Crystal Reconstruction: Methods and Possibilities

  • Thread starter Thread starter JG89
  • Start date Start date
  • Tags Tags
    Crystal
Click For Summary

Discussion Overview

The discussion revolves around methods for reconstructing crystals from powdered forms of substances, exploring the impact of solvents and conditions on crystal appearance. It includes theoretical and practical considerations related to crystallization processes and the challenges faced in achieving desired crystal forms.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest dissolving the powdered crystals in a solvent and evaporating the solvent as a method for reconstruction.
  • Others propose melting and cooling the substance as an alternative approach to achieve crystallization.
  • It is noted that the appearance of crystals can be influenced by the choice of solvent and the conditions under which crystallization occurs.
  • One participant shares specific experiences with a compound that forms opaque, pearly crystals when crystallized from diethyl ether, but results in transparent crystals when using methanol or isopropyl alcohol, raising questions about how to replicate the original appearance.
  • Another participant suggests neutralizing the hydrochloride and recrystallizing by adding HCl, while cautioning that this method may not guarantee the same results.
  • Concerns are raised about the implications of different crystal forms in pharmaceutical contexts, including regulatory issues related to product approval.

Areas of Agreement / Disagreement

Participants express varying opinions on the best methods for reconstructing crystals and the factors affecting crystal appearance. There is no consensus on a definitive approach or outcome.

Contextual Notes

Participants mention the unpredictability of crystallization outcomes based on solvent choice and other variables, highlighting the complexity of the process and the potential for different crystal forms to arise.

JG89
Messages
724
Reaction score
1
Suppose I have a substance that has been crystallized. Now suppose I break down those crystals into powder, grains, etc. How can I reconstruct that powder into a crystal again? Do I just dissolve it into a solvent and then evaporate the solvent?

Another quick question - is it possible to manipulate the appearnace of the crystal based on what solvent I use, the amount of solvent I use, etc?
 
Chemistry news on Phys.org
JG89 said:
How can I reconstruct that powder into a crystal again? Do I just dissolve it into a solvent and then evaporate the solvent?

Either that, or melt and cool down to solidify.

JG89 said:
is it possible to manipulate the appearnace of the crystal based on what solvent I use, the amount of solvent I use, etc?

Let me put it this way - crystal form can depend on the solvent used and/or other substances dissolved. I have heard organic chemists say "If you have not seen other crystalline forms of your substance, you have not tried hard enough". Those working in pharma told me horror stories about products that were approved for use, but one day started to crystallize in another form and they were unable to find the reason (and as far as I know you can't sell different form, you have to sell the one you have permission for). But it is not easy to predict.
 
To be specific, the compound the I am trying to crystallize is usually comprised of nearly opaque, pearly crystals. When it is in its base form, it is dissolved in diethyl ether, then precipitated in its hydrochloride form by adding an acetone/HCL acid solution (or by bubbling dry HCL gas through the solution). This results in opaque-ish, pearly crystals. My problem is, if I were to break these crystals down and reassemble them by crystallizing them in, say, methanol (or IPA), the result is transparent crystals which bear no resemblence to the original crystals. How can I reassemble the crystals so that they look the same as the original?
 
The most logical approach would be to neutralize the hydrochloride and recrystallize by adding HCl (that is, by repeating the same procedure). Note it is not guaranteed to work.

What do you need these crystals for? If you are getting clear ones they are probably 'better' - less inclusions and impurities.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 2 ·
Replies
2
Views
6K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 3 ·
Replies
3
Views
929
Replies
0
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 19 ·
Replies
19
Views
1K
  • · Replies 1 ·
Replies
1
Views
16K