I was synthesized potassium salt of organic copound. Then recrystallized in methano/ether. How can I remove KOH from crystal as my compound is soluble in methanol and water. Any other organic which can dissolve KOH?
Dear Atif Ali ,
In this case, If you get an unreacted reactant of organic starting material, you can extract your material with water and ether utilizing a separating funnel. store the aqueous layer and Ignore the ether layer. Then, evaporate water in order to obtain the final potassium salt of the organic compound in pure form.
But If you want to convert a crystal of your organic potassium salt to a corresponding organic compound, It is easy to neutralize with a dilute solution of HCl acid and then extract your material with water and ether utilizing a separating funnel. Ignore the aqueous layer and store the ether layer. Then, evaporate ether in order to obtain the final of a new corresponding organic compound in pure form.
Best regards
You can avoid the excess KOH from beginning by using mole ratio reactant to KOH 1:0.8 or less ,in this case no unreacted KOH but there is unreacted reactant which is soluble in lass polar solvent, is it easy to remove.
Dear Atif Ali ,
In this case, If you get an unreacted reactant of organic starting material, you can extract your material with water and ether utilizing a separating funnel. store the aqueous layer and Ignore the ether layer. Then, evaporate water in order to obtain the final potassium salt of the organic compound in pure form.
But If you want to convert a crystal of your organic potassium salt to a corresponding organic compound, It is easy to neutralize with a dilute solution of HCl acid and then extract your material with water and ether utilizing a separating funnel. Ignore the aqueous layer and store the ether layer. Then, evaporate ether in order to obtain the final of a new corresponding organic compound in pure form.
Best regards
Hi Atif,
Try to follow this: dissolve your KOH containing material in MeOH, then saturate the solution with CO2. If you are using a large excess of MeOH, the situation is a little more complicated. Add solid KHCO3 and remove as much as possible the MeOH.
If you worry about the conversion of your organic salt to acid, then move a step back. Dissolve all the materials in water, add some KHCO3 to convert KOH to carbonate and extract the aq. solution with e.g. CH2Cl2, CHCl3, or toluene (depending on your solubility data). Then remove the solvent, and dissolve your compound in MeOH containing solid K2CO3. Stir or sonicate until all your compound is converted to K-salt.
If your compound is unstable (e.g. because the potential esterification by MeOH is disturbing, etc.) or you cannot perform the extraction above, you can remove the mayor part of K by HCl addition. Then (when the pH is little acidic, ~6-7; please remember that in MeOH solution, the pH is always a little lower than in water) add K2CO3 powder and stir/sonicate.
Filter the solid which is K2CO3/KHCO3 (using HCl, KCl also), and the MeOH solution will contain only your organic compounds.
Good luck,
Laszlo
Hi Atif Ali, In your case, there is another choice, try to convert the KOH to another salt which is insoluble in water by utilizing suitable metal oxide.
Dear Atif,
If even the CO2 is too acidic, you can use also NH4Cl. The KOH is converted to KCl and slight warming eliminates ammonia. The NH4Cl is also poorly soluble in MeOH, so the inorganic salts are easy to remove.
And use a lab US-cleaner for better contacts. The only problem that within 10-15 min the water bath becomes warm (30-40oC), and you need to change the water. You may put ice into he US bath then you can sonicate your solution for ~30 min or more.
Good luck,
Laszlo
Potassium hydroxide is soluble in ethanol, phenol, and glycerol; and their aq. solutions. Insoluble in diethyl ether.
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