Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: tonja79 on March 02, 2015, 06:09:49 PM
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Hi all,
I'm new in this forum and I searched something about this topic but I cannot find nothing.
The question that I want to submit you is: What is the acidic pH where I can have vitamin c opening ring?
Thanks
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It is a forum policy that you must show an attempt before others can help you. Do you have any references to this reaction?
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What is the acidic pH where I can have vitamin c opening ring?
I don't think you will find an answer to THIS question. I think if you add ethyl acetate to water, it will very slowly hydrolyze. The entropy will increase therefore the thermodynamic equilibrium favors hydrolysis. However, it will be so slow that a titration would never reveal a pKa of acetic acid, the hydrolysis product.
The pKa of ethyl acetate/acetic acid could be determined by treating it with an excess of base (to increase the hydrolysis rate) and back titrate this solution to determine the pKa of the acetic acid.
The above is what I think is correct. If so, then I think the question being asked is about the two pKa values of ascorbic acid, but the structure of which is a lactone. What I expect is that as more base is added, the faster the hydrolysis will occur. The hydrolysis products will consume the base and slow the hydrolysis. These will alter the rate, but not the equilibrium.