Chemguide: Support for CIE A level Chemistry

35.1: Condensation polymerisation

Learning outcome 35.1.2

This is about the formation of polyamides and polypeptides. A peptide link is exactly the same as an amide link. Chemists call them amides; biologists and biochemists call them peptides. In both cases, you are forming polymers containing the link -CONH-.

Statement 35.1.2(a)

This is about the formation of polyamides from the reaction between a diamine and a dicarboxylic acid or dioyl chloride.

You will find rather more than you need on the page about polyamides.

The only thing that you definitely don't need to worry about on this page is the manufacture of nylon-6,6. The preparation of nylon-6,6 in the lab via the nylon rope trick is just a matter of interest as well. However, although you won't be asked about the experimental details of this, you could be given the structure of two monomers similar to these and asked for the structure of the polymer as a part of statement 35.1.3.

The hydrolysis of polyamides comes up in a later statement in this section.

The uses of the polymers at the bottom of the page is just a matter of interest.

Statement 35.1.2(b)

Despite the comment on the Chemguide page, this statement does want you to know about the formation of polyamides from an aminocarboxylic acid, and so you will need to know about nylon-6.

Teacher support material simplifies the starting material for nylon-6, by starting from a chain molecule rather than the cyclic caprolactam. They suggest starting from 6-aminohexanoic acid. Make sure that you can see how the nylon-6 structure is derived from this.

6-aminohexanoic acid: H₂NCH₂CH₂CH₂CH₂CH₂COOH

Check the structure you come up with against the one under Nylon-6 on the page you have read.

If you can't do this, then you haven't understood this page. Go back and look again at how water gets eliminated during the formation of nylon-6,6.

Statement 35.1.2(c)

This statement is about the formation of polyamides (polypeptides) from amino acids.

Look at the beginning of the page on protein structure. Read down as far as - but not including - the primary structure of proteins.

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