm, 1N NaOH-7.2mL, NaBH4 - 0.13gms, Conc. HCl- 0.6mL, ethyl acetate
Apparatus: 250mL conical flask, ice water bath, measuring jar &glass rod.
Procedure:In 250mL conical flask add 1gm of vanillin and 7.2mL of 1N NaOH. The flask is cooled to about 10-15 degrees by swirling it in an ice water bath for a minute. 0.13gms ofNaBH4 is added in portions over a period of 5min with good swirling. The flask is allowed to stand for half an hour, thenput back in the cooling bath and the solution of 0.6mL of conc HCl mixed with 2.5mL of water is added in 2-3mL portions with steady swirling. There is a lively evolution of hydrogen. HCl is added until litmus test indicates that the solution is weakly acidic. Since the product has a remarkable tendency to super saturate it may not separate until it is gently scratched with a glass rod. Cool well and suction filter.
Recrystallisation: Solvent-Ethyl acetate.
Yield: 0.8grm
M.P:1150 C
Department of Chemistry, RBVRRWC 63 2017-2018
Ortho And para nitro phenols
General Reaction
OH OH OH
NO2
HNO3
o-nitro phenol NO2 p-nitro phenol
Mechanism
H NO + - 2 HNO3 2 3 NO3
+ + H2NO3 NO2 H2O
OH OH OH
NO2
H NO NO 2 2 p-nitro phenol
OH OH H OH NO 2 NO2 NO2
o-nitro phenol
Department of Chemistry, RBVRRWC 64 2017-2018
ORTHO AND PARA NITRO PHENOLS
Aim: To prepare ortho and para nitro phenols.
Chemical Name: 2-Nitrophenol and 4-Nitro phenol
Principle: Hydroxy group in phenol is ortho para directing. Nitration of phenol gives ortho and para nitro phenol mixture. Separation of the mixture is done by steam distillation. Ortho nitro phenol having intra molecular hydrogen bonding is steam volatile comes out first, p-nitro phenol is having inter molecular hydrogen bonding remains in the solution.
Type of Reaction:Aromatic Electrophilic Substitution
Chemicals:Conc HNO3 -12 mL, phenol-8.8mL
Apparatus:R.B flask &water condenser.
Procedure:Measure out 12 mL of Conc. Nitric acid in a beaker and add 40ml of water. Take 8.8mL of molten phenol in a small test tube and 2-3mL of water and add 2mL of phenol to the acid. The immediate reaction is marked by the appearance of a dark colouration in the solution and by the evolution of heat. Cool the solution if necessary to keep the temperature below 600C and add small portions of phenol and cool every time to maintain the temperature as nearly as possible at 450C-550C range. After the introduction of phenol (which requires about 5 minutes),cool the flask until the temperature of mixture is 250 C to 300 C and pour the contents of the beaker into a small separating funnel. Withdraw the lower oily layer into a round bottomed flask for steam distillation. Discard the upper layer. The heavy oily layer consists of chiefly ortho and paro nitro phenols and some oxidation products of indefinite composition. It is subjected to distillation in steam until all the o-nitro phenol has been carried over to the receiver. This will require collection of about 200mL of distillate. If the o-nitro phenol does not solidify in the receiver add a little ice then the o-nitro phenol separates out.
Recrystallisation: Purification by steam distillation.
Yield: 0.50 gms (O-Nitro phenol)M.P: 460 C (O-Nitro phenol)
Department of Chemistry, RBVRRWC 65 2017-2018
Department of Chemistry, RBVRRWC 66 2017-2018
p-nitro phenol: From the above mixture
Procedure:
The p-nitro phenol almost non-volatile and steam remains into the distillation flask partly in solution in hot water and partly as dark coloured oil. Add water to the distillation flask to bring the total volume of liquid to 200mL or if the volume of the liquid greater than 250mL. Heat the flask with a Bunsen burner to remove water by distillation until the contents of the flask do not exceed 250mL in volume. Heat the liquid to the boiling point and filter through a fluted filter paper to the hot filtrate add 2gm of decolourising carbon. Again heat to boiling and filter to remove the carbon. Place empty 400mL beaker into ice bath and add to it 2mL of hot solution. Stir the chilled solution with a glass rod and then occur crystallization of p-nitro phenol. Such rapid cooling brings about crystallization of p-nitro phenol and thus avoids the separation of material as dark oil which usually occurs of allowed to cool slowly.
When crystallization of first small portion of the p-nitro phenol has been attained, add another 2-5mL portion of hot solution and stir briskly a continue adding small quantities of the hot solution to the chilled beaker till entire quantity of the solution has been used collect the crystals of p-nitrophenol on the Buchner funnel and dry them in an oven at about 600C. Recrystallize from hot C6H6.
Yield: 35 gms
M.P: 1120C
Department of Chemistry, RBVRRWC 67 2017-2018
Department of Chemistry, RBVRRWC 68 2017-2018
Department of Chemistry, RBVRRWC 69 2017-2018
Department of Chemistry, RBVRRWC 70 2017-2018
ACRIDONE
Aim: To study multistep synthesis of heterocyclic system
Chemical Name:10H-acridin-9-one
Step I: Preparation of phthalimide:
Principle: 2 moles of phthalic anhydride reacts with 1 mole of urea to give rise to phthalimide with expulsion of CO2 and H2O. Evolution of CO2 can be observed by froathing in the R.B flask.
Type of Reaction:Nucleophilic Substitution Reaction
Chemicals: phthalic anhydride-10gms urea- 2gms
Apparatus:R.B flask & thermometer.
Procedure:Mix 10gms of phthalic anhydride and 2grms of urea and place the mixture in an R.B flask and heat the flask on a low flame at 130-135 degrees when the contents have melted, effervescence commences and gradually increasesafter 10-20 min, the mixture suddenly froths up to about 3 times the original volume (temperature raises to 150-160 degrees) and becomes almost solid. Remove the flame from beneath and allow cooling. Add 2mL of water to disintegrate the solid in the flask and filter at the pump. Wash with little water and dry.
Recrystallisation:Solvent- Alcohol.
Yield: 10gms.
M.P:2330C
Department of Chemistry, RBVRRWC 71 2017-2018
Department of Chemistry, RBVRRWC 72 2017-2018
Step II: Preparation of anthranilic acid from phthalimide:
Principle: Phthalimide undergoes Hoffman rearrangement in the presence of Bromine and sodium hydroxide to give anthranilic acid.
Type of Reaction: Hoffman Rearrangement
Chemicals: I. NaOH-10gms, water - 40mL, bromine-1.7mL II. NaOH- 6gms, water- 24mL, phthalimide- 5gms.
Apparatus required: 250 mL conical flask & thermometer.
Procedure: Prepare a solution of 6gms of NaOH in 24mL of water in 250 mL conical flask and cool to 0 degrees or below in an ice bath and add 1.7mL of bromine in one portion and shake until all bromine reacts, cool again to 0 degrees or below.Prepare a solution of 4gms of NaOH in 16mL of water, add 5gms of finely powdered phthalimide in one portion to the cold solution of sodium hypo bromite and stir vigorously, while swirling the contents of the flask and add the prepared NaOH rapidly. The solution will dissolve and the temperature raises to about 700C, warm the mixture to about 800C for 2 min. Filter if necessary. Cool in ice and add conc. HCl slowly with stirring until the solution is just neutral. (About 30mL). Precipitate the anthranilic acid completely by gradual addition of 20-25mL glacial acetic acid. It is advisable to transfer to 1 lit beaker as some foaming occurs. Filter off the acid at the pump. Wash with little cold water& also with addition of little decolorizing carbon. Collect the acid in Buchner funnel and dry at 1000C.
Recrystallisation: Alcohol
Yield: 8 gms M.P:1450C
Step III: Preparation of orthochloro benzoic acid from anthranilic acid:
Chemicals:I. Anthranilic acid-3.5gms, conc. HCl-5mL, water-25mL. II. sodium nitrite-2gms, water-6mL. III.copper sulphate-6.5gms, NaCl-3gms, water-2.5mL, conc. HCl-20mL, copper turnings-3.5gms. Apparatus: Conical flask &R.B. flask.
Department of Chemistry, RBVRRWC 73 2017-2018
Department of Chemistry, RBVRRWC 74 2017-2018
Procedure: Take mixture of 3.5gms of anthranilic acid, 5mL conc. HCl, 25mL water in a conical flask and heat gently until it dissolves. Cool the solution to about 0-4 degrees in ice bath and diazotize it by adding drop wise, an ice-cold solution of sodium nitrite keeping the temp of the resulting solution below 5 degrees. Take a solution of 6.5gms of copper sulphate, 3gms of NaCl, 2.5mL water in a R.B flask equipped with reflux condenser heat the solution to boiling and add 20mL conc. HCl&3.5gms copper turnings into it and continue boiling until the solution becomes practically colourless. Cool the solution to 0-5 degrees in an ice bath and add to it in portions with constant stirring thecold diazonium salt solution the reaction proceeds rapidly with frothing. After the addition is completed, allow the reaction mixture to stand at room temperature for 1 or 2 hrs with occasional shaking. Filter the product with the Buchner funnel& wash with cold water.
Recrystallisation:Solvent-Water containing a little alcohol
M.P:1380 C
Step IV: Preparation of N-Phenyl anthranilic acid from O-Chloro benzoic acid:
Chemicals: 4gms of orthochloro benzoic acid, 15mL of aniline, 5gms of anhydrous K2CO3 and 1/4gm of CuO.
Apparatus: R.B flask, air condenser &oil bath. Procedure: In a Round-bottomed flask with an air condenser place a mixture of 4gms of orthochloro benzoic acid, 15mL of aniline, 5gms of anhydrous K2CO3 and 1/4gm of CuO. Reflux the mixture for about 2hrs in an oil bath. Allow it to cool, remove excess of aniline by steam distillation and 4gms of decolorizing carbon to the brown residual solution. The mixture is boiled for 15mins and filter at the pump. Add the filtrate with stirring to a mixture of 6mL of Conc.HCl and 12mL of water and allow to cool. Filter off the precipitate with suction and dry.
Recrystallisation: Solvent-mixture of 5mL acetic acid and 3mL water.
Department of Chemistry, RBVRRWC 75 2017-2018
Department of Chemistry, RBVRRWC 76 2017-2018
Step V: Preparation of Acridone from N-Phenyl anthranilic acid:
Principle:Acridone can be prepared by cyclisation of N-Phenyl anthranilic acid by using sulphuric acid.
Chemicals:N-Phenyl anthranilic acid 4gms Conc.H2SO4
Apparatus: Conical flask &water bath.
Procedure: Prepare a mixture of 4gms of N-Phenyl anthranilic acid and 10mL of conc.H2SO4 in a conical flask and heat the mixture for 1½hrs on a steam bath. Then pour the hot dark solution slowly and continuously into 200mL boiling water in 500mL beaker (allow the acid to run down the side of the beaker to prevent spurting). Then the mixture is boiled for 5 min and filtered while hot through Buckner funnel. The precipitate is washed with boiling water and dried.
Recrystallisation: Solvent- acetic acid using animal charcoal.
M.P:3520C
Department of Chemistry, RBVRRWC 77 2017-2018
Department of Chemistry, RBVRRWC 78 2017-2018
ISOLATION OF NATURAL PRODUCTS
Department of Chemistry, RBVRRWC 79 2017-2018
Department of Chemistry, RBVRRWC 80 2017-2018
CONTENTS
1. PIPERINE FROM BLACK PEPPER
2. CAFFEINE FROM TEA LEAVES
3. CINEOLE FROM EUCALYPTUS LEAVES
4. LYCOPENE FROM TOMATOES
Department of Chemistry, RBVRRWC 81 2017-2018
PIPERINE FROM BLACK PEPPER
Aim: To isolate Piperine from black pepper. Chemical Name: 5-(3, 4-methylenedioxy) phenyl-2,4-pentadienyl piperidamide. Structure:
Category:Flavoring agent and insecticide.
Principle: Piperine is an alkaloid present in black pepper to the extent of 10% by weight and is known to be an amide. Piperine can be extracted or isolated from the black pepper with 95% ethanol. In an ideal case the extraction should be carried out in a Soxhlet apparatus. Chemicals Required: Black pepper, 95% ethanol, 10% KOH Apparatus required: Beaker, Water bath, R.B.Flask, Mortar & pestle, funnel Procedure: Weigh 30gms of black pepper grind it finely and make packet. Insert the packet into the Soxhlet apparatus and fix it to the R.B.Flask containing 300mL of 95% ethanol & reflux for 3hrs. After 3hrs distill of the ethanol and add 30mL of warm ethanolic KOH solution. Stir the warm mixture and filter to remove any insoluble matter, warm the solution on a steam bath and add 15-20mL of H2O. At this stage turbidity appears and yellow needles may separate. Keep this solution till the next lab period and filter the crude piperine. Recrystallisation: Solvent-acetone. Description: Colour is brownish black, has aromatic odor, pungent taste. Chemical Constituents: Pepper contains an alkaloid piperine (5-9%), volatile oil (1-2.5%), pungent resin (6%), Piperidine and starch about 30%. Uses:Fruits are used as aromatic stimulant, cures stomach ache &causes feeling of warmth and also usedas condiment which stimulates taste buds with increase in gastric juice. M.P: 1300
Department of Chemistry, RBVRRWC 82 2017-2018
CAFFEINE FROM TEA LEAVES Aim: To isolate caffeine from tealeaves. Chemical Name: 1, 3, 7-trimethyl Xanthine Structure:
Category:Diuretic, Heart and Nerve stimulant Principle: Caffeine is a xanthine derivate. It is 1,3,7- trimethyl xanthine. Caffeine constitutes 1.5% of tea leaf.It is freely soluble in chloroform, benzene and in water in a ratio of 1:100. On addition of lead acetate solution, tannins get precipitated. Tannins are naturally occurring poly phenols. Requirements: Tea powder, lead acetate, beaker, muslin cloth, glass rod, filter paper, distilled water, CHCl3 Procedure: Boil 20gms tealeaves in 500mL beaker with 250mL waterfor 20min. filter through a Buchner funnel without using the filter paper at the pump to remove tealeaves.To the clear filtrate add 60mL of 10% lead acetate solution to precipitate tannins. Leave the mixture for 2-3 days. The precipitate is filtered through a glass wool plug. The filtrate is concentrated on a sand bath for about 30 minutes. On cooling, the solution is extracted thrice with 25mL portion of chloroform. Combined the extractions and remove the solvent by distillation. The residue obtained is cooled and added with 40mL of petroleum ether,then it is stirred for 5 minutes. Filter the crude caffeine. Chemical constituents: 1. Tea leaves are considered as a rich source of caffeine (1-3%). It also contains theobromine and theophylline in minor quantities. 2. The colour of tealeaves is due to tannic acid 3. Tealeaves contain an enzymatic mixture called theose. Uses:1. Caffeine is used as a central nervous system stimulant, due to its cerebral vasoconstrictor effect. 2. It also acts as a diuretic. 3. Theophylline has both the action but it has also smooth muscle relaxant properties. M.P: 235-237 OC
Department of Chemistry, RBVRRWC 83 2017-2018
CINEOLE FROM EUCALYPTUS LEAVES
Aim: To isolate cineole from eucalyptus oil by steam distillation.
Chemical Name:1,3,3trimethyl 2-Oxa bicyclo [2,2,2 ] octane (eucalyptus contains mixture of cineole, camphene, phellandrene). Structure:
Pharmacological activity: local antiseptic drug.
Principle: Steam distillation is a means of separating organic compounds. It is useful to separate compounds having boiling points below 100oC. Passing steam into a natural product can separate the volatile substances.
Requirement: R. B. Flask, distillation apparatus, steam head, eucalyptus leaves.
