[barnabe]

Hi,

I make a pyridine salt which contains the pyridine and an organic weak acid. The standard procedure to isolate the acid and remove the pyridine is to dissolve the salt in Diethyl ether with HCL, and let the diethy ether evaporate, which leaves the organic acid crystals with purity 99%.

But i would like to use something else, less flammable than ether to isolate the said acid.
Do you have any idea what could be used?
The acid is composed of C H O and is completely insolube in water. It is mildy soluble in alcohols and quite soluble in dichloromethane.

Thanks for any motivated suggestion.

Regards

[Illuminatus]

Hi barnabe,

Look up THF (tetrahydrofuran), it may suit your needs.

Enjoy

[discodermolide]

Where does the pyridine go? By this procedure, that you posted, you have not removed it.

[barnabe]

Hi, it s washing + evaporation in effect:

The  pyridine salt  isdissolved in ether and shaken with aqeuous HCl. The ether solution is then washed with water , dried and evaporated to give the compound.


As said, i d rather use another solvent than ether (no fume hood in my settings).
Any idea?
Thanks

[camptzak]

Hi, it s washing + evaporation in effect:

The  pyridine salt  isdissolved in ether and shaken with aqeuous HCl. The ether solution is then washed with water , dried and evaporated to give the compound.


As said, i d rather use another solvent than ether (no fume hood in my settings).
Any idea?
Thanks

thf is a good idea, what solvents do you have access to? you should try to find some sort of hood or protective area.... as yoda would say; very dangerous organic solvents are

[magician4]

If my analysis of your described procedure is correct, for the time being after addition of aq. HCl you will have a 2-phases system, with pyridine x HCl in the aqueous layer, and the pure acid in the etheric layer.

phase separation and removal of the ether gains your product


replacing diethylether with THF in this case will FAIL , as THF is highly miscible with water
--> no phase separation


methylenchloride might be the better alternative (with respect to flammability), though I would suggest a hood nonetheless, due to its adverse health effects


regards


Ingo

[barnabe]

Hi,

thanks for your responses. In effect i will try Dichloromethane as it has regarding to my specs comparable suitability to ether for miscibility, with the different other solvents/compounds.

I could also try ethyl acetate.

Best regards and thanks