Poly(ethanol) is produced in an ester exchange reaction between poly(ethenyl ethanoate) and methanol
How can this work, though? I thought that in an ester exchange reaction an alcohol group swaps with another alcohol group. Here the alcohol and carboxyllic acid group are swapping??
The alcohol groups are swapping with each other. The original alcohol group is the polymer chain, and that is getting replaced with methanol, to leave the alcoholic polymer.
The alcohol groups are swapping with each other. The original alcohol group is the polymer chain, and that is getting replaced with methanol, to leave the alcoholic polymer.
no it is not in my book i looked for another explanation online but could not find it
An ester is analagous to an acyl chloride with an OR group instead of a Cl, and they are less reactive. What would the reaction between methanol and an acyl chloride be?
An ester is analagous to an acyl chloride with an OR group instead of a Cl, and they are less reactive. What would the reaction between methanol and an acyl chloride be?
well I would eliminate the Cl from the acyl and the H from methanol so the link would be ...C-O-C..
well I would eliminate the Cl from the acyl and the H from methanol so the link would be ...C-O-C..
So, draw out your polymer. The O-Polymer bit is your OR of the ester, attack the C=O with your methanol, push the arrows in exactly the same way and you should get the product.
So, draw out your polymer. The O-Polymer bit is your OR of the ester, attack the C=O with your methanol, push the arrows in exactly the same way and you should get the product.
so ester exchange and transesterfication are different then, right?
So, draw out your polymer. The O-Polymer bit is your OR of the ester, attack the C=O with your methanol, push the arrows in exactly the same way and you should get the product.
I have now included arrows and it seems wrong, sorry
this is hand drawn by me is this correct (It looks like it is but just wanna double check
Yes although strictly in the step where you lose the H+ it would be removed by a solvent (probably water molecule), rather than just falling off.
The mechanism is probably a bit beyond your course, and in reality alcohols are not very good nucleophiles so you would use either an acid catalyst which protonates the C=O of the ester and makes it more reactive (like an acid chloride), or a base which deprotonates the alcohol and makes that more reactive (better nucleophile).
Still, the best way to understand the reaction is to understand the mechanism
I'm not quite sure what reaction you're trying to do! An ester will not react with a simple carboxylic acid.
oh ok, my revision guide says it will but no mechanism made sense.... anhydries, I presume they just split at the O=C-C=O
e.g: (CH3CO)2O
Having never studied them before in depth I don't know if the two groups have to be the same if not then how do I know which "part" takes the H bit of the alcohol and which bit takes the O-R bit from the alcohol
oh ok, my revision guide says it will but no mechanism made sense.... anhydries, I presume they just split at the O=C-C=O
e.g: (CH3CO)2O
Having never studied them before in depth I don't know if the two groups have to be the same if not then how do I know which "part" takes the H bit of the alcohol and which bit takes the O-R bit from the alcohol
What sort of product did the revision guide arrive at?