Procedure: Cut fresh leaves into small pieces and then transferred into R.B.flask, pass steam through the steam head kept into the eucalyptus leaves present in the R.B.flask, which is connected to the condenser and receiver. Collect the first few mL that is the pure eucalyptus oil, extracted from eucalyptus leaves. Eucalyptus oil is obtained as colourless liquid with pleasant smell.
Biological source: Eucalyptus oil is the volatile oil obtained by the distillation of the fresh leaves of eucalyptus globules and other species of eucalyptus.
Uses: Used in the treatment of cold & cough. It is used as a balm, to relieve pain, astringent, antidiarrheal, flavouring agent. Because of its bacteriostatic property it is used as local antiseptic.
Report: A colourless aromatic pungent liquid of eucalyptus oil is obtained.
B.P: 1760C
Department of Chemistry, RBVRRWC 84 2017-2018
LYCOPENE FROM TOMATOES
Aim: To isolate lycopene from tomatoes.
Chemical Name:(6E,8E,10E,12E,14E,16E,18E,20E,22E,24E,26E)- 2,6,10,14,19,23,27,31-Octamethyldotriaconta 2,6,8,10,12,14,16,18,20,22,24,26,30-tridecaene
Structure:
Principle:Lycopene is a bright red and carotenoid pigment & phytochemical extracted from tomatoes and it is purified by using Column chromatography.
Procedure:Weigh about 10gms of red tomato paste from ripened tomatoes and take in a 250mL of R.B.Flask. Add 25mL of methanol & 30mL of dichloro methane. Heat the mixture under reflux for 5 minutes on steam bath with frequent shaking. Filter the mixture under suction & transfer the filterate to a separating funnel. Wash this mixture containing lycopene with three portions of 150mL each with NaCl solution. Dry organic layer over anhydrous magnesium sulphate. Filter & evaporate the solvent.
Family:Carotenoid family
Uses: It is a powerful antioxidant to prevent heart disease, hardening of the arteries (atherosclerosis) and cancer of the prostate gland, breast, lungs, bladder, ovaries, colon & pancreas.It is also used for treating uterine cancer, cataracts and asthma.
Report:A deep red solid is isolated.
M.P:172–173 °C
Department of Chemistry, RBVRRWC 85 2017-2018
Department of Chemistry, RBVRRWC 86 2017-2018
SYNTHESIS OF DRUGS
Department of Chemistry, RBVRRWC 87 2017-2018
Department of Chemistry, RBVRRWC 88 2017-2018
CONTENTS
1. PHENYTOIN
2. BENZOCAINE
3. 6-METHYL URACIL
4. CHLORBUTOL (CHLORITONE)
5. SULFANILAMIDE
6. FLOURESCEIN
7. ANTIPYRINE
Department of Chemistry, RBVRRWC 89 2017-2018
PHENYTOIN
General Reaction
Ph O O H2N NaOH / EtOH NH O Ph H O Ph O H2N 3 N O Ph H Phenytoin
Mechanism H H OH Ph O H O O N N Ph O Ph H2N O Ph Ph O NH2 N H NH2 O Ph O H
OH OH O H H H N N Ph H Ph NH -H2O O Ph O Ph Ph N N H H Ph N O H OH2 OH
- H
O NH Ph
N O Ph H Phenytoin
Department of Chemistry, RBVRRWC 90 2017-2018
PHENYTOIN
Aim: To synthesize an anticonvulsant drug-phenytoin.
Chemical name: 5, 5-diphenylhydantoin
Pharmacological activity: Anti-convulsant
Principle: It consists of condensation of benzil and urea followed by Pinacol-pinacolone rearrangement in the presence of acid.
Chemicals:Benzil – 2.65 gms Urea – 1.5gm, NaOH – 7.5mL, Ethanol – 37mL
Apparatus required: 100 mL R.B flask & reflux condenser.
Procedure: Place 2.65 gm of benzil, 1.5 gm of urea, 7.5 mL of 30% sodium hydroxide solution and 37mL ethanol in a 100 mL Round bottomed flask, attach a reflux condenser and boil under reflux using electric water bath for 2 hrs. Cool the R.B. flask, pour the reaction product into 100 mL of water and mix thoroughly. Allow it to stand for 15 min. And then filter under suction to remove insoluble bye product. Render the filtrate strongly acidic with conc. HCl. Cool in the water and immediately filter off the precipitated product under suction.
Recrystallisation: Solvent – ethanol.
Yield: 3.5 grms
M.P: 297-2980C
Department of Chemistry, RBVRRWC 91 2017-2018
Department of Chemistry, RBVRRWC 92 2017-2018
BENZOCAINE
Aim: To prepare an anaesthetic drug-benzocaine.
Chemical name: Ethyl-p-amino benzoate
Pharmacological activity: Local anaesthetic
Principle: It consists of two steps: Step 1: Reduction of p-nitro benzoic acid to p-amino benzoic acid. Step 2: Esterification of carboxylic acid to form benzocaine.
Step1: Preparation of p-aminobenzoic acid.
Chemicals: p-nitro benzoic acid- 5.1 gm ConcHCl, Ethanol Tin metal. Conc.NH3
Apparatus required: 1 lit R.B. flask, reflux condenser & 1 lit beaker.
Procedure: Place 5gms of p-nitro benzoic acid in 1 litre RB flask, to this add 12 gms of tin, 25mL conc. HCl. Fit with reflux condenser, heat the mixture gently until the reaction commences, and remove the flame. Shake the flask frequently and take care that the insoluble acid adhering to the side of the flask is transferred to the reaction mixture. Occasional gentle warming may be necessary. After about 20 mins, most of the Tin would have reacted and a clear solution remains. Allow it to cool and decant the liquid into a 1 litre beaker. Wash the reminder tin by decantation with 15 mL of water and add the washings to the contents of
the beaker. Add conc. NH3solution until the solution is just alkaline to litmus. Filter off the precipitate of hydrated Tin oxide and wash well with water. Filter off any solid which separates. Acidify the liquid with glacial acetic acid and evaporate on water bath until the crystals start separating. Cool in ice andfilter the crystal at the pump.
Recrystallisation: Solvent –alcohol
Yield: 4.1 gms M.P:1920C
Department of Chemistry, RBVRRWC 93 2017-2018
Department of Chemistry, RBVRRWC 94 2017-2018
Step 2: Esterification of p-amino benzoic acid to ethyl p-amino benzoate:
Chemicals required: 4gms of p-amino benzoic acid-4gms 30 mL of absolute ethanol Dry HCl gas.
Apparatus required: 250 mL RB flask.
Procedure: Place 30mLof absolute ethanol taken into a 500mL 2-necked Round bottomed flask and dry HCl gas was passed through it for 15 minutes. Introduce 4gms of p-amino benzoic acid to the flask fitted with condenser and reflux the mixture for 2 hours. On cooling, the reaction mixture settled to a solid mass of hydrochloride of ethyl p-amino benzoate. The hot solution is poured into excess water and sodium carbonate was added to the clear solution until it was neutral to litmus. The precipitate filtered at the pump and dried in air.
Recrystallisation: Solvent –Alcohol.
Yield: 2 grms
M.P:910C
Dose: Topical as 1 to 20% of aerosol cream or ointment to the skin
Department of Chemistry, RBVRRWC 95 2017-2018
6- METHYL URACIL
General reaction O O O O S KOH NH NH Cl CH2COOH O H2N NH2 N O Ethylacetoacetate N S Thiourea H H 6-Methyl Uracil Mechanism
O O OH O O O O OEt OEt H N NH H 2 2 H N NH2 H N N H H S S S
-H2O -EtOH
O O O
Cl CH2COOH N NH H2O N NH N NH
H O S H O S 2 S H H O O O
H N NH HN NH - H2S N NH H O SH O O 6-Methyl Uracil
Department of Chemistry, RBVRRWC 96 2017-2018
6-METHYL URACIL
Aim: To synthesize anti cancer drug.
Chemical name: 6-methyl - 2, 4-dioxo pyrimidine
Pharmacological activity:Anti Cancer drug.
Principle: Synthesis of 6-methyl uracil involves the general pyrimidine synthesis, it involves the condensation of ethyl acetoacetate and thiourea in presence of a base. The thiopyrimidine derivative obtained is treated with chloroacetic acid which results in the formation of 6-methyl uracil.
Step 1: Condensation of ethylacetoacetate and thiourea.
Chemicals:Thiourea – 3.8 gms, Ethylaceto acetate – 7.4mL, Alcohol – 5mL, KOH – 3.3 gms, Chloro acetic acid in water – 10mL, water – 5mL, HCl quantity sufficient.
Apparatus required: R.B flask &reflux condensor.
Procedure: Take 3.8 grams of thiourea, 7.4 mL of ethyl aceto acetate, 5mL of alcohol in Round bottomed flask. Add carefully a solution of KOH (3.39 gm in 5mL water) with constant stirring. Heat the mixture under the reflux for 2 hours. Acidify the resulting solution of crystalline mass by the addition of conc. HCl and then cool and filter the product.
Recrystallisation: Solvent-alcohol Yield: 4 gms
Step -2: Synthesis of thiopyrimidine to 6-methyl-uracil
Chemicals required: 7mL of chloro acetic acid in 10mL of water.
Apparatus required: R.B flask & reflux condenser.
Procedure: Take 4gms of thiopyrimidine derivative into a RB flask and add 7mL of chloro acetic acid in 10 mL of water and heat the mixture under reflux for 3 hours. Filter and crystallize it.
Uses: Nitrogen base for the genetic material. Drug intermediate for anti cancer drug. M.P: 3180C
Department of Chemistry, RBVRRWC 97 2017-2018
Department of Chemistry, RBVRRWC 98 2017-2018
CHLORBUTOL (CHLORITONE)
Aim: To prepare an anti-bacterial drug (chlorbutol)
Chemical name: 1, 1, 1-trichloro-2-methyl -2-propanol
Pharmacological activity: Local anaesthetic
Principle:Chlorbutol also known as chloritone is a trichloro derivative of tertiary butyl alcohol. The reaction involves the generation of carbanion by the action of base on chloroform. Nucleophilic addition of carbanion to carbonyl carbon of acetone results in the formation of chlorbutol.
Procedure: 2.5gms of KOH was taken in a beaker and add 7.5mL of chloroform. 13mL of acetone was added slowly until a solid mass was obtained and was kept aside for 24hrs. The chloritone was then filtered, dried and stored in desiccator.
Yield: 1 gms
M.P:1080C
Category: It is active at about 0.5% as a preservative. It is used topically as a solution in clove oil as a dental analgesic. It has mild local anaesthetic activity.
Department of Chemistry, RBVRRWC 99 2017-2018
Department of Chemistry, RBVRRWC 100 2017-2018
SULPHANILAMIDE
Aim: To synthesise an antibacterial drug (sulphanilamide)
Chemical name: 4-aminobenzenesulphonamide
Pharmacological activity: An antibacterial drug cures by retarding the growth of the disease causing bacteria.
Principle: Synthesis of sulphonamide involves three steps.
Step 1: Electrophilic substitution of chlorosulphonyl group in the para position of acetanilide.
Step 2: Para acetamidobenzenesulphonyl chloride is converted into p- acetamido benzene sulphonamide.
Step 3: Hydrolysis of p-acetamido benzene sulphonamide results in the formation of Sulphanilamide (p-amino benzene sulphanilamide)
Step 1: Preparation of p-acetamidobenzene sulphonyl chloride:
Chemicals: Acetanilide-3gms Chlorosulphonic acid-8mL
Apparatus required: R.B flask & condenser.
Procedure: Take 8mLchlorosulphonic acid in R.B flask and add 3 gm of acetanilide with cooling and stirring. The R.B flask is fitted with water condenser and heated it to about 60-70oC for 15 – 20 mints on a water bath. Cool to room temp. And pour these contents into crushed ice, p- acetamido benzene sulfonyl chloride separates out. Filter at pump.
Recrystallisation:Solvent – alcohol
M.P:142-1450C
Department of Chemistry, RBVRRWC 101 2017-2018
Department of Chemistry, RBVRRWC 102 2017-2018
Step 2: Preparation of p-acetamido benzene sulphonamide.
Chemicals: 6N Ammonia Dil. sulphuric acid p-acetamido benzene sulfonyl chloride
Apparatus required:concial flask &thermometer.
Procedure: The above crude damp sulphonyl chloride was taken in a conical flask and slowly add 6N ammonia solution till a smooth paste is obtained. Heat at 700C for 20 minutes with constant stirring. Cool to room temperature. Acidify with dilute sulphuric acid. Filter the precipitate. Wash with water and filter
Recrystallisation: Solvent- water.
M.P: 2190C
Step 3: Preparation of sulphanilamide
Chemicals: p-acetamido benzene sulphonamide-2gm Conc.HCl Sodium carbonate
Procedure: Take 2 gm of p-acetamido benzene sulphonamide, 3mL of conc. HCl and 5mL of water into a clean R.B flask then boiled gently under reflux for 1 hr. Transfer into 250 mL beaker and powdered sodium carbonate in small quantity is added. Sulphanilamide separates out on cooling. Filter the product.
Uses: Sulphanilamide is used as an anti-bacterial agent. It has bacteriostatic action against disease causing bacteria like streptococci.
Recrystallisation: Solvent– Alcohol
Yield: 1 gm
M.P:1080C
Department of Chemistry, RBVRRWC 103 2017-2018
FLOURESCEIN General Reaction
HO O O HO OH HO OH
Anhydrous O O ZnCl2 O OH
O Mechanism
O O HO OH O O ZnCl O 2 O ZnCl2 ZnCl2 O O O
HO HO OH HO OH HO OH OH O C O H COOZnCl2 COOZnCl2
H OH H HO O OH HO O O - 2H2O
HO H H COOZnCl2 COOZnCl2
HO O O
O ZnCl2 OH
Flourescein
Department of Chemistry, RBVRRWC 104 2017-2018
FLOURESCEIN
Aim: To synthesise a diagnostic agent (Flourescein). Pharmacological activity: It is a diagnostic aid (circulation time, corned thermo indicator)
Principle: This reaction is an example of condensation of phenol with carboxylic acid or carboxylic acid anhydrides. Two moles of resorcinol condense with one mole of phthalic anhydride to produce flourescein.
Chemicals:Phthalic anhydride – 1.5gm Resorcinol – 2.2gms.
Apparatus: Conical flask, oil bath, stoppered tube, mortar, thermometer.
Procedure: Grind together in a mortar 1.5g of phthalic anhydride and 2.2 gm of resorcinol and transfer the mixture to a conical flask. Support the flask in an oil bath and heat to 1800C. While the oil bath is being heated, weigh out rapidly 0.7gm of anhydrous ZnCl2 immediately grind to a coarse powder in a mortar and place it in a stoppered tube. (If the contents of the bottle appear moist dry it by fusing it in a porcelain dish). Add ZnCl2in small portion with stirring by means of thermometer to the mixture in the flask. Continue heating at 1800C with stirring at intervals of two to three minutes until the solution becomes so viscous. The resulting Dark red mass consist largely a mixture of flourescein and ZnCl2together with basic Zn salt. Allow the temperature to fall to about 900C and then add 20 mL of water and 1mL of concentrated HCl to the reaction mixture then raise the temperature of the oil bath until the water boils. Continue boiling until the reaction mixture is disintegrated and all zinc salts have dissolved. Filter the insoluble residue at the pump. Grind it with water in mortar and filter again.
