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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Peacock on August 04, 2010, 04:37:57 AM

Title: Quantitative precipitation of formic acid
Post by: Peacock on August 04, 2010, 04:37:57 AM

Dear All,

I am struggling to find a reagent that causes the quantitative precipitation of carboxylic acids, especially formic acid.  ???

It sounds like a textbook question, but I cannot find any. Could anybody with better knowledge give me a hand in this issue?

Regards

Title: Re: Quantitative precipitation of formic acid
Post by: Stepan on August 04, 2010, 09:43:10 AM

To the best of my knowledge all salts of formic and acetic acids are highly soluble

Title: Re: Quantitative precipitation of formic acid
Post by: discodermolide on August 04, 2010, 11:45:04 AM

Try a barium salt if you want it inorganic, otherwise use an organic amine, dicyclohexylamine for example.

Title: Re: Quantitative precipitation of formic acid
Post by: Stepan on August 04, 2010, 05:11:14 PM

Barium Formate and Acetate are soluble in water (>25g/100g). 

Title: Re: Quantitative precipitation of formic acid
Post by: Peacock on August 06, 2010, 01:53:15 PM

Thanks for your replies.

I intend to get rid of formate (formic acid) in aqueous solution at room temperature and also at pH 7.

I thought of precipitation as the most likely means of doing it. However, given your replies, I am wondering if there are other reactions formate can undergo in the above-mentioned conditions.

Could you come up with any?

Thanks

Title: Re: Quantitative precipitation of formic acid
Post by: Peacock on August 06, 2010, 01:59:19 PM

I forgot to mention that there is formaldehyde as well in the solution, and CO2, therefore I am not after a redox reaction. But of any other type.

Regards

Title: Re: Quantitative precipitation of formic acid
Post by: Stepan on August 09, 2010, 09:07:21 AM

Depends on composition, volume as well as application, you can neutralize the solution and distill it into another vessel.

Title: Re: Quantitative precipitation of formic acid
Post by: Peacock on August 09, 2010, 11:19:54 AM

Right...

Isn't there a way to transform the formate (formic acid) without oxidizing or reducing it on the spot? without further processing?

I didn't know it would be so complicated... :(

Title: Re: Quantitative precipitation of formic acid
Post by: Stepan on August 10, 2010, 01:37:24 PM

If you give us a better idea what you are trying to achieve (full picture), we might be able to find a solution. 8)