ps1265A
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So when an alcohol and a carboxylic acid react together, we form an ester and water is produced.
In order for this to happen, OH from the carboxylic acid and H from the alcohol are removed.

But why isn't this the case in triglycerides. Glycerol contributes the OH and the fatty acid (i.e the carboxylic acid) only contributes a H. Why is this? Or shall I just accept it?


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Treen98
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(Original post by ps1265A)
So when an alcohol and a carboxylic acid react together, we form an ester and water is produced.
In order for this to happen, OH from the carboxylic acid and H from the alcohol are removed.

But why isn't this the case in triglycerides. Glycerol contributes the OH and the fatty acid (i.e the carboxylic acid) only contributes a H. Why is this? Or shall I just accept it?


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I'm not entirely sure of what you're asking but remember that glycerol has three -OH groups, not just one
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Feraligatr
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(Original post by ps1265A)
So when an alcohol and a carboxylic acid react together, we form an ester and water is produced.
In order for this to happen, OH from the carboxylic acid and H from the alcohol are removed.

But why isn't this the case in triglycerides. Glycerol contributes the OH and the fatty acid (i.e the carboxylic acid) only contributes a H. Why is this? Or shall I just accept it?


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Glycerol has the functional group -OH and is an organic compound correct?

Therefore Glycerol is a type of alcohol

Now, in regards to your question, it doesn't really matter what contributes what in this scenario since either way an ester bond forms

H contributed from Glycerol and OH contributed from the fatty acid will be the same as saying that OH is contributed from the glycerol molecule and the H is contributed from the fatty acid

Either way, you form the same bond (i.e. an ester bond) and the same product (i.e an ester - in this case, the ester is a triglyceride)
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Hayley Williams
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(Original post by ps1265A)
So when an alcohol and a carboxylic acid react together, we form an ester and water is produced.
In order for this to happen, OH from the carboxylic acid and H from the alcohol are removed.

But why isn't this the case in triglycerides. Glycerol contributes the OH and the fatty acid (i.e the carboxylic acid) only contributes a H. Why is this? Or shall I just accept it?


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Accept it x


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kanra
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(Original post by ps1265A)
So when an alcohol and a carboxylic acid react together, we form an ester and water is produced.
In order for this to happen, OH from the carboxylic acid and H from the alcohol are removed.

But why isn't this the case in triglycerides. Glycerol contributes the OH and the fatty acid (i.e the carboxylic acid) only contributes a H. Why is this? Or shall I just accept it?


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Have you done anything on acid strength/delocalisation of negative charges and the actual mechanism of ester bond formation?

In order to form the bond, you need to deprotonate (remove H+) from an OH group. This would leave O-, which then attacks an electropositive carbon atom. O- is unstable on glycerol, because the negative charge only exists on one oxygen. In carboxylic acids, the two oxygens attached to the terminal carbon are essentially the same once you remove the proton, so the negative charge can be "shared" between two oxygens.

TL;DR - there is a reason why it's like that, but unless you've covered certain aspects of the course, what I've typed won't make much sense (in which case just accept it).
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Pigster
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(Original post by kanra)
In order to form the bond, you need to deprotonate (remove H+) from an OH group.
But, the first step of an esterification mechanism is to protonate the carboxylic acid, not to de-protonate it.
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