Recrystallisation: Solvent – alcohol
Yield: 3 gms
M.P:3140C
Department of Chemistry, RBVRRWC 105 2017-2018
ANTIPYRINE
General Reaction CH 3 H C H C 3 C O 3 DMS N NH NH2 CH2 HN H C O O 3 N N C O Ph Ph OC H 2 5 Antipyrine Mechanism
Step 1: Synthesis of phenyl methyl pyrazolone
O O O OEt OH OEt
O NH O Ph NH NH2 HN O H NH Ph N Ph H
H H C OH 3 O - H O HN 2 N O OEt - C2H5OH HN N Ph H phenyl methyl pyrazolone Ph
Step 2: Methylation of phenyl methyl pyrazolone
O O
H3C O S OCH3 O S OCH CH3 3 O O H3C H C 3 H3C HN NaOH -H O N N H O N N H3C N O Ph H3C CH3 Ph Ph Antipyrine
Department of Chemistry, RBVRRWC 106 2017-2018
ANTIPYRINE
Aim: Synthesis of an Anti - epileptic drug (Antipyrine)
Chemical name: 1-phenyl -3- methyl- 5 – Pyrazalone
Pharmacological activity: An anti-epileptic drug is the one which cures hysteric condition, by acting on nervous system.
Principle: Synthesis of antipyrine involves two steps: Step 1: Condensation of ethylacetoacetate and phenyl hydrazine with the elimination of water molecule to form phenyl methyl pyrazolone. Step 2: Methylation of the phenyl methyl pyrazolone to form antipyrine.
Chemicals required: Ethyl acetoacetate-6.2mL Phenyl Hydrazine-5mL Acetic Acid-0.5mL
Step 1: Synthesis of phenyl methyl pyrazolone:
Mix 6.2mL ethyl acetoacetate, 5mL phenyl hydrazine and 0.5mL Acetic acid in a china dish. Heat the mixture on water bath for1½ an hr. Stir with a glass rod. Allow the heavy reddish syrup to cool and add 20 mL of ether. Stir vigorously and filter the crystals at the vaccum pump and wash thoroughly with ether. Recrystallize the product from equal volumes of water & ethanol
Step II: Methylation of phenyl methyl pyrazolone:
Place a solution of 1gm sodium hydroxide in a small volume of water and also a solution of 4.4gm of phenyl methyl pyrazolone in 2mL of methanol. Warm on a water bath for few minutes and add 2.7 mL of dimethyl sulfate. Reflux for 1 hr. Cool with continuous stirring. Add hot water to the residue, filter from impurities, extract the antipyrine with benzene.
Uses: Antipyrine is an anticonvulsant, antipyretic & analgesic
Recrystallisation: Solvent– benzene
Yield: 3.5 grms M.P: 1130C
Department of Chemistry, RBVRRWC 107 2017-2018
Department of Chemistry, RBVRRWC 108 2017-2018
SEPARATIONS OF ORGANIC BINARY & TERNARY MIXTURES
Department of Chemistry, RBVRRWC 109 2017-2018
SEPARATION OF ORGANIC BINARY AND TERNARY MIXTURES
REPORTING PROCEDURE OF SEPARATION MIXTURE: 1. Physical state of the mixture:
Solid-Solid or Solid-Liquid or Liquid-Liquid.
2. Solubility of the Mixture:
S.No Ether 10% NaHCO3 10% NaOH Dil. HCl
3. Separation chart:
4. Separating reagent:
5. Solubility of each component:
S.No. Ether H2O 10% 10% Dil.HCl Conc. Inference NaHCO3 NaOH H2SO4
6. Writing Chemical equation for Solubility and Regeneration.
7. Physical constant (B.P/M.P):
8. Reporting of two components:
Department of Chemistry, RBVRRWC 110 2017-2018
Following Procedure separates the Organic binary mixture: 1. Physical state of the mixture: Solid-Solid / Solid-Liquid / Liquid-Liquid.
2. Solubility of the Mixture: One of the component in a binary mixture may be soluble in any one of the reagents NaHCO3/ NaOH/ dil.HCl. Based on its solubility the mixture is separated into individual components. If one of the component is insoluble in ether, then ether will be the separating reagent.
S.No Ether 10% 10% Dil.HCl Inference NaHCO3 NaOH
1. + + + - Separating reagent is 10% NaHCO3
2. + - + - Separating reagent is 10% NaOH
3. + - - + Separating reagent is Dil. HCl
4. - Separating reagent is ether
Solubility Procedure: Take about 100mg of the given mixture in a test tube and then add 10% NaHCO3 solution, shake well and filter. The filtrate is neutralized with conc. HCl. On neutralization if one of the component separates that indicates the mixture solubility as 10% NaHCO3 and if nothing separates on neutralization that indicates the mixture is insoluble in 10% NaHCO3. Then the procedure is to be continued with 10% NaOH. If NaOH is also negative then repeat the same procedure with dil. HCl and neutralize with NaOH.
Department of Chemistry, RBVRRWC 111 2017-2018
Separation Procedure: 1. If physical state of the mixture is Solid-Solid: Transfer the entire mixture into a conical flask and repeatedly extract with the reagent in which the mixture is soluble (NaHCO3/ NaOH/ dil.HCl) and filter. The completion of the mixture separation is checked by neutralization of the last drops of the filtrate. If no solid separtaes that indicates the completion of separation and if solid separates the process is to be repeated until no precipitation occurs on neutralization. After the separation, combine all the filtrates, neutralize and filter. The solid obtained is component-I.
2. The solid insoluble in the reagent is component-II which is washed thoroughly with water and dried.
3. If physical state of the mixture is Solid-Liquid or Liquid-Liquid:
Transfer the mixture into a beaker add ether and stir well. If one of the component is insoluble in ether, then ether is the reagent for separation. If both components are soluble in ether transfer the mixture into a separating funnel and check the solubility in NaHCO3/ NaOH/ dil.HCl. Separate the mixture based on its solubilty. The flow Chart for the binary mixture is as follows: I. Solid-Solid mixture: Solid-Solid mixture
Extract repeatedly with separating reagent ( NaHCO3/ NaOH/ DilHCl) &filter
Aqueous Filtrate Residue Neutralize with appropriate Wash with water Reagent& filter & dry Component-I Component-II
Department of Chemistry, RBVRRWC 112 2017-2018
II. Solid-Liquid or Liquid-Liquid:
Solid-liquid (or) liquid –liquid mixture
Add ether
One component insoluble Both components soluble
Filter & wash with ether Transfer into sperating funnel and extract
with the separating reagent NaHC03/NaOH/ DilHCl
Residue Filtrate
solid Remove ether
Component – 1 on water bath Aqueous Layer` Ether layer
(carbohydrate) Component II Neutralise with Dry and distill off ether
appropriate reagent Component II
If solid appears
filter. If liquid
appears – extract
with ether and
evaporate
` Component –I
Department of Chemistry, RBVRRWC 113 2017-2018
Department of Chemistry, RBVRRWC 114 2017-2018
The possible combination of binary and ternary mixtures:
Binary mixtures: 1. Strong acid + Neutral including hydrocarbons.
2. Strong acid + Weak acid
3. Weak acid + Neutral including hydrocarbons
4. Base + hydrocarbon
5. Carbohydrate + Weak acid
6. Carbohydrate + Strong acid ( other than p-nitro benzoic acid)
Ternary mixtures:
1. Strong acid + Weak acid + Neutral
2. Carbohydrate + Weak acid + Neutral
3. Base + Weak acid+ hydrocarbon
4. Carbohydrate + Strong acid ( other than p-nitro benzoic acid) + Neutral
Department of Chemistry, RBVRRWC 115 2017-2018
Department of Chemistry, RBVRRWC 116 2017-2018
QUALITATIVE ANALYSIS OF ORGANIC COMPOUNDS
Department of Chemistry, RBVRRWC 117 2017-2018
QUALITATIVE ANALYSIS OF ORGANIC COMPOUNDS
The aim is to identify the given organic compound by the following qualitative tests. I. Preliminary tests:
a) Physical state: Solid / Liquid.
b) Physical constant: M.P for solids / B.P for liquids c) Ignition test: Take 2 drops of the liquid or 20 mg of the solid in a nickel spatula and heat on the flame. If the compound burns with the sooty flame it is an aromatic compound (or) if it burns with a non- sooty flame the compound is aliphatic. II. Extra elements:
Lassaignes Test: Heat a small piece of sodium metal in a fusion tube till melts and becomes red hot, add compound to it and heat to red hot. Drop the fusion tube into mortar containing 5-10mL of distilled water and cover with wire guage. Grind it along with glass pieces and filter. This is called sodium fusion extract.
Test for the presence of Nitrogen, Sulphur, & Halogens in the given compound by Lassaignes test using sodium fusion extract. Detailed procedure follows.
S.No Experiment Observation Inference
1. Test for Nitrogen To 2mL of the extract add a Prussian blue coloris Nitrogen is present. pinch of solid ferrous observed. sulphate and heat it to boiling. Add carefully 3 or 4 drops of dil. H2SO4.
2. Test for Halogens To 2mL of the extract add 4 White or pale yellow Indicates the presence drops of dil. nitric acid and precipitate. of chloride/ heat to boil for 5 minutes. bromide/Iodide Cool and add few drops of silver nitrate.
Department of Chemistry, RBVRRWC 118 2017-2018
a.To the above ppt. Add dil Ppt. is soluble Is chloride ammonia solution and shake. Ppt. is sparingly soluble Is bromide Ppt. is insoluble Is iodide
b.To 5-6 drops of the extract CCl4 layer changes to Bromide is confirmed add 1 mL of CCl4 and one orange brown colour mL of KMnO4 solution and shake well & one drop of acid
c. To 5-6 drops of the extract CCl4 layer changes to Iodide is confirmed add 1 mL of CCl4 and 1 mL purple colour of 20% sodium nitrite solution and shake well.
Test for Sulphur 3. To 1 mL of the extract add 1 Purple or violet red Sulphur is present mL of freshly prepared colour is observed. sodium nitroprusside (푁푎2[Fe(CN)5NO] 2퐻2O III. Solubility: Test the solubility of the compound separately in water, ether, 5% aq sodium bicarbonate, 5% aq sodium hydroxide solution, dilHCl& conc. Sulphuric acid.
S. No. 푯ퟐO ETHER 5% 5% Dil. HCl Conc. CLASS NaHC푶ퟑ NaOH 푯ퟐ푺푶ퟒ 1. - + + + - + /- Strong acid (carboxylic acid) 2. - + - + - + /- Weak acid (Phenol)
3. - + - - + + /- Bases (amines)
4. - + - - - + Neutral (aldehydes, ketones, amides, anilides, esters, ethers &nitro hydrocarbons) Neutral (Polynuclear - + - - - - aromatic and halogenated hydrocarbons.)
5. + - + + + + Miscellaneous (Carbohydrates Urea and thiourea)
Department of Chemistry, RBVRRWC 119 2017-2018
Note:
1. The solubility of the carboxylic acid can be confirmed by re precipitating the acid by neutralizing with dilHCl. 2. The solubility of the weak acid can be confirmed by re precipitating the acid by neutralizing with dilHCl. 3. Sometimes amines forms salts (solids) on adding HCl in such cases water can be added to dissolve the solid, confirm the solubility by neutralizing with dilNaOH.
4. Conc.H2SO4can nearly act as a solvent for a number of neutral compounds, the solubility in conc.sulphuric acid may be tested only when
the compound is insoluble in all other solvents. If insoluble in H2SO4 the compound may be a polynuclear aromatic / halogenated hydrocarbon.
IV. Functional group analysis:
Identify the functional groups present in the compound by qualitative tests. Wherever possible two confirmative tests should be carried out. The details are given in the table.
V. Derivatives:
Once the functional group is identified it has to be confirmed by preparing one or two derivatives (solid) and by determining their melting points.
VI. Reporting:
Report your observation and conclusions as below:
Based on preliminary tests, extra elements, solubility, functional group analysis and derivatives the given compound is identified and confirmed as ------
Department of Chemistry, RBVRRWC 120 2017-2018
FUNCTIONAL GROUP ANALYSIS OF CARBOXYLIC ACIDS
S. No Experiment Observation Inference 1. Solubility in sodium Bicarbonate solution: To 50mg of the The compound Presence of compound add 1mL of dissolves with COOH group 10% sodium bicarbonate effervescence. solution. To the clear solution add The compound is Compound is a a few drops of conc. regenerated. carboxylic acid. HCl. 2. Esterification: To 50mg of the Fruity odour is Compound is a compound add 1 mL of observed. carboxylic acid ethyl alcohol or methanol and add 1mL of conc. H2SO4and heat the mixture in hot water bath for 5mts. Pour the contents into cold 10% sodium bicarbonate solution. 3. Ferric chloride colouration: To 50mg of the A brownish violet or Carboxylic acid is compound add few reddish brown ppt is confirmed drops of ammonium formed. hydroxide until alkaline to litmus. Add 1 mL of neutral Ferric chloride solution.
Derivative: Amide &Anilide.
Preparation of acid chloride:
Transfer 1gm of carboxylic acid into a dry round bottomed flask. Add thionyl chloride till the solid just dips in it. Reflux the reaction mixture on a water bath with a water condenser for 15 min. Transfer the acid chloride
Department of Chemistry, RBVRRWC 121 2017-2018
into two small beakers. Cool it in ice, see that no water enters the beaker (if the water enters the acid chloride, acid chloride undergoes hydrolysis back to carboxylic acid). Measure 2 mL of ammonia in one test tube (dry) & 2mL of aniline in another dry test tube.
Amide preparation: Add ammonia drop wise to the acid chloride taken in one beaker till a solid ppt if formed. Cool for 5min.
Anilide preparation: Add aniline drop wise to acid chloride taken in second beaker till a solid ppt is formed. Cool for 5min.
PHENOLS:
S. No. Experiment Observation Inference 1. Neutral FeCl3 test: Take 5 drops of the Green/brown/violet/ Compound may be a compound and add a few blue color develops. phenol. drops of freshly prepared neutral FeCl3solution.
2. Phthalein fusion test: To 100mg of the Pink color develops Compound is phenol compound in a test tube add equal amounts of Red/blue/fluorescent Compound is a phthalic anhydride and color develops. substituted phenol. heat. Add 2 drops of conc.H2SO4. Stir the mixture, cool and add 2-3 drops of this mixture into a beaker containing 5mL of 10% NaOH.
3. Reaction with bromine water:
To 1 drop of phenol add Formation of an Phenolic nature is bromine water until yellowish white confirmed. orange color persists. precipitate. Pour it in a beaker containing ice cold water.
Department of Chemistry, RBVRRWC 122 2017-2018
4. Libermann reaction: Take 1 or 2 crystals of NaNO2 in a dry test tube, Deep green or deep Phenolic nature is add 0.5 gms of phenol blue color develops confirmed. and heat for 1 mL. Allow which on dilution it to cool and add twice changes to red color. the volume of conc. H2SO4 5. Diazotisation: Take 2 or 3 drops of aniline in a test tube add Formation of red Confirms phenol. conc. HCl until aniline orange dye dissolves and add 3 mL of cold water. Cool the test tube in ice to 00C. Add few drops of 20% NaNO2 solution (which is also cooled to 00C) to the aniline solution. Add this diazonium solution to a cold solution of phenol in 10mL of 10% NaOH solution. Maintain the temperature at 00C
Derivatives:
A: Bromo derivative: Transfer 1 gm of the phenol into a beaker and
dissolve in 3 mL of methanol if the compound is a solid, then add Br2in
acetic acid until red color of Br2is persistent. Keep aside for 5-10 mts. Add ice cold water to the mixture and filter the solid separated out.
B: Benzoyl derivative:
Transfer 500mg of the compound into a conical flask and add 10mL of 15% NaOH solution and shake the mixture till all the phenol dissolves in the NaOH then add 2mL of Benzoyl chloride and cork the flask. shake the flask vigorously for 10mts where by solid benzoyl derivative separates out. Filter & wash with 10% sodium carbonate solution to remove excess of Benzoyl chloride & again wash with water to remove the carbonate.
