1. Amides David Matin City and Islington College

2. Learning Outcomes 8th functional group – amides Drawing amides
Naming amides
Physical properties of amides
Chemical properties of amides
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3. Amides
Amides are derivatives of carboxylic acids in which a nitrogen group (–NH2) replaces the –OH group of carboxylic acids.
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4. Preparation of Amides
Amides are produced by reacting a carboxylic acid with ammonia or a 1 or 2 amine with heat.
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5. Naming Amides
For IUPAC naming, the -oic acid from the carboxylic acid name ending is replaced with -amide
For common names, the -ic acid from the carboxylic acid name ending is replaced with -amide O
 methanamide (IUPAC)
H—C—NH2 formamide (common)
 propanamide (IUPAC)
CH3—CH2—C—NH2 propionamide (common)
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6. Naming Amides with N Groups
An alkyl group attached to the nitrogen of an amide is named with the prefix N-, followed by the alkyl name. O H  │ CH3 —C—N—CH3 N-methylethanamide (IUPAC) N-methylacetamide (common) O H  │ CH3—CH2 —C—N—CH2—CH3 N-ethylpropanamide (IUPAC) N-ethylpropionamide (common)
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7. Aromatic Amide The aromatic amine is benzamide.
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8. Learning Check Give the IUPAC and common names for the following.
butanamide (IUPAC)
butryamide (common)
N-ethylethanamide (IUPAC)
N-ethylacetamide (common)
Hand-out and Group discussion asking for the answer to the question (also a slideshow slide)

9. Learning Check Draw the structures of the following. Pentanamide
N-methylbutyramide
Hand-out and Group discussion asking for the answer to the question (also a slideshow slide)

10. Some Amides in Health and Medicine
Urea is the end product of protein metabolism.
Saccharin is an artificial sweetener.
Some amides, such as phenobarbital (Luminal) and pentobarbital (Nembutal), are barbiturates.
Acetaminophen is used to reduce fever and pain.
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11. Some Amides in Health and Medicine
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12. Solubility of Amides
Amides with one to five carbon atoms are soluble in water
because they can form hydrogen bonds with water molecules.
Hydrogen bonding effects are diminished when molecules have
more than five carbon atoms, therefore reducing solubility.
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13. Hydrolysis of Amides Amides undergo
acid hydrolysis to produce a carboxylic acid and an ammonium salt
base hydrolysis to produce the salt of a carboxylic acid and an amine or ammonia
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14. Hydrolysis Reactions
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15. Preparation of amides from carboxylic acids, acyl chlorides (acid chlorides) and acid anhydrides
Making amides from carboxylic acids
ammonium ethanoate is made by adding ammonium carbonate to an excess of ethanoic acid.
When the reaction is complete, the mixture is heated and the ammonium salt dehydrates producing ethanamide.
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Summary of the process
The carboxylic acid is first converted into an ammonium salt which then produces an amide on heating.
The ammonium salt is formed by adding solid ammonium carbonate to an excess of the acid.

16. Preparation of amides from carboxylic acids, acyl chlorides (acid chlorides) and acid anhydrides
Making amides from acyl chlorides
the ammonia reacts with the ethanoyl chloride to give ethanamide and hydrogen chloride gas.
Then the hydrogen chloride produced reacts with excess ammonia to give ammonium chloride.
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. . . and you can combine all this together to give one overall equation:

17. Preparation of amides from carboxylic acids, acyl chlorides (acid chlorides) and acid anhydrides
Making amides from acid anhydrides
An acid anhydride is what you get if you remove a molecule of water from two carboxylic
acid -COOH groups.
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18. the two products of the reaction overall can look confusingly similar
Continue….
ethanamide is formed together with ethanoic acid
Then the ethanoic acid produced reacts with excess ammonia to give ammonium ethanoate
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. . . and you can combine all this together to give one overall equation
the two products of the reaction overall can look confusingly similar

19. Polyamides
Polyamides are polymers where the repeating units are held together by amide links.
An amide group has the formula - CONH2. An amide link has this structure:
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20. Nylon
In nylon, the repeating units contain chains of carbon atoms. There are various different types of nylon depending on the nature of those chains.
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21. Continue….
Nylon-6,6 Nylon-6,6 is made from two monomers each of which contain 6 carbon atoms - hence its name.
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22. Continue….
1. One of the monomers is a 6 carbon acid with a -COOH group at each end - hexanedioic acid.
2.The other monomer is a 6 carbon chain with an amino group, -NH2, at each end. This is 1,6-diaminohexane (also known as hexane-1,6-diamine).
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23. Continue….
When these two compounds polymerise, the amine and acid groups combine, each time with the loss of a molecule of water. This is known as condensation polymerisation.
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24. Continue…
Nylon-6 Nylon-6 is made from a monomer called caprolactam Notice that this already contains an amide link. When this molecule polymerises, the ring opens, and the molecules join up in a continuous chain.
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25. Kevlar
Kevlar is similar in structure to nylon-6,6 except that instead of the amide links joining chains of carbon atoms together, they join benzene rings.
The two monomers are benzene-1,4-dicarboxylic acid and 1,4-diaminobenzene.
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If you line these up and remove water between the -COOH and -NH2 groups in the same way as we did with nylon-6,6, you get the structure of Kevlar:

26. Uses of Polyamides
Nylon Apart from obvious uses in textiles for clothing and carpets, a lot of nylon is used to make tyre cords - the inner structure of a vehicle tyre underneath the rubber. The fibres are also used in ropes, and nylon can be cast into solid shapes for cogs and bearings in machines, for example. Kevlar Kevlar is a very strong material - about five times as strong as steel, weight for weight. It is used in bulletproof vests, in composites for boat construction, in lightweight mountaineering ropes, and for lightweight skis and racquets - amongst many other things.
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27. Hydrolysis of Polyamides
Simple amides are easily hydrolysed by reaction with dilute acids or alkalis.
Polyamides are fairly readily attacked by strong acids, but are much more resistant to alkaline hydrolysis. Hydrolysis is faster at higher temperatures. Hydrolysis by water alone is so slow as to be completely unimportant. Kevlar is rather more resistant to hydrolysis than nylon is.
If you spill something like dilute sulphuric acid on a fabric made from nylon, the amide linkages are broken. The long chains break and you can eventually end up with the original monomers - hexanedioic acid and 1,6-diaminohexane.
Because you produce small molecules rather than the original polymer, the fibres are destroyed, and you end up with a hole!
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28. For further information please contact The STEM Alliance or visit
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