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Topic: What is the amide link  (Read 29302 times)

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Offline jsmith613

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What is the amide link
« on: August 18, 2009, 02:51:21 PM »
i know that nylon is
HOOC--O--CONH--O--NH2 (O = 4 / 6 carbon atoms)
and i know CONH is the amide molecule but what is the amide link

Offline Borek

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Re: What is the amide link
« Reply #1 on: August 18, 2009, 03:32:14 PM »
http://en.wikipedia.org/wiki/Amide

CONH is not a molecule.
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Offline jsmith613

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Re: What is the amide link
« Reply #2 on: August 18, 2009, 03:51:28 PM »
http://en.wikipedia.org/wiki/Amide

CONH is not a molecule.

if CONH is not a molecule then is the CONH the amide link within nylon. (is CONH always the amide link)

Offline cliverlong

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Re: What is the amide link
« Reply #3 on: August 18, 2009, 05:06:10 PM »

if CONH is not a molecule then is the CONH the amide link within nylon. (is CONH always the amide link)
Yes, CONH is the amide which forms the "bridge" in nylon and other polyamides.

Can you draw the structure of CONH to explain why it can act as a "bridging link" in (very) long chain (or branched) molecules?

Which two organic groups can (there are more than two actually) form the amide group?

Can you list two sets of simple monomers that include the groups to make amide bonds? (more simply, can you explain the similarity and differences in the bonding in polyamides versus polypeptides/proteins ?)

Clive

Offline jsmith613

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Re: What is the amide link
« Reply #4 on: August 18, 2009, 05:24:14 PM »

if CONH is not a molecule then is the CONH the amide link within nylon. (is CONH always the amide link)
Yes, CONH is the amide which forms the "bridge" in nylon and other polyamides.

Can you draw the structure of CONH to explain why it can act as a "bridging link" in (very) long chain (or branched) molecules?

Which two organic groups can (there are more than two actually) form the amide group?

Can you list two sets of simple monomers that include the groups to make amide bonds? (more simply, can you explain the similarity and differences in the bonding in polyamides versus polypeptides/proteins ?)




Clive

a) structure of CONH, it is the bridging link as the CO from the carboxyl acid and the NH from diamine join together CO-NH
H
C=O
   N 
b) the groups are carboxylic acid + diamine
c) pentamethylene diamine + sebacic acid form Nylon 5,10

IS THIS CORRECT?
« Last Edit: August 18, 2009, 05:52:41 PM by jsmith613 »

Offline cliverlong

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Re: What is the amide link
« Reply #5 on: August 19, 2009, 02:35:58 AM »
Yes, CONH is the amide which forms the "bridge" in nylon and other polyamides.

Can you draw the structure of CONH to explain why it can act as a "bridging link" in (very) long chain (or branched) molecules?

Which two organic groups can (there are more than two actually) form the amide group?

Can you list two sets of simple monomers that include the groups to make amide bonds? (more simply, can you explain the similarity and differences in the bonding in polyamides versus polypeptides/proteins ?)




Clive

a) structure of CONH, it is the bridging link as the CO from the carboxyl acid and the NH from diamine join together CO-NH
H
C=O
   N 
b) the groups are carboxylic acid + diamine
c) pentamethylene diamine + sebacic acid form Nylon 5,10

IS THIS CORRECT?
Almost spot on.

I would write

The amide bond is formed by the elimination of a water molecule (condensation) between the organic groups: COOH (carboxylic acid) and NH2 (amine, not diamine)

Another pair of organic groups that will form an amide bond are: COCl (acyl chloride) and NH2 (amine) by elimination of HCl.

Now, the above forms one amide link. There has to be something specific about the two monomers that react together to form a long chain. Can you find the structural formulae for the monomers pentamethylene diamine and sebacic acid? What is it about these two monomers that allow long chains to be formed rather than just one amide link?

Look for the structure of two amino acids, say lycine and alanine (any two will do). How do they bond to form a polypeptide such as ...lycine-alanine-lycine-alanine-lycine-alanine.... ?

What is the similarity and difference in the bonding between the monomers in nylon (polyamide) versus a polypeptide?

Clive

Offline cliverlong

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Re: What is the amide link
« Reply #6 on: August 19, 2009, 02:43:03 AM »
I think the two monomers that make up nylon 6,6

http://en.wikipedia.org/wiki/Hexamethylene_diamine

http://en.wikipedia.org/wiki/Adipic_acid

(Look at the structural formulae)

make it easier to see what chemical feature the monomers need in order for chains to form.