Department of Chemistry, RBVRRWC 123 2017-2018
C: Aryloxy derivative:
Transfer 1gm of phenol into a round bottomed flask and add 10mL of 1%NaOH solution. And add chloroacetic acid, reflux the mixture with a water condenser on a small flame for half an hour, cool the reaction mixture & neutralize with HCl. An aryloxy derivative got separated.
D. Methylation for β-Naphthol:
Transfer 500mg of β-Naphthol into a conical flask and dissolve it in 5mL of 15% NaOH solution. Then add 2mL of dimethyl sulphate. Cork the flask and shake vigorously till a buff coloured solid separates out. Filter the β-Naphthyl methyl ether formed.
AMINES:
S. No. Experiment Observation Inference 1. Solubility in dil. HCl: Take 10mg (5 drops) of the The compound The compound may compound and add 15mL of dissolves and a clear be primary/secondary/ dil. HCl. solution is obtained. tertiary amine. 2. Nitrous acid test: Dissolve 50mg of the 1. If liberation of Indicates the substance in 1mL of brown gas with formation of concHCl and dilute with the formation of diazonium ion. 3mL of water. Cool in ice an orangish Primary amine is and add few drops of cold brown solution. confirmed. NaNO2 solution. 2. If yellow oily Indicates the drops separates formation of N- outs. Nitroso amine. Secondary amine is confirmed.
3. Dark red colour Indicates the solution is formation of p- obtained, to this Nitroso amine. add 1mL of 5% Tertiary amine is NaOH. Dark confirmed. green solid separates out.
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4. Reaction with bromine water: To 1 drop/10mg of amine Formation of an Primary amine is add bromine water until yellowish white confirmed. orange color persists. Pour precipitate. it in a beaker containing ice cold water.
5. Diazotisation of primary amine: Take 2 or 3 drops of amine Azo dye is formed. Primary amine is in a test tube, add conc. HCl confirmed. until aniline dissolves and add 3 mL of cold water. Cool the test tube in ice to 00C. Add few drops of 20% NaNO2solution (which is also cooled to 00C) to the aniline solution. Add this diazonium solution to a cold solution of phenol in 10mL of 10% NaOH solution. Maintain the temperature at 00C
Derivatives:
1. Primary / secondary amine:
Bromo derivative: Transfer 1mL of the pri/sec amine into a beaker and
add Br2 in acetic acid until red color of Br2is persistent. Keep aside for 5- 10 mts. Add ice cold water to the mixture where by a white/yellow ppt. separates out.
Benzoyl derivative: Transfer 1mL of the pri/sec amine into a conical flask and add 10mL of 15% NaOH solution and add 20 drops of benzoyl chloride. Cork the flask and shake vigorously till a solid separates out. Filter and wash with carbonate solution followed by water.
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Acetyl derivative: Transfer 1mL of the pri/sec amine into a dry conical flask and add 3mL of acetic anhydride, 3mL of glacial acetic acid and heat on a water bath for 10 mts. Test for completion of reaction by transferring few drops of the mixture into the test tube containing ice cold water. If solid separates out, stop heating otherwise continue heating for some more time. Transfer the reaction mixture into a beaker containing cold water. A solid acetyl derivative separates out.
II. Tertiary amine:
p-Nitroso tertiary amine: Transfer 1 mL of the tertiary amine into a beaker and cool in ice till the temperature reaches 50C. Add 5mL of conc.
HCl, mix well and continue cooling. Transfer 1 spatula of solid NaNO2 into a test tube and dissolve in half test tube of water & cool this in ice to 0 5 C. Now add cold NaNO2 solution drop wise to the cold amine present in the beaker, maintaining the temperature at 50C. The solution becomes red due to the formation of p-Nitroso tertiary amine hydrochloride. Then add 10% NaOH solution to this where by a dark green solid separates out.
Picrate derivative: Transfer 1mL of the tertiary amine into a beaker and add spatula of picric acid and 2-3mL of methanol. Heat the mixture on electrical water bath till the solution becomes clear. Keep it aside for 5mts. An yellow crystalline picrate of tertiary amine separates out.
Carbonyl compounds:
S. No. Experiment Observation Inference 1. 2,4–DNP test: To 2-3 drops of comp. Add An orange ppt. of 2,4- Carbonyl 1mL of 2,4-DNP reagent (if dinitro phenyl compound is compound is solid dissolve it hydrazone is formed present. in few drops of methanol). Keep it in hot water bath for few minutes if no precipitate is formed 2. Bisuphite addition reaction: To 1mL of comp. add 1mL of White addition May be saturated sodium bisulphite product is formed. Aldehyde or solution. ketone.
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3. Tollens test: To 1mL of comp. add 5mL of A silver mirror is Aldehyde tollens reagent and heat. deposited (or black group is ppt) confirmed. 4. Fehlings test: To 1mL of comp add 1mL of Red colored ppt. is Na2CO3 solution and 1mL of formed (aromatic Aldehyde is Fehlings solution A and 1mL aldehydes react very confirmed. of Fehlings solution B. Boil slowly) the mixture for 2-3mts.
Note: If all the tests are negative except 2,4- DNP test then the compound may be ketone.
Preparation of Tollens reagent: Take 5mL of AgNO3 solution in a clean test tube and add 2 drops of 10% NaOH solution. A grey ppt. is formed. To this add
NH4OH drop wise until the grey precipitate dissolves. This is known as Tollens reagent.
Iodoform test for Methyl ketone:
S. No. Experiment Observation Inference 1. To 3 drops of compound add A pale yellow ppt. Methyl ketone is 10 mL of 20%aq NaOH and (iodoform) is formed. confirmed. shake well add gradually with shaking kI+I2 solution till dark If no ppt. is formed after The ketone is not colour of iodine persist. Now prolonged heating. methyl ketone. warm the solution on a hot water bath for 10min 2. To 0.5mL of ketone shakewell. A pale yellow ppt. Methyl ketone is add carefully 3mL of 10% Kl (iodoform) is formed confirmed. solution and 10mL of freshly prepared NaOCl and shake vigorously.
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Test for Benzophenone:
S. Experiment Observation Inference No. 1. To 50mg of benzophenone The mixture turns Benzophenone taken in a dry test tube, add green due to the free is confirmed. 1 gm of naphthalene, mix radical formation. and heat until melts. Add a small piece of sodium metal and heat again.
Derivatives for carbonyl compounds (aldehydes & ketones)
A: Preparation of oxime:Transfer 1mL or 500 mg of the carbonyl compound into a small beaker and add 5mL of methanol, 100 mg of hydroxyl amine hydrochloride followed by 1gm of sodium acetate. Heat the mixture on an electrical water bath for 15 min, on cooling white crystalline oxime separates out.
B: Preparation of Semi carbazone: Transfer 1 mL or 500 mg of the carbonyl compound into a small beaker and add 5mL of methanol, 100mg of semicarbazide hydrochloride followed by 1 gm of sodium acetate. Heat the mixture on an electrical water bath for 15 min, on cooling white crystalline semicarbazone separates out.
C: Preparation of Phenyl hydrazone: Transfer 1 mL or 500 mg of the carbonyl compound into a small beaker and add 5mL of methanol, 100 mg of phenyl hydrazine hydrochloride followed by 1gm of sodium acetate and 1mL of glacial acetic acid. Heat the mixture on an electrical water bath for 5 min, on cooling hydrazone separates out.
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AMIDES:
S. No. Experiment Observation Inference 1. Hydrolysis: Take 5mg of compound in a Ammonia gas is Amide is confirmed. test tube and add 2mL of liberated. Turns red NaOH and heat for 2min on litmus to blue. a burner. (Test with litmus). Add HCl to the above White ppt. of Amide is confirmed. alkaline solution. carboxylic acid is formed. Derivatives:
Hydrolysis of amide: Transfer 1gm of amide into a conical flask, add 15mL of 20% NaOH solution and heat it on a Bunsen burner till the mixture boils. Cool the reaction mixture and neutralize with conc. HCl. A white ppt. of carboxylic acid separates out with loss of ammonia.
NITRO HYDROCARBONS
S. No. Experiment Observation Inference 1. Barker-Mullikon test: Dissolve 50mg of the Black or grey ppt. / Nitro compound in 1mL of ethanol silver mirror hydrocarbon is and add 50mg of solid NH4Cl formation. confirmed. and 50mg of zinc dust. Heat the mixture to boiling &filter. To the filtrate add tollens reagent and heat it on the waterbath Note: If the given compound contains Nitrogen and gives negative test for amides, urea & nitro hydrocarbons, then test for anilides.
Derivative:
Dinitration: Transfer 1mL of nitrobenzene into a small round bottomed
flask, then add nitrating mixture (2mL of fuming HNO3 + 3mL of
conc.H2SO4) to it and heat the mixture on water bath with an air condenser for 15min. Transfer the reaction mixture into a beaker containing cold water. Pale yellow solid of m-dinitrobenzene separates out.
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ANILIDES:
A. Test for Benzanilide:
S. No. Experiment Observation Inference 1. To 50mg of the compound add Carboxylic part Benzanilide 5mL of conc. H2SO4...warm of anilides is confirmed. carefully separates as solid.
Derivatives:
Transfer 1 gm of anilide into a round bottomed flask and add 20mL of
70% H2SO4 and reflux with a water condenser on a small flame for 10min. Then cool the reaction mixture where by a white solid of aromatic carboxylic acid separates out. Aniline forms anilinium sulphate which is soluble in water and can be eliminated by filtration.
B. Test for Acetanilide
S. No. Experiment Observation Inference 1. To 50mg of the Formation of oily droplets Acetanilide compound add 5mL of indicates the amine part is conc. H2SO4...warm which is extracted with ether. confirmed carefully and neutralize Evaporate ether and test for with dil. NaOH primary amine.(any 10 test)
Derivatives:
Bromo derivative:To 1gm of acetanilide add bromine in acetic acid till the red color of bromine persists. Keep it aside for 15 min. Pour into cold water where by parabromo acetanilide separates out.
Nitro derivative: Dissolve 1gm of dry acetanilide in 1mL of glacial acetic acid in a 100 mL beaker. Surround the beaker with ice and add
a cold mixture of 1mL of conc.HNO3& 0.5mL of conc. 0 H2SO4maintaining the temp below 5 C. Allow it to stand for 10min. Pour into crushed ice, p-nitro acetanilide separates out.
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ESTERS:
S. No. Experiment Observation Inference 1. Hydroxamic acid test:
To a drop of the compound Deep violet or deep Ester is add 100mg of solid hydroxyl reddish colour confirmed. amine hydrochloride and develops due to the 5mL of 10% NaOH solution. formation of Boil the mixture on a bunsen hydroxamic acid. flame for 2-3min. Cool and acidify with dil. HCl. To this solution add few drops of neutral FeCl3 solution. 2. Hydrolysis:
Take 2mL of ester in a 50mL Ester undergoes Ester is round bottomed flask and hydrolysis to give an confirmed. add 20mL of 30% NaOH alcohol and acid. The solution and reflux using a alcohol being liquid water condenser for half an floats on the mixture hour. Cool the mixture and and acid gets neutralize with conc. HCl precipitated by neutralisation
Derivatives:
Hydrolysis: Take 2mL of ester in a 50mL round bottomed flask and add 20mL of 30% NaOH solution and reflux using a water condenser on a Bunsen burner for half an hour. If there are no oily drops floating on the surface then it indicates the reaction is complete. Otherwise continue the heating for some more time. Then transfer the reaction mixture into a 250mL beaker and neutralize with conc. HCl while cooling. A white ppt. of aromatic carboxylic acid separates out.
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HYDROCARBON:
S. No. Experiment Observation Inference 1. Test with AlCl3:To a few mg of the compound or 0.2mL of Orange colour develops Compound liquid add 3mL CHCl3 and on the sides of test tube. may be halo shake well. Then transfer a hydrocarbon. pinch of AlCl3 into a dry test tube and sublime. Then add Purple or blue or green Compound CHCl3 to the sublimed AlCl3 colour develops. may be poly such that the CHCl3 layer hydrocarbon. touches the AlCl3
Derivatives:
Nitration: To 1mL of hydrocarbon add a mixture of 2 mL of conc.
HNO3& 4 mL of conc.H2SO4 and heat the mixture on water bath for 20 min and transfer the mixture into a beaker containing cold water.
Picrate: Transfer 1mL of the compound into a small beaker, add 3mL of methanol and one spatula full of picric acid. Heat the reaction mixture on a water bath for 15min. Keep aside, where by a pale crystalline picrate separates out.
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MISCELLANEOUS GROUP:
A: CARBOHYDRATES:
S. No. Experiment Observation Inference 1. Molisch test: Dissolve 2mg of the compound A deep violet color is Carbohydrate is in 4mL of water and add 3-4 formed at the junction confirmed. drops of alc.α-naphthol. of two layers. Then add 2mL of conc. H2SO4carefully from the sides of the test tube. 2. 2, 4-DNP test: To 5 mg of the compound in 1 Orange ppt. separates. Presence of mL of water, add 1mL of 2, 4- carbonyl group. DNP reagent. 3. Tollens test: Dissolve 1mg of the compound Silver mirror is Aldose is in 1mL of water and add 5 mL deposited confirmed. of tollens reagent. Heat the mixture on water bath for 5-10 No Silver mirror. Ketose is min. confirmed 4. Rapid furfural test: Dissolve 20mg of the In case of fructose May be compound in 1mL of water and violet color is formed fructose. add 1mL of α-naphthol solution immediately. & 2-3 drops of conc. HCl. If the color is May be glucose. developed slowly at RT but develops on heating in a water bath.
Preparation of Tollens reagent: Take 5mL of AgNO3 solution in a clean test tube and add 2 drops of 10% NaOH solution. A grey ppt. is formed. To this add
NH4OH drop wise until the grey precipitate dissolves. This is known as Tollens reagent.
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Derivatives:
Osazone derivative: Dissolve 1gm of carbohydrate in 5mL of water then add 3mL of glacial acetic acid and 5mL phenyl hydrazine in a boiling tube and heat on water bath for 15min. An yellow crystalline phenyl osazone separates out.
Benzoylation: Transfer 1gm of carbohydrate into a conical flask and add 10mL of 20% NaOH followed by 2mL of benzoyl chloride. Cork the flask and shake vigorously for 10min where by a white solid of penta benzoyl derivative separates out.
B: UREA:
S. Experiment Observation Inference No. 1. Biuret test: Place 20mg of urea in a dry test tube and heat it gently for Copper sulphate colour Urea is a min. The comp melts with changes to purple colour confirmed. liberation of NH3 and resolidifies to form biuret. Dissolve this in 1mL of hot NaOH solution & heat it. Cool and add a drop of CuSO4 solution.
Derivatives:
Nitration: Dissolve 1gm of urea in 5 mL of water taken in a test tube and add 3 mL
of conc. HNO3, mix well with a glass rod. A white crystalline urea nitrate separates out.
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Urea oxalate: Dissolve 1gm of urea in 5 mL of water taken in a test tube and add 3 mL of saturated solution of oxalic acid and shake well. A white solid of urea oxalate separates out.
C: THIOUREA:
Note: If both N & S are present in extra elements test, then test for thiourea.
S. Experiment Observation Inference No. 1. Test with FeCl3:
Take 10mg of the compound Blood red color Thiourea is and heat it on a burner till it develops due to confirmed. melts. Then add 2-3 drops of ammonium CH3COOH followed by a few thiocyanate. drops of potassium ferricyanide.
2. Melt 10mg of thiourea in a dry Green color appears Thiourea is test tube and add few drops of &slowly changes to confirmed. dil.CH3COOH, followed by few blue. drops of potassium ferricyanide.
