draculic acid69
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Need advice on ester formation
Let's say I want to make an ester from benzoic acid and ethylene glycol but want to leave one hydroxyl group free to halogenate to a bromide.other
than using 1-1 moles of each reactant what do I need to do/not do to ensure the max yeild of desired ester and avoid the diester?
And what order should this be done in:ester formation then halogenation or halogenation then esterification? Any advice would be appreciated.
[Edited on 14-2-2019 by draculic acid69]
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Sigmatropic
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Fischer esterferication of 2-bromoethanol and benzoic acid comes to mind. This method is used alot in carbohydrate country to give bromoethyl
glycosides. But uses excess bromoethanol.
I doubt there is a high yielding procedure to bromoethanol from ethylene glycol. But if there is that would be the way to go.
The other approach is make 2-hydroxyethyl benzoate under somewhat different conditions... Say, benzoic anhydride(or chloride) in a large excess
ethylene glycol.
Or alkylation of benzoic acid with excess ethylene bromide.
The possibilities are numerous, have you tried a literature search using scifinder/reaxys/ect?
[Edited on 14-2-2019 by Sigmatropic]
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Dr.Bob
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Going to be tough, if you use 10 eq of the diol, it might work, but then you have to clean that up. You could try to esterify the acid with
2-chloroethanol, then react the halogen, but not sure how clean that will be. I have done reactions like that, but they are rarely clean, they work
best is you can distill the product away or easily purify it. Might be easier to make the diester and then cleave half of it off with a specific
amount of a base, that might give a mixture, but be easier to separate.
Better way is to use a molecule with two groups, such as methyl glycolate, react the hydroxy to the ester, then reduce the ester to an alcohol to
convert to the bromide. More steps, but only one major product at each step. Or post the entire route, and their might be a simpler way.
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Sigmatropic
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10 minutes of searching later: http://www.orgsyn.org/demo.aspx?prep=CV4P0084
Be sure to check out ref 8 and 11
Unfortunately, I don't have access to verify, But this would be the correct author, year and journal.
https://onlinelibrary.wiley.com/doi/abs/10.1002/jlac.1860113...
Still good luck trying to replicate 1860 chemistry, but should be easily within reach of the nowadays amateur chemist.
[Edited on 14-2-2019 by Sigmatropic]
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draculic acid69
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Halogenation then esterification seems to be the way to go
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