Clive

Offline jsmith613

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Re: What is the amide link
« Reply #7 on: August 19, 2009, 06:20:43 AM »
I think the two monomers that make up nylon 6,6

http://en.wikipedia.org/wiki/Hexamethylene_diamine

http://en.wikipedia.org/wiki/Adipic_acid

(Look at the structural formulae)

make it easier to see what chemical feature the monomers need in order for chains to form.


what is the feature???

Offline jsmith613

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Re: What is the amide link
« Reply #8 on: August 19, 2009, 06:31:21 AM »

Quote

a) Can you find the structural formulae for the monomers pentamethylene diamine and sebacic acid? What is it about these two monomers that allow long chains to be formed rather than just one amide link?

Look for the structure of two amino acids, say lycine and alanine (any two will do). How do they bond to form a polypeptide such as ...lycine-alanine-lycine-alanine-lycine-alanine.... ?

b) What is the similarity and difference in the bonding between the monomers in nylon (polyamide) versus a polypeptide?

Clive

for a) are you looking for the fact that both monomers after loosing an H+ and OH- become charged and hence want to join together with another molecule. The ends of one join on to the beginning of the next molecule
for b) i am not quite sure of the differences, please can you tell me some

Offline cliverlong

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Re: What is the amide link
« Reply #9 on: August 19, 2009, 01:28:35 PM »
I think the two monomers that make up nylon 6,6

http://en.wikipedia.org/wiki/Hexamethylene_diamine

http://en.wikipedia.org/wiki/Adipic_acid

(Look at the structural formulae)

make it easier to see what chemical feature the monomers need in order for chains to form.


what is the feature???
Which reactive chemical groups are at the end of Hexamethylene diamine and Adipic acid? Look at the chemical structural formulae in the wikipedia links I sent you (top right hand corner of article).

How do these groups react to form amide bonds.

What is "special" about the position and number of functional groups on each monomer that mean chains can be formed?

Clive

Offline cliverlong

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Re: What is the amide link
« Reply #10 on: August 19, 2009, 01:30:47 PM »
<< snip >>
. hence want to join together with another molecule. The ends of one join on to the beginning of the next molecule  ..
<< snip >>
That's the basis of the idea. The question is why does that work for the particular monomers I listed?

Offline jsmith613

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Re: What is the amide link
« Reply #11 on: August 19, 2009, 03:30:43 PM »


Quote
Which reactive chemical groups are at the end of Hexamethylene diamine and Adipic acid? Look at the chemical structural formulae in the wikipedia links I sent you (top right hand corner of article).

How do these groups react to form amide bonds.

What is "special" about the position and number of functional groups on each monomer that mean chains can be formed?

Clive

is it that the ends of the monomers contain the SAME atoms (OH-OH) and (H2N-NH2).
I still dont know what is special about the position and number of functional groups, please enlighten me.

Offline jsmith613

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Re: What is the amide link
« Reply #12 on: August 19, 2009, 03:31:33 PM »


Quote
Which reactive chemical groups are at the end of Hexamethylene diamine and Adipic acid? Look at the chemical structural formulae in the wikipedia links I sent you (top right hand corner of article).

How do these groups react to form amide bonds.

What is "special" about the position and number of functional groups on each monomer that mean chains can be formed?

Clive

is it that the ends of the monomers contain the SAME atoms (OH-OH) and (H2N-NH2).
I still dont know what is special about the position and number of functional groups, please enlighten me.

Offline jsmith613

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Re: What is the amide link
« Reply #13 on: August 19, 2009, 03:33:03 PM »

Quote
Which reactive chemical groups are at the end of Hexamethylene diamine and Adipic acid? Look at the chemical structural formulae in the wikipedia links I sent you (top right hand corner of article).

How do these groups react to form amide bonds.

What is "special" about the position and number of functional groups on each monomer that mean chains can be formed?

Clive

is it that the ends of the monomers contain the SAME atoms (OH-OH) and (H2N-NH2).
I still dont know what is special about the number of functional groups, please enlighten me. But with the position, they are ends are a reflection of the other (basically the opposite way round with the same atoms)

Offline jsmith613

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Re: What is the amide link
« Reply #14 on: August 19, 2009, 03:33:33 PM »
Quote
Which reactive chemical groups are at the end of Hexamethylene diamine and Adipic acid? Look at the chemical structural formulae in the wikipedia links I sent you (top right hand corner of article).

How do these groups react to form amide bonds.

What is "special" about the position and number of functional groups on each monomer that mean chains can be formed?

Clive

is it that the ends of the monomers contain the SAME atoms (OH-OH) and (H2N-NH2).
I still dont know what is special about the number of functional groups, please enlighten me. But with the position, they are ends are a reflection of the other (basically the opposite way round with the same atoms)


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