romanceliu
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Difluoroacetic acid
now i made the product the Difluoroacetic acid i have some question to ask ,
first . the difluoriacetic is volatilization easy , but i do not find the good means to conrol the volatilization .
so the yield is very low ,
second , the water of difluoriacetic is high , how remove ?
i can get the difluoriacetic from the difluriactic salt.
can u gei me synthis route economy another ?
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kclo4
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So, you have a Diflouroacetate?
I'd imagine adding a conc. acid would produce it then. Sulfuric perhaps?
and then distillation.
What is Difluoroacetic acids boiling point?
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romanceliu
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difluoroacetic'bolling point is about 130 degree .the means the hydrolysate of Diflouroacetate is not economy , but if add the sulfuric , the
hydrolysate produce a lot of water , it is difficulity to remove , when distillation.
now i synthes it from amide and alcohols .then acific , i will get the product what i want to .but the reaction do not react complete. i want to
find the proper catalyst to improve the reaction in esterification .
can u gei me some advice ?
thanks
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kclo4
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How much are you producing?
Explain your goals in what you are doing etc.
What is it you are starting from exactly to make this?
You are very hard to understand.
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vulture
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| Quote: |
but if add the sulfuric , the hydrolysate produce a lot of water , it is difficulity to remove , when distillation. |
Hydrolyse, then add excess concentrated sulfuric acid. This will retain the water during distillation.
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i want to find the proper catalyst to improve the reaction in esterification . |
You are familiar with the basic methods of driving an esterification? Like azeotropical distilation of the produced water with toluene?
Also, I understand that English is not your first language, but please make an effort, this will only benefit yourself. Use a browser like firefox
with a built in spellchecker or type your posts in microsoft word first for example.
[Edited on 27-9-2008 by vulture]
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Sauron
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You might want to look carefully at the toxicity of this acid and its salts. Monofluoroacetic acid is extremely toxic and its alkili metal salts are
used as rat poisons. I have never encountered difluoroacetic acid, unlike trifluoroacetic acid, and I do not know what its toxic properties might be.
TFA is extremely irritating and corrosive, of course as well as volatile. If I were going to make what you are making I would want a very close look
at the literature beforehand. ''Just a word to the wise.
Saunders gives a detailed account of toxicity of many fluoroacetate salts and esters in his book which is available in the forum library for free
download.
As far as I know there is no antidote for fluoroacetate poisoning; death is by convulsions.
Sic gorgeamus a los subjectatus nunc.
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not_important
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Difluoroacetate is much closer in its toxicity to TFA than to MFA. It's still somewhat toxic, chronic exposure has been linked to nerve and liver
damage.
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panziandi
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Indeed MFA is incredibly toxic and by no means limited to rat poison! Its the ingredient in the infamous 1080 bait used in australia and used to kill
many pests (wild dogs especially). It has no antidote and knocks out the Kreb's cycle!
TFA is incredibly irritating, fumes densly in air and not very nice to work with really. I'd imagine DFA is similar.
The method I would choose personally myself, would be to obtain the sodium or potassium salt and distil that from concentrated sulphuric acid in all
glass setup chilling the receiver with ice, and obviously in a fume cupboard!
If your starting compounds are the esters or amides go for alkaline hydrolysis with NaOH or KOH then isolate the Na or K difluoroacetate. Dry this by
simply heating it (I suppose to fusion would be ok). Then powder it, add conc H2SO4 and distil the DFA from this as above.
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