Derivative: Thiourea:
Benzoylation: Transfer 500mg of thiourea into a dry R.B. flask, add 10mL of ethanol and 3mL of benzoyl chloride to it. Reflux the mixture on a water bath with a water condenser for 30min. Transfer the hot reaction mixture into a dry 100mL beaker and cool in ice. A white crystalline benzoyl thiouranium chloride separates out.
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SPECTRAL ANALYSIS OF UNKNOWN ORGANIC COMPOUNDS
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SPECTRAL ANALYSIS:
The order for interpretation of the Spectral data is as follows:
1. Molecular Formula calculations:
a) The molecular ion M+indicates molecular weight.
b) If the mass is even, there may be zero or even number of Nitrogen’s
and if it is odd there must be odd number of Nitrogen’s in the
compound (Nitrogen Rule).
c) If M+ and M +2 ratio is 1:3 chlorine may be present and if it is 1:1
bromine may be present.
d) Iodine is recognized by the presence of I+ at m/z=127, combined with
a characteristic 127 unit gap in the spectrum corresponding to loss of
iodine radical.
e) If M+2is only 4%, sulphur may be present.
f) Number of carbons can be calculated as = % M+1
1.1% (abundance of C13)
g) Weight of carbons = No. of carbons X 12 =x gms. h) If N/Cl/Br/S present add their mass to mass of carbons. i) No. of hydrogens = Mol. Wt- (wt. of carbons + wt. of heteroatoms) j) If necessary, add appropriate number of oxygen atoms. k) Therefore the molecular formula may be ------
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2. Index of Hydrogen deficiency (OR) Double bond equivalence (DBE):
DBE = No.of C’s – No. of H’s – No. of halogens + No. of N’s +1
2 2 2
If DBE=1 it may be one = bond in open chain or monocyclic saturated system. If DBE=2 it may be two = bonds in open chain or one = bond in cyclic system or may be saturated bicyclic structure If DBE=3 it may be three = bonds in open chain or two = bonds in cyclic system or may be saturated tricyclic structure If DBE=4 it may be one ring and three = bonds i.e. Aromatic ring
If DBE=5 it may be one ring and four = bonds ( 3 = bonds in benzene and one outside)
3. Interpretation of IR Spectral data: To identify the Functional groups using stretching & bending vibrations.
4. Interpretation of UV spectral data: To identify whether aliphatic or aromatic and characteristic chromophoric groups.
5. Interpretation of Proton and Carbon NMR Spectra: To indicate the number and nature of protons & carbons respectively.
6. Proposition of Possible structures: Proposition of Possible structures and confirming the correct structure and deletion of other structures based on consolidated assignments of IR, UV, NMR
7. Mass spectral Fragmentation: Based on the fragment ions and their relative abundance from the spectrum.
8. Reporting the structure: Reporting the structure with Spectral assignments.
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Spectra:
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ANALYSIS OF SPECTRAL DATA:
Aim: To deduce the structure of organic compound from the given spectral data
I. Calculation of Molecular Formula :
M+ M+1 m/z 120 121 RA 80 8 % RA 100 10
Molecular weight is even – it indicates the presence of even number of Nitrogens or no nitrogen
M+1 peak indicates the number of carbons. Number of Carbons =% M+1 / 1.1= 10/1.1= 9.09 Number of carbons = 9; Mass of carbons= 9 X 12 = 108 Remaining mass = 120 -108 =12 Mass is even so there may be even no. of nitrogen’s or no nitrogen If 2 nitrogens are present = 2X14=28. Since N mass exceeding remaining mass, presence of nitrogen is ruled out. If oxygen is present = 1x16= 16 Since Oxygen mass exceeding remaining mass, presence of oxygen is ruled out. So there may be 12 hydrogen’s.
Therefore Molecular Formula = C9H12
II. Double bond Equivalence:
DBE = No.of C’s – No. of H’s – No. of halogens + No. of N’s +1
2 2 2 = 9- 12/2 - 0/2 + 0/2 +1=4 4 double bonds indicates that there may be 4 double bonds in an aliphatic compound or 3 double bonds with one ring, i.e Aromatic ring.
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III. Interpretation of IR:
Vibrational Frequency ( cm-1) Assignment 700 Bending vibrations of tri substituted benzene 840 C-H out of plane bending 1600 C=C stretching 2900 Aliphatic C-H stretching 2901 Aromatic C-H streching
Inference: IR spectra indicates the presence of tri-substituted benzene.
IV. Interpretation of UV:
λmax Transitions Assignment
250nm π – π* BenzenoidChromophore 275nm π – π* Transition of substituted benzene
Inference: indicates the presence of substitution on benzene ring V. Interpretation of Proton NMR:
Chemical Multiplicity No. of No. of Nature of shift divisions H’s protons 2.2 Singlet 2.7/0.9=3 9 3 –CH3 groups attached to benzene ring
6.9 Singlet 0.9/0.9=1 3 Aromatic hydrogen
Inference: NMR data indicates the molecule is highly symmetrical, because only two signals are obtained in PMR.
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VI. Interpretation of C13NMR:
a) Proton decoupled spectra- 3 signals b) Off resonance decoupled spectra- quartet, doublet, singlet
Chemical shift Multiplicity Assignment
Decoupled ORD spectra
21δ Singlet quartet -CH3 group 128δ Singlet doublet -CH of aromatic ring 138δ Singlet singlet Quarternary carbon of aromatic ring
Inference: NMR data indicates the presence of 3 equivalent methyl groups, 3 aromatic protons and there is one quarternary carbon. C13NMR shows the presence of 3 different carbons.
VII. Possible structures:
I structure
II structure
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III Structure
Structure –I is ruled out because it contains two types of methyl groups and two types of aromatic hydrogens in PMR. C-13 NMR shows 6 types of carbons. Structure-II is ruledout because it contains three types of methyl carbons and 6 types of aromatic hydrogens. Structure-III is coinciding with all the spectral data, therefore structure-III is the correct structure of the compound.
VIII. Interpretation of mass spectral data: m/z 120 105 91 77 %RA 81 100 10 20
Fragmentation of Mesitylene:
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IX. Result:
1. Based on the isotopic abundance the molecular formula of the compound
is calculated as C9H12 and based on DBE =4, the compound is identified as tri substituted benzene.
2. IR spectra indicates the presence of trisubstituted benzene.
3. UV spectra indicates the presence of alkyl substitution on benzene ring.
4. NMR spectral data indicates the presence of 3 equivalent methyl groups and 3 equivalent aromatic carbons and one quarternary carbon.
5. Mass fragmentation confirms the structure-III for the given molecular formula. Based on IR, UV, NMR the structure is confirmed as mesitylene i.e. 1,3,5-trimethyl benzene.
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CHROMATOGRAPHY
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INTRODUCTION
Chromatography is a separative technique where by the components of a mixture may be separated by allowing the sample (analyte) to be transported through a placed bed of material (stationary phase) by a fluid mobile phase. If the individual components in the mixture move through the packed bed at different rates then separation will occur, the degree of separation depending on the difference in the rates of migration.
The International Union of Pure and Applied Chemistry (IUPAC) has defined chromatography as a method used primarily for the separation of components of a sample, in which the components are distributed between two phases, one of which is stationary while the other moves.
The Stationary phase may be a solid or a liquid supported on a solid, or a gel. The stationary phase may be packed in a column, spread as a layer or distributed as a film, etc. In these definitions chromatographic bed is used as general term to denote any of the different forms in which the stationary phase may be used.
The Mobile phase may be gaseous or liquid. If the stationary phase is a liquid it must be immobilized in some way (otherwise it would not remain stationary for very long). This can be achieved by coating or chemically bonding the liquid stationary phase to an inert support material, which is then spread onto a flat plate or packed into a column.
Chromatography is a physical method of separating a mixture of compounds.
A Chromatography experiment is carried out in order to:
• Know the number of compounds in a sample • Identify the compounds • Know the relative quantities of the compounds in a sample • Effect quantitative separation of the compounds. • To monitor the chemical reaction.
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The common Chromatographic techniques are:
➢ Column Chromatography (CC) ➢ Thin-layer Chromatography(TLC) ➢ Ion-Exchange Chromatography(IEC) ➢ Gas Chromatography (GC) ➢ Paper Chromatography(PC) ➢ Gas-liquid Chromatography (GLC) and ➢ High-Performance Liquid Chromatography (HPLC).
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SOLVENT FRONT
COMPOUND SPOT
SAMPLE SPOT
Before development After development
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THIN LAYER CHROMATOGRAPHY-I
Aim: To check the purity of the given compound and determine the 푅푓 value of the given compound.
Principle: Thin layer chromatography is mainly an adsorption chromatography technique. The compound spotted on thin layers of silica gel coated on a glass plate gets adsorbed onto the thin layers (stationary phase) & gets partitioned between the thin layers and mobile phase, when the mobile phase percolates through the thin layer. The percolation of mobile phase is by means of capillary forces. As adsorption and partition go on simultaneously, the compound will move along the mobile phase.
Procedure:-
Part-I: Preparation of Slurry:
Prepare a solvent system containing CHCl3 and CH3OH in 2:1 ratio (66mL of CHCl3 and 33mL of CH3OH). Weigh 35gms of silica gel-G of TLC grade, transfer it into a bottle, and then add the prepared solvent system. Shake well and observe that uniform silica slurry is obtained.
Part-II: Preparation of TLC Plates:
Dip two clean and dry TLC plates together in the slurry carefully and remove carefully. A uniform layer of silica gel-G gets adsorbed on plates along with little solvent. Allow the solvent to evaporate by keeping the slides aside for few minutes.
Part-III: Development of Plate:
Take 2-3mL of solvent in TLC development tank & cover with the lid. Keep it for some time so that the tank gets saturated with solvent vapors.
Prepare a saturated solution of given compound in acetone/ CH3OH in a small sample tube. Place a capillary tube inside the solution, take out the capillary tube from the solution as soon as the solution enters into the capillary tube. Spot the solution gently on TLC plate just 5mm above the bottom. The solution from the capillary tube now comes out and gets adsorbed on silica plate. Let solvent on plate evaporate. The point at which the compound is spotted on the plate is called loading point.
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Place gently the plate inside the development tank in a slant position and cover with the lid. Observe that the loading point is above the solvent. Allow the solvent to ascend on the plate by capillary action, compound spotted moves upward direction along with the solvent. Remove the plate from the development tank after the solvent reaches to the maximum height. Then allow the solvent to evaporate.
Part-IV: Detection: a. Iodine blower method:Take a small glass tube with one end being narrow. Place a little cotton on the narrow end & add a few crystals of iodine and again place little cotton. This is called as iodine blower. Blow the iodine through the blower on the development plate to locate the spot. A yellow (or) brown colour spot immediately formed indicates the distance travelled by the compound from loading point. A simple spot obtained indicates that the compound is extremely pure in nature.
b. Iodine chamber method:Take a chamber. Put iodine crystals at the bottom of chamber as a layer. Cover with the lid. Keep it for some time so that the chamber gets saturated with iodine vapor. This is called as iodine chamber. Then keep the developed plate in a slant position in the iodine chamber. Cover with the lid. Keep it for some time so that yellow (or) brown coloured spots develop.
c. U.V. Detection:Keep the developed plate in U.V. Detector. Observe the absorbance. If the compound is fluorescent in nature, fluorescence can be detected at longer wavelengths. Fluorescent compounds can be better detected with U.V. detector.
NOTE:If the spot remains at a loading point or mobility is unsatisfactory, increase the polarity of solvent or solvent mixture in following order.
Petroleum ether / benzene/ chloroform/ ethyl acetate/ acetone/ methyl alcohol/ acetic acid/ water.
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CALCULATION OF Rf VALUE:
푅푓 Value (retardation or retention factor) is characteristic of compound under the given set of conditions. It can be used for qualitative purposes. Measure the distance moved by the compound from the origin. Measure the distance moved or travelled by the solvent front from origin. Then
Distance moved from origin by the compound 푅푓= ------Distance moved from origin by the solvent front
RESULT:
The given compound is ------(pure / not pure)
The solvent system selected on hit and trial basis is ------
The 푅푓 value of compound =
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SOLVENT FRONT
COMPONENT-2
* COMPONENT-1
SAMPLE SPOT LOADING POINT
Before development After development
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THIN LAYER CHROMATOGRAPHY – II
Aim: To separate the components present in the given mixture by means of TLC.
Principle: Thin layer chromatography is mainly an adsorption chromatography technique. The compound spotted on thin layer of silica gel coated on a glass plate gets adsorbed onto the thin layers (stationary phase) & gets partitioned between the thin layers and mobile phase, when the mobile phase percolates through the thin layer. The percolation of mobile phase is by means of capillary forces. As adsorption and partition go on simultaneously, the compound will move along the mobile phase. When more than one component/ analyte are present, movement of components is according to their differential migration rates. The component, which has greater affinity towards the stationary phase, will move later than the one which has relatively lesser affinity towards the stationary phase.
Procedure:
Part-I: Preparation of Slurry:
Prepare a solvent containing CHCl3 and CH3OH in 2:1 ratio (66mL of CHCl3and 33mL of CH3OH). Weigh 35gms of silica gel-G of TLC grade, transfer it into a bottle, and then add the prepared solvent system. Shake well and observe that uniform silica slurry is obtained.
Part-II: Preparation of TLC Plates:
Dip two clean and dry TLC plates together in the slurry carefully and remove carefully. A uniform layer of silica gel-G gets adsorbed on plates along with little solvent. Allow the solvent to evaporate by keeping the slides aside for few minutes.
Part-III: Development of Plate:
Take 2-3mL of solvent in TLC development tank& cover with the lid. Keep it for some time so that the tank gets saturated with solvent vapours.Prepare a saturated solution of given mixture in acetone/ CH3OH in a small sample tube. Place a capillary tube inside the solution; take out the capillary tube from the solution as soon as the solution enters into the capillary tube. Spot the solution gently on TLC plate just 5mm above the bottom. The solution
Department of Chemistry, RBVRRWC 157 2017-2018
Department of Chemistry, RBVRRWC 158 2017-2018
from the capillary tube now comes out and adsorbed on silica plate. Let solvent evaporate on plate. The point at which the compound is spotted on the plate is called loading point. Place gently the plate inside the development tank in a slant position and cover with the lid. Observe that the loading point is above the solvent. Allow the solvent to ascend on the plate by capillary action, the compound spotted move upward direction along with the solvent. Remove the plate from the development tank after the solvent reaches to the maximum height. Then allow the solvent to evaporate.
Part-IV: Detection:
Take a small glass tube with one end being narrow. Place a little cotton on the narrow end & add a few crystals of iodine and again place little cotton. This is an iodine blower. Blow the iodine through the blower on the development plate to locate the spot. A yellow (or) brown color spots immediately formed indicates the distance traveled by the components from loading point. Detection can be done by using iodine chamber or UV detector.
Note: If the spot remains at a loading point or mobility is unsatisfactory / separation of the components is unsatisfactory, increase the polarity of solvent or solvent mixture in following order.
Petroleum ether / benzene / chloroform / ethyl acetate / acetone / methyl alcohol / acetic acid / water.
Result:
The number of components present in the given mixture------
On hit and trial basis the suitable solvent system selected, for better resolution of components is ------
푅푓 of component 1 and component 2 are ------respectively.
