Aim: To prepare and submit 5,5-Diphenylhydantion from Benzil.
Apparatus:
- RBF
- Beaker
- Measuring Cylinder
- Reflux condeser
- Water bath
- Funnel
- Heating mantel
Chemicals Required:
- Benzil
- Urea
- Sodium Hydroxide
- Ethanol
- Hydrochloric Acid
Principle: The principle involved in this reaction is Pinacol-pinacolone rearrangement which is a method for converting a 1,2-diol to a carbonyl compound called Pinacol which later undergoes a rearrangement and dehydration to from a monoketone called Pinocolone. in this reaction aromatic diketone Benzil reacts with urea to form a pinacol. Latter this undergoes rearrangement to form pinacolone nothing but 5,5-Diphenylhydantion(Phenytoin).
Mechanism: This reaction mechanism involves the there steps.
- Protonation of 1,2-diol
- Generation of Carbonium ion by loss of water molecule.
- 1,2-shift of alkyl group to from a ketone.
Procedure: Place 5.3g(0.025mol) of benzil , 3.0 g of urea, 15ml of 30 percent aqueous sodium hydroxide solution and 75ml of ethanol in a 100ml round-bottomed flask. Attach a reflux condenser and boil under reflux using an electric heating mantle for at least 2hours. Cool to room temperature, pour the reaction product into 125ml of water and mix thoroughly. Allow to stand for 15minutes and then filter under suction to remove an insoluble by-product. Render the filtrate strongly acidic with concentrated hydrochloric acid, cool in ice-water and immediately filter off the precipitated product under suction.
Category: Anti-Epileptic.
Calculation:
Molecular Weight of Benzil=210g/mol.
Molecular weight of Phenytoin=252g/mol
210g of Benzil gives 252g of phenothazine
1g of diphenylamine gives =X g of phenothizine =1.2g
%yield = (practical yield/Theoritical yield)X100
Report: 5,5-Diphenyhydantionwas synthesized and the percentage yield was found nto be ____%
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