Thank you Dr. Salih
Started using nonpolar solvent for example cyclohexane , ether.
And another shoose using polar solvent
It is much easier to dissolve it in dry methanol and add a a non solvent such as water. Some times even by suspending in dry EtOH/MeoH will result in powder solid of the product. This process is well known in organic synthesis to bet a sold product from a gum/oily material and is known as trituration.
The second alternative is to pass through dry silica or alumina column with suitable solvents.
Please try first with a small ammount of your sample.
Use e.g. dry ethyl ether; if it dissolves the whole sample it is not suibtabe. Try another one. The appropriate solvent will dissolve the greasy material and leave your compound in the solid state. Then filter and purify it by the usual appropriate techniques.
Choose that solvent in which the reaction will proceed and after workup it will easily mix (or miscible) with the solvent choosen for workup and thus will leave the product easily.
For example..... We have a reaction mixture containing DMSO solvent. TLC observations indicating the completion of reaction. So just go for workup. Take water (almost 4 to 5 times more in volume to that of reaction mixture) in a beaker and add the reaction mixture to it with stirring and you will get your product because DMSO is water miscible and thus leaves the organic compound dissolved in it.
Further about gummy product....These are some things strikes directly to my mind after reading your query. May be it will help you...
(i) your desired compound contains impurity....... If no then
(ii) your desired compound have low melting point.... If no then
(iii) if extracted, your desired compound contains solvent (solvent trap)...If no then
(iv) your desired compound may be gummy in actual or say in real.... If no then
I really dont know why it is so.
(Please let me know any other thing regarding it if you know)
I think the fundamental requirement is a solvent that dissolves the responsible impurities but is a weak solvent for the desired product. I had most success with diethyl ether at one end of the spectrum, and methanol at the other end. You can add hexane or water, respectively, and use an ice bath, to push the limits of solubility.
Filtration through a short column of silica, as suggested by Sengottuvelan, is very effective at taking out hygroscopic salts.
It is true as James has indicated. The polarity of the solvent plays a crucial role. Initially the solubility has to be checked with a small quantity of the product before trying to solubilize the entire mixture.
Dear Salih, thanks for sharing this interesting technical problem on RG. In fact, this is a very common problem which virtually all organic chemists face from time to time. Countless crude products are first isolated as oils. However, without knowing exactly what type of compound you are dealing with, it is a bit difficult to suggest to you the right method. For example, in carbohydrate chemistry it is quite normal that even rather pure products are oily or syrup-like. The first thing I would do in your case is heat the product under high vacuum at slightly elevated temperatures (e.g. 40-60 °C) in order to remove residual solvent as much as possible. Then you could e.g. dissolve it in methanol and precipitate it again by adding diethyl ether (of course the solvent combination depends on the nature of your compound). For less polar products the combination of e.g. toluene and n-pentane could also be the right solvent mixture. Sometimes it also helps to triturate (stir) the gummy product with a solvent in which it is virtually insoluble (diethyl ether, n-pentane etc.). Scratching the mixture with a glass rod can induce the formation of seed crystals. That way you should be able to obtain a solid material.
Good luck with your experiments and best wishes, Frank Edelmann
Dear Omar, Frank, Sengottuvelan, Abel, Amit, James, and Palansamy, I am very gratefull for your answers .I have got the solid product by use of washing with petroleum ether then, decantation, dissolved in ethanol .adding crashed ice give cloudy solution which left over night to give solid precipitate.
Nice to know that Salih was able to get the solid product
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