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Friday, August 16, 2013

Preparation of Acetamide - Amidation of Ester - Lu Le Laboratory



Acetamide is an organic compound. It is the simplest amide derived from acetic acid. It finds some use as a plasticizer and as an industrial solvent. The related compound N,N-dimethylacetamide (DMA) is more widely used, but it is not prepared from acetamide.

Acetamide has been detected near the center of the Milky Way galaxy. This finding is potentially significant because acetamide has an amide bond, similar to the essential bond between amino acids in proteins. This finding lends support to the theory that organic molecules that can lead to life (as we know it on Earth) can form in space.

In addition, acetamide is found infrequently on burning coal dumps, as a mineral of the same name.  (Wikipedia)

Reaction Equations


Mechanism


Chemicals

1.     Ethyl acetate: 30.00 g
2.     Aqueous ammonia: 40.00 g

 
Procedure

1.     Add 33.26 mL ethyl acetate and 44.44 mL aqueous ammonia in a 150 mL round-bottomed bottle.
 

2.     Stir it thoroughly at 25~27℃ for 2~3 hr.
 


 

 
3.     Stand the mixture for 24 hr. If the solution would not separate into two layers, it shows the reaction is finished.
4.     Distill the mixture to concentrate the mixture to the half of the original volume.
 

Some ammonia will release in this process, remember to absorb the exhaust.

5.     Filter the solution.
6.     Concentrate the solution to viscosity.
 

 
7.     Cool the solution in an ice bath.
 


 
8.     Filter the solution and wash it with a little amount of cold ethanol.

 
9.     Put it in an oven to evaporate ethanol. 

 
10.   Put it in a vacuum desiccator for 24 hr.


 
11.   Calculate the yield.

Experimental Record

Weight of Ethyl acetate
30.0000 g
Weight of acetamide
8.1719 g
Theoretical Weight of Acetamide
20.1124 g
Yield
(8.1719 g) / (20.1124 g) x 100%

= 40.63 %

 

2 comments:

  1. cool. But can you say,what are the by-side products? Why does the yield is so poor?

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  2. The products are acetamide, water, ethanol, and and ammonia will also be released from solution. The hydrolysis of acetamide is also possible, so the products of that reaction are also possible, of which, ammonia becomes a product.

    ReplyDelete