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Author: Subject: Work in nitrogen?
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[*] posted on 18-11-2005 at 15:54
Work in nitrogen?


"A n L reactor was charged with something-something (x gr.) and water (y mL) under nitrogen"

Does that mean I have to work in a oxygen-free atmosphere? Correct me if I'm wrong. :)

Thanks in advance!
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[*] posted on 19-11-2005 at 03:09


Well, maybe it's not a beginner question, I hope someone who have more practical experience than me can help me.
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[*] posted on 19-11-2005 at 05:21


Maby if you told us exactly what reagents this reaction uses, we could tell you how necessary is the oxygene free atmosphere...

In some cases you can load your reactor with everything but the oxygene sensitive compound. Then flush reactor with nitrogen, add the oxygene sensitive compound fast, and finally flush with nitrogen again.
In other cases, where absolutely no oxygene is wanted, theres other techniques..
Again, it depends on reagents.

Note that in some journals people do reactions under nitrogen while it's not really necessary (methodics are rarely optimized so to say..).
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[*] posted on 19-11-2005 at 06:17


Okay, you can have the full reaction then:

A 2 L reactor was charged with diphenylmethylisothiouronium bromide crude wet obtained (240 gr.) and water (700 mL) under nitrogen. The suspension was heated to 60°C and 46% aqueous NaOH solution (98 ml, 1.68 mole, 2.4 eq.) was added.

Does it make sense then?
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[*] posted on 19-11-2005 at 10:59


Googled up this strange "diphenylmethylisothiouronium bromide" and found the patent with the procedure..

Huh, nope, it doesn't make sence. I thoat from beginning you had some transition metal catalysed reaction.. The nitrogen atmosphere seems to be an excessive precaution..

If I got it correctly, they first release the sulfite:

Ph(Ph)C-S-C(=NH)NH2*HBr -NaOH-> Ph(Ph)C-S-

and then react it with chloroacetamide:

Ph(Ph)C-S- + Cl-CH2-CONH2 -> Ph(Ph)C-S-CH2-CONH2

IMO, these are not oxygene sensitive compounds nor reactions. Anyone correct me if I'm wrong..
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[*] posted on 19-11-2005 at 14:04


I can afford to try without nitrogen, so maybe I'll just do that and see what happens :)
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