Category: Organic Preparation

Preparation of Osazone

Preparation of Osazone

To confirm the presence of carbohydrate during the analysis of an organic compound, the best way would be the preparation of osazone from the original organic compound given to you.

Osazone
Preparation of Osazone

Chemicals and Equipment’s

  • 0.5 grams of carbohydrates or sugar
  • 0.4 grams of phenyl hydrazibe hydrochloride
  • 0.6 grams of of crystalline sodium acetate
  • 50 mL pyrex test tube or a suitable test tube perferably pyrex or borosil.
  • 400 mL beaker to prepare a water bath
  • A water heater electric or bunsen burner
  • Wire gauze if using the bunsen burner
  • A tripod stand if using the bunsen burner.

Procedure

In order to prepare the compound, first you need to set up the water bath using a 400 mL beaker that is filled with about 300 mL water.
Now dissolve 0.4 grams of phenyl hydrazine and 0.6 grams of crystalline sodium acetate in 4 or 5 mL of distilled water.
Add this mixture to 0.5 grams of sugar dissolved in 3 or 4 mL of distilled water. Loosely close the test tube with a stopper to hold the reagents. Now place the test tube in the hot water bath, with gentle stirring or agitation. The time taken for the osazone to appear is a sure sign of the type of sugar used. Once the precipitation of the osazone is complete, filter the precipitate and recrystallize the osazone from 50% alcohol

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Benzoic Acid From Benzyl Chloride

Preparation of Benzoic Acid From Benzyl Chloride

Preparation of Benzoic Acid from Benzoyl chloride

In this reaction a side chain oxidation is performed. In order to achieve this benzyl chloride is mixed with sodium carbonate solution and is oxidized with potassium permanganate solution. The sodium salt of benzoic acid is formed, this is acidified with concentrated hydrochloric acid when benzoic acid crystallizes out. Preparation benzoic acid benzyl chloride

Benzoic acid benzyl chloride
Preparation of Benzoic acid from Benzyl Chloride

 

 

 

 

 

Reagents
  • Benzyl chloride 2 ml
  • Anhydrous sodium carbonate 2 g in 20 ml of water
  • Potassium permanganate 8 g in 80 ml water
Procedure:

About 2 ml of benzyl chloride is added to a solution of about 2 g rams of anhydrous sodium carbonate dissolved in 20 ml of distilled water. The mixture is taken in a round bottom flask. The round bottom flask is fitted with a water refulx condenser and heated . 4 gams of potassium permanganate in 80 ml of water is added in small quantities through the water condenser until a permanent pink color persists even after continuous boiling. It is boiled for about 1 hour. The mixture is not transferred to a beaker. About 4 grams of sodium sulfite are added to this mixture. Now add concentrated hydrochloric acid to this solution until the solution is acidic. The solution is cooled, precipitated benzoic acid is filtered and washed. The acid is recrystallized from boiling water.
The yield of benzoic acid is about 2 grams and the melting point is 1210C
Care should be taken while setting up the equipment’s, the hydrochloric acid used in converting the sodium salt of benzoic acid is concentrated, so extreme care should be taken while handling the chemicals and using them. Wear goggles , gloves and apron while performing the experiment. Use common sense while performing any lab activity and read your lab manual before doing any experiment.

 

 

Iodoform Preparation

Iodoform Preparation

Iodoform Preparation in the lab for confirmation of presence of a ketone. Confirmation of the presence of a Ketone by the preparation of iodoform. The presence of a ketone can be confirmed by the preparation a yellow colored solid called iodoform. Secondary alcohols can be chemically reduced to a ketone using a reducing agent. The ketone that is produced can be converted to iodoform. Below is the procedure for the preparation of iodoform from acetone. Nail polish remover is acetone. The IUPAC name for acetone is called propanone.