Department of Chemistry, RBVRRWC 159 2017-2018
Solvent Front Solvent front
Reactant Reactant
Product
Spot of reaction Loading point mixture
At zero minutes At time intervals
Solvent front Solvent front
Reactant
Product Product
Loading point Loading point
At time intervals At completion of reaction
Department of Chemistry, RBVRRWC 160 2017-2018
THIN LAYER CHROMATOGRAPHY – III
Aim: To monitor the chemical reaction by means of TLC Principle: Thin layer chromatography is mainly an adsorption chromatography technique. The compound spotted on thin layer of silica gel coated on a glass plate gets adsorbed onto the thin layers (stationary phase) & gets partitioned between the thin layers and mobile phase, when the mobile phase percolates through the thin layer. The percolation of mobile phase is by means of capillary forces. As adsorption and partition go on simultaneously, the compound will move along the mobile phase. In order to monitor the chemical reaction, as the chemical reaction progresses, at different time intervals, a small quantity of the reaction mixture and original reactant solution are to be spotted on TLC plates to be developed and detected.
Procedure: Part-I: Preparation of Slurry: Prepare a solvent containing CHCl3 and CH3OH in 2:1 ratio (66mL of CHCl3 and 33mL of CH3OH). Weigh 35gms of silica gel-G of TLC grade, transfer it into a bottle, and then add the prepared solvent system. Shake well and observe that uniform silica slurry is obtained.
Part-II: Preparation of TLC Plates: Dip two clean and dry TLC plates together in the slurry carefully and remove carefully. A uniform layer of silica gel-G gets adsorbed on plates along with little solvent. Allow the solvent to evaporate by keeping the slides aside for few minutes. Part-III: Monitoring the Reaction: Select the suitable solvent system to run the chromatogram for the reactant solution. Set up the reaction. As the chemical reaction progresses, at different time intervals, take out a small quantity of reaction mixture using a micro capillary tube, dilute it with chloroform and spot on the TLC plate. Along side this spot, spot the reactant solution. Develop the TLC plate in the solvent system selected and detect the spots. Synthesis of Acetanilide can be selected for this purpose. Result:
In the earlier stages of the reaction, one observes spots in the reaction mixture due to the reactant & the product, while in the later stages of the reaction the TLC of the reaction mixture shows only the product spot.
Department of Chemistry, RBVRRWC 161 2017-2018
COLUMN CHROMATOGRAPHY – I
Aim: To purify the given commercial anthracene containing carbazole and naphthacene sample by column chromatography.
Principle: In column chromatography, the stationary phase is a finely divided, porous solid while the mobile phase is an organic solvent or solvent mixture. The impure sample to be purified is applied as a small band at the front end of the column stationary phase. The compound gets adsorbed to the stationary phase and the different impurities in the compound adsorb with different strengths. Now the mobile phase is introduced. Then the sample will distribute between two phases till equilibrium is attained according to the value of its distribution coefficient (k= 퐶푠 / 퐶푚 ). Having been distributed between the two phases, the sample present in the mobile phase will be moved further down the column, where it will meet fresh stationary phase. The sample will again move from the mobile phase into the stationary phase when equilibrium will again be achieved (this process is called as sorption). Because the concentration of the sample in the mobile phase in the first section has been reduced, sample will move from the stationary phase back into the mobile phase (this process is called as desorption) in order to keep the value of distribution coefficient constant. In a very short time the entire sample will have desorbed from the stationary phase in the first section of the column and will be swept into the second section of the column by the mobile phase. Eventually, equilibrium will again be established and the sample will be found completely in the second section of the column. This process of sorption and desorption will continue until the sample reaches the end of the column, or is eluted from the column.
Materials Needed: Chromatography column (3cm internal diameter, 30cm length), Silica gel (column grade, 200 mesh), conical flasks, cotton, TLC micro slides (for checking the purity of anthracene)
Procedure: (Dry Packing Method): Clean the column with chromic acid mixture. Rinse with distilled water and dry it. Insert a cotton wool plug at the constricted end of the column. Introduce silica gel and press it down gently but firmly by dropping a glass pestle (made from solid glass rod 60cm x 7-8mm and flattened at one end to 10-12mm) onto it several times from a height of 5- 10cms. Repeat the process using 3-4cms portions of silica gel until a column 20 cm in length is obtained. Moisten the column by running in 25mL of n- hexane (or petroleum ether) from the dropping funnel. The column must be kept covered with solvent to a depth of about 5cm, throughout the experiment
Department of Chemistry, RBVRRWC 162 2017-2018
to avoid the formation of air bubbles. Load the technical sample of anthracene as discrete plug by adsorbing it over silicagel. Then insert a further small loose plug of cotton over the sample. Develop the chromatogram with 200mL of n-hexane/ pet ether. After a time three bands will be seen. a. Top – a narrow blue fluorescent band (carbazole) b. Middle – a yellow non – fluorescent band (naphthacene) c. Bottom – a broad blue violet fluorescent band (anthracene) Continue the development with 75mL of n-hexane/pet ether. Change the receiver when fluorescent material commences to pass into the eluate. Stop the elution when the naphthacene band almost reaches the cotton wool plug. Distill off the solvent from the eluate. Pure anthracene (M.P. 21 50 C) visibly fluorescent in daylight will be obtained. Check for the purity by means of TLC using UV detecton.
Wet Packing Method: Clean the column with chromic acid. Rinse with distilled water and dry it. Loosely plug the bottom end of the column with a small piece of cotton using a glass rod. Fill the column with petroleum ether to half level. Prepare uniform slurry of 75gms of silica gel in about 400mL of n-hexane/petroleum ether. Carefully transfer the slurry into the column with the stopcock slightly open. The slurry slowly settles down. Drain out any excess petroleum ether. When all the hexane/petroleum ether is drained out and the slurry level in the column is unchanged, close the stopcock. The packed column height should be 2/3rd of the length of the column. Load the technical sample of anthracene as discrete plug by adsorbing it over silicagel. Then insert a further small loose plug of cotton over the sample. Develop the chromatogram with 200mL of pet.ether. After a time three bands will be seen.
a. Top – a narrow blue fluorescent band (carbazole) b. Middle – a yellow non-fluorescent band (naphthacene) c.Bottom – a broad blue violet fluorescent band (anthracene) Continue the development with 75mL of n-hexane / pet ether. Change the receiver when fluorescent material commences to pass into the eluate. Stop the elution when the naphthacene band almost reaches the cotton wool plug distill off the solvent from the eluate. Pure anthracene (M.P. 2150C) visibly fluorescent in daylight will be obtained. Check for the purity by means of TLC using UV detection. Note: TLC of the commercial sample should be checked using UV detection to ensure that any impurities (carbazole and naphthacene) are present.
Department of Chemistry, RBVRRWC 163 2017-2018
COLUMN CHROMATOGRAPHY – II Aim: To separate o-nitro aniline and p-nitro aniline in the given mixture Principle: In column chromatography, the stationary phase is a finely divided, porous solid while the mobile phase is an organic solvent or solvent mixture. First the mixture to be separated into its constituents is applied as small band at the front end of the column stationary phase. The compounds in the mixture get adsorbed to the stationary phase particle surface and the different compounds adsorb with different strengths. Now the mobile phase is introduced. Then the sample will distribute between two phases till equilibrium is attained according to the value of its distribution coefficient (k=퐶푠 /퐶푚 ). Having been distributed between the two phases, the sample present in the mobile phase will be moved further down the column, where it will meet fresh stationary phase. The sample will again move from the mobile phase into the stationary phase (this process is called as sorption) when equilibrium will again be achieved. Because the concentration of the sample in the mobile phase in the first section has been reduced, sample will move from the stationary phase back into the mobile phase (this process is called as desorption) in order to keep the value of distribution coefficient constant. In a very short time the entire sample will have desorbed from the stationary phase in the first section of the column and will be swept into the second section of the column by the mobile phase. Eventually, equilibrium will again be established and the sample will be found completely in the second section of the column. This process of sorption and desorption will continue until the sample reaches the end of the column, or is eluted from the column. The rate of migration of a component is inversely proportional to its distribution coefficient (푅푚 훼 1/k) and the components of mixture will be separated only if they have different distribution coefficients between the stationary and the mobile phases and so differential rates of migration. Materials Needed: Chromatography column (3cm internal diameter, 30cm length), Sillica gel (column grade, 200 mesh, 200gms), conical flasks, mixture of o-nitro aniline and p-nitro aniline (100mg each) cotton, TLC micro slides (for monitoring the column chromatography separation).
Procedure:
(Dry Packing Method): Clean the column with chromic acid mixture. Rinse with distilled water and dry it. Insert a cotton wool plug at the constricted end of the column. Introduce silica gel and press it down gently but firmly by dropping a glass pestle (made from solid glass rod 60cm x 7-8mm and flattened at one end to 10-12mm) onto it several times from a height of 5- 10cms. Repeat the process using 3-4cms portions of silica gel until a column
Department of Chemistry, RBVRRWC 164 2017-2018
20 cm in length is obtained. Now, clamp the column vertically and carefully, moisten the column by running in 25mL of benzene / chloroform from the dropping funnel; the column must be kept covered with solvent to a depth of about 5cm, throughout the experiment to avoid the formation of air bubbles. Load the mixture of o-nitro aniline and p-nitro aniline as discrete plug by adsorbing it over silicagel. Then insert a further small loose plug of cotton over the sample. Open the stopper and fill the column with the benzene/chloroform. Feed the solvent continuously from the top. Initially, an orange band appears at the top of the column. After 30 minutes two bands – a clear orange band (due to o-nitro aniline) moving faster than the pale yellow band (due to p-nitro aniline) with a white gap in between them appear. Collect the column eluate in serially labelled conical flasks. In each conical flask collect about 150mL of eluate. Concentrate these fractions separately to a small volume. Examine their TLC. Combine the fractions that show the same TLC behaviour and evaporate the solvent to get pure o-nitro aniline and p-nitro aniline. Wet Packing Method: Clean the column with chromic acid. Rinse with distilled water and dry it. Loosely plug the bottom end of the column with a small piece of cotton using a glass rod. Fill the column with petroleum ether to half level. Prepare uniform slurry of 75gms of silica gel in about 400mL of benzene/ chloroform. Carefully transfer the slurry into the column with the stopcock slightly open. The slurry slowly settles down. Drain out any excess solvent. When all the solvent is drained out and the slurry level in the column is unchanged, close the stopcock. The packed column height should be 2/3 of the length of the column. Now, clamp the column vertically and carefully. Load the mixture of o-nitro aniline and p-nitro aniline as discrete plug by adsorbing it over silica gel. Now, clamp the column vertically and carefully. Moisten the column by running in 25mL of benzene / chloroform from the dropping funnel; the column must be kept covered with solvent to a depth of about 5cm throughout the experiment to avoid the formation of air bubbles. Load the mixture of o-nitro aniline and p-nitro aniline as discrete plug by adsorbing it over silicagel. Then insert a further small loose plug of cotton over the sample. Open the stopper and fill the column with the benzene/ chloroform. Feed the solvent continuously from the top. Initially, an orange band appears at the top of the column. After 30 minutes two bands – a clear orange band (due to o-nitro aniline) moving faster than the pale yellow band (due to p-nitro aniline) with a white gap in between them appear. Collect the column eluate in serially labelled conical flasks. In each conical flask collect about 150mL of eluate. Concentrate these fractions separately to a small volume. Examine their TLC
Department of Chemistry, RBVRRWC 165 2017-2018
Combine the fractions that show the same TLC behaviour and evaporate the solvent to get pure o-nitro aniline and p-nitro aniline. Then insert a further small loose plug of cotton over the sample. Open the stopper and fill the column with the benzene/chloroform. Feed the solvent continuously from the top. Initially, an orange band appears at the top of the column.
Department of Chemistry, RBVRRWC 166 2017-2018
ESTIMATION OF DRUGS
Department of Chemistry, RBVRRWC 167 2017-2018
Department of Chemistry, RBVRRWC 168 2017-2018
CONTENTS
1. ASSAY OF ASPIRIN
2. ASSAY OF IBUPROFEN
3. ASSAY OF ANALGIN
4. ASSAY OF ASCORBIC ACID
5. DETERMINATION OF CHLORIDE IN RINGER LACTATE SOLUTION
6. DETERMINATION OF CALCIUM IONS IN CALCIUM GLUCONATE INJECTION.
7. ASSAY OF RIBOFLAVIN
Department of Chemistry, RBVRRWC 169 2017-2018
Department of Chemistry, RBVRRWC 170 2017-2018
ASSAY OF ASPIRIN
Aim: To estimate the amount of aspirin present in the given aspirin tablets. Chemicals Name: Acetyl salicylic acid
Molecular Formula: C9H8O4 Structure:
Therapeutic uses:Analgesic, Antipyretic, Anti- rheumatic.
Dose: Analgesic, Antipyretic- 0.6 gms, 4-6 times per day, Antirheumatic- 0.1gm, 4-6 times a day upto 10 gms.
Usual strength: 0.15gms, 0.3gm, 0.5gm, 0.6gms.
Standards:Aspirin tablets contain not less than 95.0% and not more than 105.0% of the state amount of aspirin - C9H8O4
Principle: Aspirin can be determined by a method of back titration with blank determination.Determinations involving back titrations consist in the addition of excess of a standard volumetric solution to a weighed amount of sample, and determination of the excess not required by the sample. In general blank determinations are used if the volumetric solution is unstable and if alters in strength during assay. It is necessary to perform blank determinations in assays which involve heating a liquid containing excess of standard alkali in an apparent change in strength if certain indicators are used. This may be due to interaction of the reagent with the glass to the absorption of atmospheric carbondioxide. The amount of change will be dependent upon the conditions used. In effect the alkali must be standardized under the conditions to be usedin the determinations. This is called a blank determination. Determination of percent of aspirin depends upon the reactions expressed by the following equations.
Department of Chemistry, RBVRRWC 171 2017-2018
CH3.COOC6H4.COOH + 2NaOH CH3.COONa + C6H4 (OH) COONa
CH3.COO C6H4.COOH = 2NaOH = 2H=2000 mLof 1NNaOH
∴ 180.1gms of C9H8O4= 2000 mLof 1N NaOH
∴ 0.04504gms of C9H8O4= 1 mL of 0.5 N NaOH
Chemicals: Aspirin tablets, Solid Na2CO3, 0.5 N NaOH, 0.5N HCl, Methyl orange and Phenolphthalein indicators.
Apparatus: Burette, Pipette, Conical flask.
PROCEDURE:
STEP I: Preparation of standard Na2CO3 Solution: Weigh accurately about 2.65gms of Na2CO3 into a 100mL standard flask. Dissolve it in minimum quantity of distilled water. Then make it up to the mark. Shake well for uniform concentration.
STEP II: Standardization of HCl solution:Clean the burette, rinse with distilled water and then rinse with given HCl solution. Fill the burette with the given HCl solution and clamp it to the stand. Pipette out 20mL of prepared Na2CO3 solution into a clean conical flask. Add 20mL of distilled water to it. Add 1 to 2 drops of methyl orange and titrate the solution with HCl taken in the burette until the colour changes from yellow to orange. Repeat the titrations for concurrent readings.
Department of Chemistry, RBVRRWC 172 2017-2018
STEP III: Standardization of NaOH solution (Blank determination): Fill the burette with HCl. Pipette out 20mL of given sodium hydroxide solution into a clean conical flask. Add 20mL of distilled water. Boil gently for ten minutes. Add 1-2 drops of phenolphthalein. Titrate it against standardized HCl taken in the burette until the colour changes from pink to colourless. Repeat the titrations until the concurrent readings are obtained.
STEP IV: Assay of aspirin: Weigh and powder 20 tablets. Weigh accurately a quantity of powder equivalent to about 0.15gms of aspirin into a clean conical flask. Add 20mL of NaOH and 20mL of distilled water. Boil gently for 10 min and titrate the excess of NaOH with HCl using phenolphthalein indicator.
