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Author: Subject: Post reaction separation
Muzz1969
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[*] posted on 1-2-2015 at 03:47
Post reaction separation


I have been fooling around with electrolysis cells lately and have been oxidising primary alcohols with Br2. After distilling most of the bromine off post reaction, I am still left with a tinge of yellow in the solution. My question is what would be the best way to precipitate the rest of the Br out of the solution. I have been oxidising ethanol and methanol so far.
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gdflp
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[*] posted on 1-2-2015 at 05:46


The standard way of removing traces of bromine is to add a reducing agent such as sodium metabisulfite, sodium thiosulfate, sodium sulfite, etc. The one I've seen used most commonly is metabisulfite.
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Muzz1969
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[*] posted on 1-2-2015 at 05:50


Quote: Originally posted by gdflp  
The standard way of removing traces of bromine is to add a reducing agent such as sodium metabisulfite, sodium thiosulfate, sodium sulfite, etc. The one I've seen used most commonly is metabisulfite.


So would that precipitate into sodium bromide or sodium bromate
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[*] posted on 1-2-2015 at 06:04


Sodium bromide, 2Na2S2O5 + Br2 --> 2NaBr + Na2SO4 + 3SO2
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blogfast25
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[*] posted on 1-2-2015 at 06:29


Quote: Originally posted by Muzz1969  
I have been oxidising ethanol and methanol so far.


Oxidising them to what?




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Muzz1969
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[*] posted on 1-2-2015 at 06:46


Quote: Originally posted by blogfast25  
Quote: Originally posted by Muzz1969  
I have been oxidising ethanol and methanol so far.


Oxidising them to what?


Ethanoic acid , it is usually done in solution with dichromate but I'm fooling around with a cell and other metals such as bromine to see what happens.
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blogfast25
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[*] posted on 1-2-2015 at 08:22


Quote: Originally posted by Muzz1969  
Ethanoic acid , it is usually done in solution with dichromate but I'm fooling around with a cell and other metals such as bromine to see what happens.


Metals such as bromine?

Oxidising ethanol to ethanoic acid with bromine? Bromine is unlikely to have anything near the oxidising power needed for that oxidation.

So maybe that's where the 'fooling around with a cell' comes into it. Explain?

[Edited on 1-2-2015 by blogfast25]




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[*] posted on 1-2-2015 at 19:36


@ blogfast ....as I said I'm fooling around with only my instinct and what I read to guide me. I start uni in a few weeks so my formal learning will start there. I am really interested in electrochem and have started building a few different cells in different configurations to see what produces better results for organic reactions. The only chemicals I can get my hands on at the moment is ethanol, methanol and tetrahydrafuran so I started playing with the ethanol. Of course any input to guide me in electrochemical reactions would be appreciated.
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