Method of preparation

Acetone when mixed with potassium carbonate and solid iodine can produce iodoform

Materials required

  • Iodine crystals 5 grams
  • Solid potassium carbonate 5 grams
  • Propanone or Acetone 3.5 mL

Reaction

CH3COCH3 + 3I2 → CI3COCH3 + 3HI
CI3COCH3 + NaOH → CHI3 + CH3COONa

Procedure

Mass 5 grams of potassium carbonate K2CO3 . Dissolve in 20 mL of distilled water, taken in an Erlenmeyer flask. Stir the mixture constantly to ensure the potassium carbonate is completely dissolved. The mixture is then placed in a warm water bath, which is at about 75 to 80 degrees Celsius. Cool the solution when the reaction is complete.  The yellow crystals formed is iodoform. Separate the iodoform from the mixture by filtration. Wash the iodoform with water. A small sample of the iodoform is recrystallized from alcohol. Dry the iodoform crystals.

Theoretical Yield of iodoform is 1.15 grams
The melting point of iodoform is 119 oC

Copyrights © Stan Vincent for the procedure. All rights reserved.

Iodoform Preparation in the lab for confirmation of presence of a ketone
Triiodomethane

http://commons.wikimedia.org/wiki/File:Triiodomethane_%28iodoform%29.jpg

Preparation of Phenyl benzoate

Preparation of Phenyl benzoate

Phenyl benzoate
phenyl benzoate

Preparation Method

Phenol is treated with benzoyl chloride in presence of sodium hydroxide for preparation  phenyl benzoate.

Reagents

  • Phenol 1 g
  • Sodium hydroxide 1.5 g
  • Benzoyl chloride 2 mL

Procedure

For the preparation  phenyl bensoate, about 1 gram of phenol is dissolved in 15 mL of 10% sodium hydroxide solution in an Erlenmeyer flask. 2 mL of benzoyl chloride is added. Close the mouth of the flask with a rubber stopper and shake vigorously for about 30 minutes. When the reaction is complete, the smell of benzoyl chloride will disappear. The precipitated phenyl benzoate is separated by filtration, washed with water, dried and the yield is noted. A small quantity is recrystallized from alcohol. Determine the melting point of the product.

  • Theoretical yield is approximately 2 grams
  • The melting point of phenyl benzoate is 162 0C

Links to other preparations

 

 

Acknowledgement for images used

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Preparation of acetanilide from aniline

Preparation of acetanilide from aniline

Preparation  of Acetanilide C6H5NHCOCH3 from aniline. Preparation acetanilide aniline.

Acetanilide Image in public domain
Acetanilide Molecule

 

 

 

 

Preparation method:

Preparation of acetanilide from aniline. Aniline is refluxed with glacial acetic acid in the presence of fused sodium acetate when acetanilide is obtained. This is the method used in the preparation  of acetanilide from aniline.

Write reaction here

Chemicals Required

1. Freshly distilled aniline 5 mL
2. Glacial acetic acid 6 mL
3. Freshly fused sodium acetate 2 g

Procedure

About 5 ml of aniline, 6 ml  glacial acetic acid and 2 grams fused sodium acetate are taken in a round bottom flask. Make sure the mouth of the flask,  is fitted with a long air condenser and the mixture is gently re-fluxed,  by heating the contents of the round bottom flask on a wire gauze.  Continue the heating for 2 to 3 hours.

The mixture is poured while hot into 100 mL of cold water. contained in a beaker with constant  stirring. Filter the cooled mixture using a Buschner funnel. The slightly colored substance is dissolved in about 150 mL of boiling water, heated with 1 gram of animal charcoal (or activated charcoal) and filtered through a hot water funnel. Allow the filterate to cool.  Now the precipitated acetanilide is filtered, washed with a small quantity of water and dried. The yield and the melting point determined.

Theoretical yield: of acetanilide is about 5.5 gram
Melting point: of acetanilide is 114 degrees Celsius

Acetanilide Crystals

Acetanilide
Acetanilide Crystals

 

 

 

 

 

 

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