Each mL of 0.5N NaOH is equivalent to 0.04054gms of C9H8O4
RESULT: The percentage of aspirin has been calculated as ------
Department of Chemistry, RBVRRWC 173 2017-2018
CALCULATIONS:
Step I: Preparation of standard Na2CO3solution:
Weight of the empty weighing bottle W1 =
Weight of bottle with Na2CO3 W2 =
Weight of bottle after transferring Na2CO3 W3 =
Weight of Na2CO3 taken W2-W3=
Normality of Na2CO3 solution = Weight X 1000 = N1 Equivalent weight (53) X 100 Step II:Standardization of HCl Solution:
Na2CO3+ 2HCl 2NaCl + H2O+ CO2 S. No Volume of Burette reading Volume of HCl run
Na2CO3 Initial Final down
N Na2CO3X VNa2CO3 = NHClX VHCl
NHCl= N Na2CO3 X V Na2CO3 = N2
VHCl Step III: Standardization of NaOH solution (Blank determination):
NaOH + HCl NaCl + H2O S. No Volume of Burette reading Volume of HCl run down NaOH Initial Final (xmL)
Department of Chemistry, RBVRRWC 174 2017-2018
N NaOHX VNaOH = N HClX VHCl
N NaOH = N HClX VHCl=N3
V NaOH
Step IV: Assay of aspirin:
S. No. 1 2 3 4 5 6 7 8 9 10
Wt. of tablets
Total wt. of tablets = Average wt. of tablets = Weight of powder equivalent to 0.15gms of aspirin =
S. No. Burette reading Volume of HCl run down Initial Final (y mL)
xmL of HCl required for the neutralization of 20 mL of NaOH ymL of HCl required for the neutralization of ? mL of NaOH
= y X20mL = z mL x
Department of Chemistry, RBVRRWC 175 2017-2018
Volume of NaOH remained = z mL Volume of NaOH used for hydrolysis of aspirin = 20mL –z mL 1mL of 0.5 N NaOH is equivalent to 0.04054 gm of Aspirin
1mL of N3NaOH is equivalent to?gm of Aspirin
= N3 X 0.04054 = a gms 0.5
Amount of Aspirin present = (20 – z) X a = b gms
% purity = b X 100 0.15
Department of Chemistry, RBVRRWC 176 2017-2018
ASSAY OF IBUPROFEN
Aim: To determine the amount of Ibuprofen present in the given ibuprofen tablets. Chemical Name: (RS) 2-(4- isobutyl phenyl)-propionic acid.
Molecular Formula:C13H18O2 Structure:
Therapeutic uses: Anti inflammatory and analgesic. Dose:Ibuprofen-0.6 to 1.2 gm daily in divided doses. Usual strength:0.2gms.
Standards: Ibuprofen tablets contains not less than 95.5% and not more than 105% ofC13H18O2
Principle: Ibuprofen is acidic in nature. The amount of ibuprofen can be estimated from the tablets by extracting the active ingredient into chloroform and preparing an appropriate solution of Ibuprofen and titrating with NaOH using phenolphthalein as indicator.
206.28gmsofC13H18O2 = 1000mL of 1 N NaOH
0.20628gms of C13H18O2 = 1mL of 1 N NaOH
0.020628gms of C13H18O2= 1mL of 0.1 N NaOH
Department of Chemistry, RBVRRWC 177 2017-2018
Apparatus Required:Burette, pipette, conical flask.
Chemicals Required: Ibuprofen tablets, solid Na2CO3, 0.1N HCl, methyl orange, 0.1N NaOH, phenolphthalein, chloroform, 95% ethanol.
PROCEDURE:
Step I: Preparation of standard 0.1N Na2CO3solution: Weigh accurately about 0.53gms of Na2CO3into a 100mL standard flask. Dissolve it in minimum quantity of distilled water. Then make it up to the mark. Shake well for uniform concentration.
Step II: Standardization of HCl Solution:Fill the cleaned burette with the given HCl solution. Pipette out 20mL of prepared Na2CO3 solution into a clean conical flask. Add 20mL of distilled water to it. Add 1 drop of methyl orange and titrate the solution with HCl taken in the burette until the colour changes from yellow to orange. Repeat the titrations for concurrent readings.
Step III: Standardization of NaOH solution: Fill the Burette with HCl. Pipette out 20mL of given sodium hydroxide solution into a clean conical flask. Add 20mL of distilled water. Add 1-2 drops of phenolphthalein. Titrate it against standardized HCl taken in the burette until the solution becomes colourless. Repeat the titrations until the concurrent readings are obtained.
Step IV: Estimation of Ibuprofen: Weigh&powder 20 tablets. Weigh accurately a quantity of powder equivalent to 0.4gm of Ibuprofen. Extract with 30mL of chloroform for 15 min and filter. Wash the residue with 2 quantities each of 10mL of chloroform. Add the washing to the filtrate. Gently evaporate the filtrate just to dryness in a current of air. Dissolve the residue in 10 mL of 95% ethanol previously neutralized to phenolphthalein solution and titrate with standardized NaOH solution using Phenolphthalein as indicator ( Colourless to pink)
Department of Chemistry, RBVRRWC 178 2017-2018
Each mL of 0.1 N NaOH is equivalent to 0.02068gms of Ibuprofen
RESULT: The percentage amount of Ibuprofen has been calculated as--
CALCULATIONS:
Step I: Preparation of standard Na2CO3 solution:
Weight of the empty weighing bottle W1 =
Weight of bottle with Na2CO3 W2 =
Weight of bottle after transferring Na2CO3 W3 =
Weight of Na2CO3 taken W2-W3=
Normality of Na2CO3 solution= Weight X 1000 = N1 Equivalent weight X 100
Step II:Standardization of HCl Solution:
Na2CO3+ 2HCl 2NaCl + H2O + CO2 S. No Volume of Burette reading Volume of HCl run
Na2CO3 Initial Final down (x mL)
N Na2CO3X V Na2CO3 = N HClXVHCl
NHCl = N Na2CO3 X V Na2CO3 = N2
VHCl
Department of Chemistry, RBVRRWC 179 2017-2018
Step-III : Standardization Of NaOH solution:
S. No Volume of Burette reading Volume of HCl run down NaOH Initial Final (x mL)
N NaOH X V NaOH = N HCl X V HCl
N NaOH = N HClX VHCl = N3
V NaOH
Step IV: Estimation of Ibuprofen:
S. No. 1 2 3 4 5 6 7 8 9 10 Wt. of tablets
Total wt. of tablets = Average wt. of tablets = Weight of powder equivalent to 0.4gms of Ibuprofen =
Department of Chemistry, RBVRRWC 180 2017-2018
S. No. Burette reading Volume of NaOH run Calibrated Values Initial Final down (y mL) y mL
1 mL of 0.1 N NaOH is equivalent to 0.02068gm of Ibuprofen
1 mL of N3NaOH is equivalent to?gm ofIbuprofen
= N3X 0.02068 = a gms 0.1 Amount of Ibuprofen present = a X y mL= b gms
% purity = b X 100 0.4
Department of Chemistry, RBVRRWC 181 2017-2018
ASSAY OF ANALGIN
Aim: To estimate the amount and percentage purity of analgin in the given analgin tablets.
Chemical Name: [(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4- yl)methylamino] methanesulfonic acid
Molecular Formula: C13H16 N3NaO4S. H2O
Therapeutic uses: Analgesic.
Dose: Analgin- 0.5 to 3gm daily in divided doses.
Standards: Analgin tablets contains not less than 95% and not more than 105.0% of the stated amount of analgin. Principle: Analgin is also called metamizole. It can be estimated by extracting the active ingredient into alcohol and titrating against standard iodine solution. It is a redox titration in which iodine acts as a self indicator.
Department of Chemistry, RBVRRWC 182 2017-2018
351.4gmsof C13H16N3NaO4S. H2O = 2000 mL of 1N I2
175.7gmsofC13H16 N3NaO4S. H2O = 1000 mL of 1N I2
0.1757gmsofC13H16 N3NaO4S. H2O = 1 mL of 1N I2
0.01757gmsofC13H16 N3NaO4S. H2O = 1 mL of 0.1N I2
Apparatus Required: Burette, pipette, iodination flask and conical flask.
Chemicals Required: Analgintablets, solid potassium dichromate, 0.1 N hypo solution, 0.1N iodine solution, Solid KI, dil. sulphuric acid, starch indicator.
Procedure: Step- I: Preparation of standard potassium dichromate solution: Weigh accurately about 0.488gm of potassium dichromate and transfer it into a 100mL standard flask. Dissolve in minimum amount of distilled water and make it up to the mark with distilled water.
Department of Chemistry, RBVRRWC 183 2017-2018
Step - II: Standardization of Hypo solution: Pipette out 20mL of the prepared potassium dichromate solution into a clean iodination flask and add a test tube full of dil.sulphuric acid and 1gm of solid KI. Shake the solution and put the lid. Keep it in dark for 15min. Then take out from dark and wash the bottom of lid with distilled water such that washings will fall into the flask.Titrate this solution against hypo solution taken in the burette till a straw yellow colour appears. Then add 1mL of starch solution to this solution where by a blue colour develops. Continue the titration until the blue colour changes to green. Repeat the titrations for concurrent readings.
Step - III: Standardization of Iodine solution:Take 20mL of iodine solution from the burette into a 250mL conical flask and titrate against hypo solution until the colour changes to pale yellow. Then add 1mL of starch solution and continue the titration until the blue color changes to colourless. Repeat the titrations for concurrent readings.
Step - IV: Assay of Analgin: Weight and powder 20 tablets. Weigh accurately a quantity of the powder equivalent to 0.5gm of analgin into 100mL volumetric flask. Add 10mL of distilled water and shake well for 1 min. Dilute it up to the mark with alcohol, shake well and filter. Take 20mL of the filtrate and titrate it with standard Iodine solution until yellow colour appears which is stable for 30 seconds.
Each 1mL of 0.1N Iodine = 0.01757gm of Analgin
Result: The amount of analgin present in the given sample is ----- and the percentage purity of given analgin tablet is -----
Department of Chemistry, RBVRRWC 184 2017-2018
CALCULATIONS: PART – I: Preparation of standard potassium dichromate solution:
Weight of the empty weighing bottle W1 =
Weight of bottle with K2Cr2O7 W2 =
Weight of bottle after transferring K2Cr2O7 W3 =
Weight of K2Cr2O7 taken W2-W3=
Normality of potassium dichromate = Weight of K2Cr2O7 X 1000 = N1 Equivalent weight X 100
PART – II: Standardization of Hypo Solution: 2- 2- + 3+ 2- Cr2O7 + 6S2O3 + 14H 2 Cr + 3S4O6 + 7H2O S. No Volume of Burette reading Volume of Hypo run
K2Cr2O7 Initial Final down
N K2Cr2O7 X V K2Cr2O7 = N Hypo X V Hypo
N Hypo = N K2Cr2O7 X V K2Cr2O7 = N2
V Hypo
PART III: Standardization of NaOH solution: 2- - 2- I2 + 2S2O3 2I + S4O6
S. No Volume of Burette reading Volume of hypo run down Iodine Initial Final (xmL)
Department of Chemistry, RBVRRWC 185 2017-2018
N IodineX VIodine = N Hypo X V Hypo
N Iodine = N Hypo X V Hypo = N3
V Iodine
PART IV: Assay of Analgin:
S. No. 1 2 3 4 5 6 7 8 9 10 Wt. of tablets
Total wt. of tablets = Average wt. of tablets = Weight of powder equivalent to 0.5gms of analgin =
S. No. Burette reading Volume of Iodine run down Initial Final (x mL)
Volume of Iodine consumed by analgin = x mL 1 mL of 0.1 N iodine = 0.01757gms of analgin
1 mL of N3 iodine = 0.01757 X N3 = a gms 0.1 Amount of analgin present in 20mL = a X x mL = b gms Amount of analgin present in 100mL=amount of analgin present in the powder equivalent to 0.5 = b X 5 = c gms % purity of analgin = c X 100 0.5
Department of Chemistry, RBVRRWC 186 2017-2018
ASSAY OF ASCORBIC ACID
Aim: To estimate the amount and percentage purity of the ascorbic acid in the sample.
Chemical Name: (R)-5-[(S)-1, 2-dihydroxy-ethyl)-3, 4-dihydroxy -5(H)- furan-2-one
Molecular Formula:C6H8O6
Structure:
Therapeutic uses: Vitamin (antiscorbutic)
Dose:In the prevention of scurvy, 25-75mg daily in the treatment of scurvy not less than 250mg daily in divided doses.
Standards:Ascorbic acid is the enolic form of 1-gulofuranolactone. It contains not less than 90% and not more than 100.5% of C6H8O6
Principle:The determination depends upon the quantitative oxidation of ascorbic acid also known as Vitamin ‘C’ to dehydro ascorbic acid with standard iodine solution. It is a redox titration where iodine acts as a self indicator.
Department of Chemistry, RBVRRWC 187 2017-2018
C6H8O6= I2 = 2electrons
∴ 176.12gms of C6H8O6 = 2000 mL 1N I2
∴ 0.08806gms of C6H8O6 = 1mL 1N I2
∴ 0.008806gms ofC6H8O6 = 1mL 0.1 N I2
Apparatus Required: Burette, pipette, iodination flask and conical flask
Chemicals Required: Ascorbic acid powder, solid potassium dichromate, 0.1N hypo solution, 0.1N iodine solution, solid KI, dil.sulphuric acid, starch indicator
Procedure: Step – I: Preparation of standard potassium dichromate solution: Weigh accurately about 0.488gm of potassium dichromate and transfer it into a 100mL standard flask. Dissolve in minimum amount of distilled water and make it up to the mark with distilled water.
Step – II: Standardization of Hypo solution: Pipette out 20mL of the prepared potassium dichromate solution into a clean iodination flask and add a test tube full of dil.sulphuric acid and 1gm of solid KI. Shake the solution and put the lid. Keep it in dark for 15min. Then take out from dark and wash the bottom of lid with distilled water such that washings will fall into the flask. Titrate this solution against hypo solution taken in the burette till a straw
Department of Chemistry, RBVRRWC 188 2017-2018
yellow colour appears. Then add 1mL of starch solution to this solution where by a blue colour develops. Continue the titration until the blue colour changes to green. Repeat the titrations for concurrent readings.
Step – III: Standardization of Iodine solution:Take 20mL of iodine solution from the burette into a 250mL conical flask and titrate against hypo solution until the colour changes to pale yellow. Then add 1mL of starch solution and continue the titration until the blue colour changes to colourless. Repeat the titrations for concurrent readings.
Step – IV: Assay of Ascorbic acid: Weigh accurately 0.1gm of Ascorbic acid into 250mL conical flask. Dissolve it in a mixture of 100mL of freshly boiled and cooled water and immediately titrate the mixture with standard iodine solution taken in the burette solution until yellow colour appears which is stable for 30 seconds.
Each 1mL of 0.1N Iodine = 0.008806gm of Ascorbic acid.
Result: The amount of Ascorbic acid present in the given sample is --- and the percentage purity of Ascorbic acid is ------
CALCULATIONS: Step – I: Preparation of standard potassium dichromate solution:
Weight of the empty weighing bottle W1 =
Weight of bottle with K2Cr2O7 W2 =
Weight of bottle after transferring K2Cr2O7 W3 =
Weight of K2Cr2O7 taken W2-W3=
Normality of potassium dichromate = Weight of K2Cr2O7 X 1000 = N1 Equivalent weight(49) X100
Department of Chemistry, RBVRRWC 189 2017-2018
Step– II: Standardization of Hypo Solution:
2- 2− + 3+ 2− Cr2O7 +6S2O3 + 14H 2Cr + 3S4O6 + 7H2O S. Volume of Burette reading Volume of Hypo run
No K2Cr2O7 Initial Final down
NK2Cr2O7 X VK2Cr2O7= N HYPOX VHYPO
N HYPO = N K2Cr2O7 X V K2Cr2O7 = N2
VHYPO
Step- III: Standardization of Iodine solution:
2- − 2- I2+ 2S2O3 2I + S4O6
S. Volume of Burette reading Volume of hypo Run No Iodine Initial Final down
N IodineX VIodine = N HypoX V Hypo
N Iodine= N HypoX VHypo = N3
V Iodine
Department of Chemistry, RBVRRWC 190 2017-2018
Step- IV: Assay of Ascorbic acid:
S. No. Burette reading Volume of Iodine run down (x) Initial final
Volume of Iodine required by ascorbic acid = x mL
1 mL of 0.1N iodine = 0.008806 gms of ascorbic acid
1 mL of N3Iodine = 0.008806 X N3 iodine = a gms
0.1 Amount of ascorbic acid present = a X x = b gms % purity of ascorbic acid = b X 100 0.1
Department of Chemistry, RBVRRWC 191 2017-2018
DETERMINATION OF CHLORIDE IN RINGER LACTATE SOLUTION FOR INJECTION Aim: To determine the amount of chloride in ringer lactate solution for Injection.
