goldberg
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Quantitative analysis of ketones
I'm looking for a way to determine concentration of ketone in aqueous solution(or water+ cosolvent system if given ketone is not water soluble).
I tried to search on the Web for information about tiration of ketones but i have only found Karl-Fisher method of determination of water in ketones.
With aldehydes i could to permanganometry to oxidize ketone to correspodning carboxylic acid.
I'm interested in general method but i'm especially interested in benzylic ketones(for example acetophenone and propiophenone).
Is it possible to titrate ketone? I do not have access to chromatography, which would solve this problem.
How about cyclic amperometry? In theory it is possible to electrochemically reduce ketone and measure current.
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macckone
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The usual method would be to form an abduct with the ketone.
Sodium bisulfite will generally form an insoluble abduct.
MEK and Acetone are more soluble.
https://erowid.org/archive/rhodium/chemistry/eleusis/bisulfi...
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Bonee
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Sodium nitroprusside combined with a strong base gives a red coloured product if applied to methyl ketones.
https://en.wikipedia.org/wiki/Sodium_nitroprusside
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Dr.Bob
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Most ketones react with hydrazines to form imines/hydrazides, the typical one is dintrophenylhydrazine, which is a common test for ketones. Try
googling "Quantitative analysis of ketones hydrazide" and you will find several refs.
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goldberg
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@Dr.Bob Unfortunately i did not much about this method.
From i have read sodium nitroprusside can be used to detect ketones, but how about quantitative analysis?
Moreover this reaction is specyfic to methyl ketones and i need a general method.
How about electrochemical methods?
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DraconicAcid
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For quantitative methods, I can think of two. Gravimetric methods (make a semicarbazide or DNP derivative, and then weigh it), or colorimetry (make
the nitroprusside derivative, and find its concentration by measuring its absorbance).
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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AvBaeyer
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Goldberg:
You should seek out the following book for help with your problem:
S. Sigia, "Quantitative Organic Analysis via Functional Groups," Wiley, New York, 1954, see p. 21
(Just checked ABEbooks site. Several editions of this book are available quite cheaply. Bought one myself.)
I have seen this work referenced regarding quantitative analysis of carbonyl compounds though I have not seen the book myself. The following book,
which I own, has a good discussion of the problems associated with carbonyl group analysis:
J.S. Fritz and G.S. Hammond, "Quantitative Organic Analysis," John Wiley and Sons, New York, 1957, see preface and Chapter 2.
AvB
[Edited on 25-8-2020 by AvBaeyer]
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macckone
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Quantitative Organic Analysis - Fritz and Hammond - Full view but not easily downloadable
https://babel.hathitrust.org/cgi/pt?id=mdp.39015003705269
Quantitative Organic Analysis via Functional Groups Sigia
https://archive.org/details/unset0000unse_e3d7
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goldberg
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Thanks a lot. I'm reading Quantitative organic analysis via functional and this book gave me an answer.
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