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Author: Subject: Nitrostyrene reduction using NaBH4/CuCl2
S.C. Wack
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[*] posted on 27-10-2019 at 19:00


(M)ethyl alcohol will not form a separate layer with NaOH. IPA will not form peroxides not already present when distilled or evaporated in vacuo, and I would think that peroxides in solvents would either decompose, not form, or react with other things when evaporated with many other cpds. besides the solvent. BTW it is said that even ethers full of peroxides can be distilled to dryness uneventfully if the heat source is not too strong.

[Edited on 28-10-2019 by S.C. Wack]




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[*] posted on 28-10-2019 at 13:50


Quote: Originally posted by horribilis  
Quote: Originally posted by S.C. Wack  
Not sure why you have to get toluene involved...it should have been better to extract with IPA and evaporate.


IPA may form explosive peroxides. http://www.sciencemadness.org/talk/viewthread.php?tid=21495 I don't know if it's baseless paranoia or a valid concern when distilling to dryness? Another user has suggested peroxide test strips. Primary alcohols would be a safe solvent but NaBH4 reacts with them?

[Edited on 28-10-2019 by horribilis]


May , but not in these reaction conditions.

NaBH4 would react with the peroxide as per this paper:

https://www.sciencedirect.com/science/article/abs/pii/S03603...



Quote:

but the crystals are dirty and don't clean up very well even with recrystallization -- this is why I would like to vacuum distill the freebase amine.


There are other ways to clean amines. Use one of this method.

You can also check the purity by tlc with 2 different solvent systems and stains. Compare the 2 against each other. If u get 1 single spot you are good.

Shulgin distilled at 120-130 °C at 0.3 mm/Hg. If you are pro using such high vacuum then this is the way.
IMO distillation can be replaced with other purification methods.


[Edited on 28-10-2019 by Mush]
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horribilis
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[*] posted on 28-10-2019 at 16:07


Quote: Originally posted by Mush  
Quote: Originally posted by horribilis  
Quote: Originally posted by S.C. Wack  
Not sure why you have to get toluene involved...it should have been better to extract with IPA and evaporate.


IPA may form explosive peroxides. http://www.sciencemadness.org/talk/viewthread.php?tid=21495 I don't know if it's baseless paranoia or a valid concern when distilling to dryness? Another user has suggested peroxide test strips. Primary alcohols would be a safe solvent but NaBH4 reacts with them?

[Edited on 28-10-2019 by horribilis]


May , but not in these reaction conditions.

NaBH4 would react with the peroxide as per this paper:

https://www.sciencedirect.com/science/article/abs/pii/S03603...



Quote:

but the crystals are dirty and don't clean up very well even with recrystallization -- this is why I would like to vacuum distill the freebase amine.


There are other ways to clean amines. Use one of this method.

You can also check the purity by tlc with 2 different solvent systems and stains. Compare the 2 against each other. If u get 1 single spot you are good.

Shulgin distilled at 120-130 °C at 0.3 mm/Hg. If you are pro using such high vacuum then this is the way.
IMO distillation can be replaced with other purification methods.


[Edited on 28-10-2019 by Mush]


I did not think of that -- it now seems obvious that that a >6 molar excess of NaBH4 would reduce peroxides. :)
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