I would suggest you to confirm the solubility of your product (aqueous or organic). If your compound is significantly soluble in organic solvent then you can use either of the options you mentioned. If you feel your compound has more affinity towards water then its better to proceed with the second method. In addition, you can also filter the potassium carbonate and purify the organic layer using column chromatography. This method may furnish your compound in lesser time compared to the second option you have discussed.

Best wishes,

I would suggest you to proceed with the second method. 

I think that depends on your solvent system of your rxn, İf your rxn mixture is on volatile organic solvent (DCM, THF, Ether, MeOH, EtOAc, AcCN etc) and you are worried that you might lose the product then definitely 2nd option. Once you remove the solvent use any organıc solvent to load on column that won't dissolve K2CO3. However, if you are running your rxn in DMF or DMSO then you need to get rid of the solvent and inorganics before you plan on SGC. So the answer is depending on your rxn solvent. Hope this helps and good luck.

First have to go through recrystallization, solvent extraction if compond not separable (trial and error method on the basis of polarity of them Or triangle way prediction )and finally it is only option to select chromatography viz. column, HPLC as choice of columnn and mode are important....

1)  Extraction in organic solvent followed by aqueous  wash to remove the K2CO3. Again go for acidic & Base wash to remove impurities & precipitate by anti solvent  or crystallize.

2) If the compound is soluble in methanol , make it soluble in min amt of MeOH then filter the potaasium carbonate.Evaporate the solvent go for crystallization to remove impurities

3) Lastly go for column chromatography as the K2CO3 will be in fine powder it will stick hard to column for the elution of mobile phase.

I concur with Kachapur's comments.  If you can't recrystallize your product, then check the reaction mix by TLC to determine which organic solvent or solvent system affords the greatest difference in retention factors for the components to maximize the effectiveness of the chromatographic separation.

My suggestion depends on which solvent the reaction is performed in. If it is an aqueous solution, or DMF, DMSO, DMPU or a similar high boiling solvent then you must remove it before chromatography over silica gel - the best method being separation of the K2CO3 in with water or dilute acid, and then extraction of your compound into a solvent such as dichloromethane or perhaps ethyl acetate. The second method should be fine if you have a volatile solvent that you can simply evaporate to get the crude product. Then simply dissolve in your desired chromatography solvent and load onto the column.

I think second method, but after filtration.

Precious little information for the good advice.

You can first filtrate all the mixture thruoght the SHORT column (or glass filter) with a small quantity of silicagel. May be wash the SiO2 with a polar solvent. By this way You will pre-pyrify the substance and do NOT make your main purifying column too durty. Ather such filtration evacuate the solvent and run the column chromatography as it have to be.

I suggest to filter your reaction mixture first to remove any excess of potassium carbonate, then perform a column chromatography after you found best eluent by TLC of the crude.

Dear Tahseen Iqbal

I think that potassium carbonate is best to wash with water. If your impurities are polar, I need to understand to what extent? If they are able to dissociate in highly polar solvents, it is possible to use ion exchange processes on cation exchanger and anion exchanger.

But it needs to know exactly what kind of a substance or substances specifically in question.

Sincerely Professor Pavel Kudryavtsev

If your compound is polar enough to go into water - filter through a short plug of Celite  545 (diatomaceous earth). That would be better than silica because there is almost no change that your compounds will stick to it. Then rotovap and do your column.

If your desired compound is not water soluble, I would do a water wash first. I dislike filtering through Celite. It just takes so long. I just rotovap everything down, wash with water and then do the column.

Do not take everything and put it on the column. You run the risk of your column getting clogged up by the K2CO3 residue. Then your column could burst/ pressure get too high/ its a mess, save yourself the trouble.

In general, if you are working with particularly polar compounds it is a good idea to avoid aqueous work ups.

If your crude reaction mixture is potassium carbonate, organic polar compound (the required one) and some polar but possibly organic impurities then it is presumably some sort of solid paste? i.e. no solvent or water?

If so, just triturate the sample with DCM, THF or some other solvent which K2CO3 is insoluble in: Add some DCM, sonicate, stir etc. then decant or pippette the solvent leaving the K2CO3 behind. Three times is generally sufficient. you can then concentrate the washings in vacuo and subject the residue to chromatographic separation. Uses less glassware than filtering.

If you do have a solvent then it is likely that the K2CO3 is insoluble, so just filter it then evaporate in vacuo and column the residue.

Dear Tahseen Iqbal 1.10

Try to extract your  product  in organic solvent like diethyl ether or methylene chloride. By this, you will remove the  potassium carbonate, and then you can perform column chromatography after you found best eluent by TLC of the crude.

Good luck

Prof. Dr. Talaat El-Emary

Hi. How can I make a Schiff base from Urea and amine? Please help me- Yhanks a lot

If your product is soluble in organics, then go ahead with the aqueous solubility/filtration path to get rid of the K2CO3.

The second possibility that should be answered is the following; assuming that your product is soluble in water, then it would not be possible to go through a typical DCM:ddH20 type of an extraction and/or dissolving the product material in DCM to insert it into a normal phase column that's going to have a standart EtOAc:Hex solvent system. This type of approach would not work. Instead what you can do is to run a column with Acetone:Hex solvent system, your product will still be in the mobile phase, ride along with the Acetone through the column while K2CO3 sticks on the silica. If you play with the solvent ratios correctly, you can get rid of the undesired reactants/impurities with very well efficiency since Acetone:Hex solvent is quite similar to a EtOAc:Hex solvent system.

I would recommend the acqueos extraction followed by column cromatography

You could also directly apply your sample on column chromatography but I feel the double step putification is easier and more easy to handle

Regards

You may decide your workup procedure on the basis of nature of reactant and product. Suppose if your performing peptide reaction using acid and amine. After confirmation of peptide formation by TLC, either carboxylicacid or amine unreacted starting material may left! that you decide by using either 1N HClwash or 1N NaOH wash depending upon the carboxylicacid or amine.