January 24, 2021, 07:26:22 AM
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Topic: Is there a way to isolate aliphatic amines from aromatic and heterocyclic amines  (Read 585 times)

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Offline dulg

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I know that the key distinction between the two (three) are their structures, and that they are classified by their structures, but I am wondering if there is a way to isolate the two using solvents. I am not an expert in this field, and would love to get some help.

I know that asking for a magic solvent to solve all of my problems is a very naive, so please forgive me for asking this.

Many Thanks,

Offline hollytara

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You might be able to use acid-base properties.  Most aliphatic amines are much more basic than aromatic amines. 

So at a pH of say 8-9, the aromatic amines will not be protonated and will go into an organic solvent, the aliphatics will still be protonated and will dissolve in water

Offline wildfyr

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Hollytara, thats an oversimplification... some percentage of each amine will be protonated at an intermediate pH, but the ratios will change with pH. If the pKbs are 3 units apart then perhaps you could do this with minimal crossover. I think separating a mixture this way would be pretty hard. Have you ever tried it?

Distillation strikes me as a better way to do it depending on the exact amines.

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