I agree with Prof. Frank T. Edelmann

Dear Onyinye Uwaezuoke, in this case I would suggest to try the crystallization by a slow diffusion technique, i.e. you could prepare a solution of your compound in THF in a small vial and then place the vial with the solution in a larger closed glass container with a low-boiling less polar solvent such as diethyl ether or pentane. Slow diffusion of the latter into the vial will most likely produce good crystals. Alternatively you could carefully layer the THF solution with pentane using a pipette.

Dear all, would you please tell what have you done so far that the crystallization bacame a problem? Have you tried saturation by slow evaporation, or freezing or even freeze drying?

The following document deals with similar situation with different amines salts. My Regards

https://link.springer.com/article/10.1007/BF02640269

Dear Onyinye,

As Prof. Edelmann pointed out correctly, you should slowly add to your THF solution a low polarity solvent by diffusion or condensation. I recommend diethyl ether or n-pentane. Appended you will find a slide of my lecture iluustrating the technique.

All the best for your research,

Thomas

here is the slide..

Dear Thomas Jüstel, the picture you provided should very useful to answer a number of closely related question on RG as well. 👍

Dear Onyinye Uwaezuoke ;

I suggest you try the two-solvent crystallization technique. Complete information on the solubility of the substance as a function of the anti-solvent concentration is required prior to crystallization. There must be a significant difference between the solubility of the molecule in the solvent and in the anti-solvent. In addition, in this process, material transfers, mechanical factors and kinetic phenomena compete to produce crystals. The efficiency of crystallization is lower at a temperature lower than the boiling temperature of the solvent. Cooling should be as slow as possible; otherwise crystals may not have time to form or may grow too quickly and may retain impurities. The co-solvent (Solvent 2) should be added slowly until a slight haze (supersaturation) occurs.

With my best regards

Dear all, the suggestion presented by Dr. Thomas Jüstel may be valuable if the structure of the amine is given in the question. All What is said it is an amine, obviously it is a substituted amine, this substituting group may enhance more the solubility in the New combination of solvents mixture, rendering the crystallization impossible again. My Regards

Thank you, Frank T. Edelmann and Thomas Jüstel Your suggestions are very helpful. I will try the solvents you suggested. Thank you Abdelkader BOUAZIZ and Doufnoune RACHIDA Rachida Your suggestion about the substituent group may have affected the crystalization in hexane. Thank you all for your help

Nice question Onyinye Uwaezuoke

I agree with Prof. Frank T. Edelmann Thomas Jüstel Abdelkader BOUAZIZ Doufnoune RACHIDA Rachida. I remember I have a similar case once upon a time and I followed the procedure they mentioned. i.e. completely dissolve your salt in less amount THF, then add by a pipette drop by drop very slowly diethyl ether or pentane or hexane. You notice in every addition formation of turbidity then continue until you obtain your pure compound settling in the bottom (after removing the solvent you can pick it up).

N.B. the turbidity is an indication of the formation of tiny pure crystals. If no turbidity occurs, then stop as you perhaps did something wrong.

Best Wishes

you must try the two-solvent crystallization technique.

Thank you, everyone, for your kind contributions Salim jasim Mohammed Mohammad Hegazy , and others

Crystallization of a new substance from THF as a solvent depends up on the nature and polarity of tour compd. THf is a volatile solvent , so dissolve compd. in THF by warming on water bath (do not use burner) , On slow cooling the compd. will come out in crystalline form..

Onyinye Uwaezuoke in the meantime, have you been able to successfully crystallize your new substance?