Chemical composition: Each 10mL ringer solution contains 3 electrolytes NaCl-0.60gms, KCl-0.04gms, CaCl2- 0.027gms & total of 0.667gms of total chloride present
Therapecutic uses: Fluid and electrolyte replenisher
Standards: Compound sodium chloride injection contains not less than 0.37% and not more than 0.42% w/v of total chloride and not less than 0.025% w/v and not more than 0.029% w/v of CaCl2.2H2O and more than 0.23% w/v and not more than 0.28% w/v of lactic acid C3H6O3. It contains no antimicrobial agents.
Principle:If a known quantity of ringer lactate solution is treated with a known excess of AgNO3solution we get the corresponding amount of AgCl. The excess of unreacted AgNO3 will be determined by titrating with standard solution of ammonium thiocyanate. The volume of NH4SCN consumed in the titration corresponding to the amount of AgNO3left of unreacted (say ‘y’ mL) in the similar manner. A blank titration is performed with 20mL of AgNO3with NH4SCN (say ‘x’ mL). The amount of AgNO3 needed to precipitate chloride ions as silver chloride is equal to (x-Y)mL, then by calculation the amount of chloride will be determined - - AgNO3 + Cl NO3 +AgCl
AgNO3 + NH4SCN NH4NO3+ AgSCN
3+ Fe + 3NH4SCN Fe (SCN)3
- 169.89gms of AgNO3 = 35.463gms of Cl
- 1000mL 1N AgNO3= 35.463gms of Cl
- 1mL 0.1N AgNO3= 0.00335463gms of Cl
Apparatus Required: Burette, pipette and conical flask
Department of Chemistry, RBVRRWC 192 2017-2018
Chemicals Required: Ringers lactate solution, NaCl, Solid silver nitrate, 0.1N ammonium thiocyanate solution, conc. nitric acid, K2CrO4, nitro benzene and ferric ammonium sulphate indicator. Procedure: Step-I: Preparation of standard 0.1N NaCl solution: Weigh accurately about 0.58 gm of pure NaCl and transfer it into a 100mL standard flask. Dissolve in minimum amount of distilled water and make it up to the mark with distilled water.Shake well for uniform concentration.
Step–II: Standardization of AgNO3 solution: Pipette out 20 mL of 0.1N NaCl solution into a clean conical flask. Add 1mL of K2CrO4 indicator. After addition of K2CrO4 a red colour precipitate appear in solution temporarily, but this colour disappears after shaking. The contents at the end point, silver chromate which is going to be formed remains permanently red colour in the solution. Note the AgNO3 consumed in the titration.
Step-III: Standardization of NH4SCN solution: Pipette out 20 mL of 0.1N AgNO3 into a clean conical flask, add 1.5mL of conc. HNO3, 2mL of nitrobenzene & 1mL of ferric ammonium sulphate. Shake well and titrate with NH4SCN solution until the colour becomes reddish yellow. Repeat the titration for concurrent readings. Step-IV: Estimation of chloride ions: Pipette out 10mL of ringer solution into a clean conical flask containing 20mL of water. To this add 20mL of 0.1N silver nitrate by means of a pipette. Then add 1.5mL of nitric acid, 2mL of nitro benzene and one mL of ferric ammonium sulphate solution. Shake well & titrate with ammonium thiocyanate until the colour becomes reddish yellow.
Each 1mL of 0.1N AgNO3 is equivalent to 0.0035463gms of chloride ions. Result: The percentage of purity of chloride ions in ringer lactate solution---
CALCULATIONS: Step – I: Preparation of standard silver nitrate solution:
Weight of the empty weighing bottle W1 =
Weight of bottle with NaCl W2 =
Weight of bottle after transferring NaCl W3 =
Weight of NaCl taken W2-W3=
Department of Chemistry, RBVRRWC 193 2017-2018
Normality ofNaCl = Weight of NaClX 1000 = 푁1 Equivalent weightX 100
Step – II: Standardization of AgNO3Solution (Blank titration):
AgNO3 + NaCl NaNO3+ AgCl
S. No Volume of Burette reading Volume of AgNO3 NaCl Initial final Run down (x)
NaCl AgNO3
N1=N1 N2=?
V1=20mL V2=x
Normality of AgNO3(N2) = N1 X V1
V2
Step-III: Standardization of NH4SCN solution:
AgNO3 + NH4SCN NH4NO3 + AgSCN
S. No Volume of Burette reading Volume of NH4SCN
AgNO3 Initial final Run down (x)
AgNO3 NH4SCN
N1=N1 N2=?
V1=20mL V2=x
Department of Chemistry, RBVRRWC 194 2017-2018
Normality of NH4SCN(N2) = N1 X V1
V2 Part IV: Estimation of Chloride ions: - - AgNO3 + Cl NO3 + AgCl
S. No. Volume of Burette reading Volume of NH4SCN
AgNO3+ Run down (y) Initial Final ringer lactate solution
xmL of NH4SCN required for the precipitation of 20 mL of AgNO3
ymL of NH4SCN required for the precipitation of ?mL of AgNO3 y X 20 mL = x ZzmL
Volume of AgNO3remained = z mL
Volume of AgNO3used for precipitation of chloride ions = 20mL – zmL
1mL of 0.1N AgNO3 is equivalent to 0.0035463gms of chloride ions
1mL of N2 AgNO3 is equivalent to?gms of chloride ions
N2 X 0.0035463 = a gms 0.1 Amount of chloride ions present = (20 – z) X a = b gms
% purity = b X 100 0.0393 Note: The stated amount of chloride ions present in 10mL of Ringers lactate solution is 0.0393gms.
Department of Chemistry, RBVRRWC 195 2017-2018
DETERMINATION OF CALCIUM IONS IN CALCIUM GLUCONATE INJECTION Aim:To determine the amount of calcium ions in calcium gluconate injection. Chemical Name: Calcium gluconate
Molecular Formula: C12H22CaO14.H20 Structure:
- O O
H OH HO H Ca+2. H O H OH 2 H OH
OH 2 Therapeutic uses: Calcium replenisher
Dose: Calcium gluconate by Intravenous or muscular injection- 1 to 2mL Usual Strength:One gram in 10mL.
Standards: Calcium gluconate is a sterile solution of Calcium gluconate in water for injection. Not more than 5% of Calcium gluconate may be replaced with suitable calcium salts as stabilizers. It contains a quantity of calcium equivalent to not less than 8.5% and not more than 9.4% of stated amount of Calcium gluconate.
Principle: Calcium ions can be determined by means of complexometric titration with EDTA. It comes under substitution type of complexometric titrations. Calcium ions will not give sharp end point with EBT indicator. In order to get sharp end point Mg+2 ions are also added. The stability order is:
Ca-EDTA > Mg-EDTA > Mg-EBT
So to calcium ions, magnesium ions are added in suitable pH conditions. The little amount of EBT forms Mg-EBT complex which is wine red in color. During titration EDTA reacts with Ca+2ions then with free Mg+2 ions and later replace the Mg+2 ions present in Mg-EBT complex leaving the free indicator. So at the end the colour of the solution is colour of indicator at that pH i.e. blue.
Department of Chemistry, RBVRRWC 196 2017-2018
Ca+2+ EDTA Ca-EDTA 40.08gms of Ca+2 = 1000mL 1.0 M EDTA 40.08gms of Ca+2 = 2000mL 0.05 M EDTA 0.002004gms of Ca+2 = 1mL 0.05 M EDTA
Apparatus Required:Burette, Pipette & conical Flask
Chemicals Required :Calcium gluconate injection, Solid MgSO4, 0.05M EDTA Solution, ammonical buffer PH – 10, EBT indicator.
Procedure:
Step-I:Preparation of Standard MgSO4 Solution: Weigh accurately about 1.254 gms of MgSO4into a clean 100mL volumetric flask.Dissolve in minimum quantity of distilled water. Make the solution upto the mark with distilled water.
Department of Chemistry, RBVRRWC 197 2017-2018
Step-II: Standardization of EDTA solution:Pipette out 10 mL of MgSO4into a clean conical flask, add 10mL water, 2mL of PH -10 buffer, warm to 400C. Add a pinch of EBT indicator. Then titrate with EDTA taken in the burette till the colour changes from wine red to blue. Repeat the titrations till the concurrent readings are obtained.
Step-III: Assay of Ca+2 ions: Pipette out 2.5mL of calcium gluconate injection into aclean conical flask. Add 10mL of MgSO4 solution and add 10mL of water, 2mL of PH -10 buffer. Add a pinch of EBT indicator.Then titrate with EDTA taken in the burette till the colour changes from wine red to blue. Each 1 mL of 0.05M EDTA is equivalent to 0.002004 gms of calcium ions.
Result: The percentage of calcium ions present in calcium gluconate is ------
CALCULATIONS:
PART – I: Preparation of standard MgSO4 solution:
Weight of the empty weighing bottle W1 =
Weight of bottle with MgSO4 W2 =
Weight of bottle after transferring MgSO4 W3 =
Weight of taken MgSO4 W2-W3=
Molarity of MgSO4 solution = Weight X 1000 = 푀1 Molecular weight X 100 PART – II:Standardization of EDTA Solution:
S. No Volume of Burette reading Volume of EDTA Run down
MgSO (x) 4 Initial final
M MgSO4 X VMgSO4 = M EDTAX VEDTA
M EDTA = MMgSO4 X VMgSO4 = 푀2
V EDTA
Department of Chemistry, RBVRRWC 198 2017-2018
Part-III: Assay of Ca2+ ions
S. No Burette Volume of EDTA Run Calibrated values reading down (y mL) Initial final
Volume of EDTA required for Ca2+ ions= Titre value - volume of EDTA required for Mg2+ ions = y-x=z mL
1mL of 0.05M EDTA is equivalent to 0.002004 gms of Calcium ions.
1mL of M2 EDTA is equivalent to ? gms of calcium ions
M2X 0.002004 = a gms 0.05 Amount of calcium ions present = axz= b gms
% of Ca2+ ions present = b X 100 0.25 Note: The stated amount of Calcium gluconate in 2.5mL of injection is
0.25gms. % of calcium ions should be expressed as % of stated amount of
Calcium gluconate.
Department of Chemistry, RBVRRWC 199 2017-2018
ASSAY OF RIBOFLAVIN
Aim: To determine the amount of riboflavin present in Riboflavin tablets by the use of UV-Vis Spectrophotometer.
Chemical Name: 3,10-dihydra-7,8-dimethyl-10-[(2S,3S,4R)-2,3,4,5- tetrahydroxypentyl] benzopteridine-2,4-dione.
Molecular Formula: C17H20N4O6
Structure:
Therapeutic use: Vitamin B group.
Dose: Prophylactic 1-4 mg daily, therapeutic 5-10 mg daily.
Standards: Not less than 98% and not more than 102% of stated amount of C17H20N4O6
Principle:Amount of Riboflavin can be estimated by UV-VIS Spectrophotometer by making use of standard absorptivity method. According to Beers Lambert Law the absorbance is directly proportional to concentration. After measuring the absorbance of appropriate dilute solution of Riboflavin at 454nm, concentration of test solution using standard absorptivity value (323) can be calculated.
A=A1%X b X C
C= A / A1% X b
Department of Chemistry, RBVRRWC 200 2017-2018
Where A = absorbance or optical density. A1% = specific molar absorbance at a particular wavelength (323) b = cell length=1cm C = concentration of riboflavin in gms/mL
Procedure: Powder 5 tablets and weigh the powder equivalent to about 30mg of riboflavin in a 250mL beaker. Add 1.5mL of glacial acetic acid and 25 mL of water, heat on a water bath for 1hr with occasional stirring and add 25mL of distilled water. Cool, then add 7.5mL of 1N NaOH solution with continuous stirring and add 100mL of distilled water. Transfer the solution with the help of funnel into a 250mL standard flask. Make it upto the mark, mix well and filter. Discard the first 1/5th portion of filtrate. Then collect the other remaining filtrate, mix well. Measure the absorbance at λ max at 454nm. Calculations:
S.No 1 2 3 4 5
Total weight =
Average weight = Amount of riboflavin = 0.03gms Optical density recorded (O.D) = C = O.D / A1% X b = y gms. ygms of riboflavin present in 100mL solution. ? ( Z value) of riboflavin present in 250mL solution 0.03 gms of riboflavin contains Z gms Average weight of riboflavin contains------? gms. Amount of riboflavin present in 250mL solution is ------% purity = Practical Value / theoretical value X 100 =
Department of Chemistry, RBVRRWC 201 2017-2018
MICROWAVE ASSISTED HYDROLYSIS OF BENZAMIDE
Aim:To perform Hydrolysis of benzamide by using Microwave Irradiation Technique.
Equation:
O OH H2N O
20%H2SO4 Microwave Assisted Synthesis
benzoic acid benzamide Principle:Microwave normally have wavelength between1cm & 1m, Frequency of 30 to 300 GHz. Microwave irradiation induces specific interactions between materials and waves of electromagnetic nature assimilated to dielectric heating.
In Electromagnetic spectrum the Microwave radiation is located between IR & Radiowave radiation.Telecommunication & MW radar equipment occurs in many of the band frequencies in this region. In order to avoid interference with these systems, the household &Industrial MW ovens operate at a fixed frequency of 2.4GHz. The energy = 0.3cal/Mole (from E=hν).
Chemicals:Benzamide-2gm
20%Sulphuric Acid- 10mL
Apparatus: Glass beaker, Glass rod
Principle:Microwave assisted synthesis.
Procedure:
A mixture of benzamide and 20 % sulphuric acid are taken in a 150 mL glass beakerand then placed in a microwave oven and heated for 10min. After cooling, the reaction mixture is made basic with dil. NaOH.A white coloured product of Benzoic acid is formed.The formed Benzoic acid was checked by its solubilty tests & Melting point,
Melting Point: 121-1230 C
Department of Chemistry, RBVRRWC 202 2017-2018
REFERENCES:
1. Practical Organic Chemistry by Mann and Saunders 2. Comprehensive Organic Chemistry by VK Ahluwalia and RenuAggarwal 3. Text book of Practical Organic Chemistry by Vogel 4. Elementary Practical Organic Chemistry by Arthur Vogel 5. Experimental Organic Chemistry by David Todd 6. Laboratory Method of Organic Chemistry by L. Gattermann 7. Laboratory Manual of Organic Chemistry by Raj K Bansal 8. Spectrometric Identification of Organic Compounds by Silverstein and Basselor 9. Organic Spectroscopy by William Kemp 10. Analytical Chemistry by GL David Krupadanam, D. Vijaya Prasad, K.VaraprasadRao, KLN Reddy &C.Sudhakar 11. Quantitative organic analysis by Vogel 12. Chromatographic separations-Wikipedia
Department of Chemistry, RBVRRWC 203 2017-2018