MKSStal
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Quaternary ammonium salt from triethanolamine
For me typically used triethylamine is barely accesible. So I thought about reacting triethanolamine (HOC2H4)3N with
some alkyl halide to make quaternary ammonium salt. Do you think it will work or halide will rather attack oxygen atoms forming ethers?
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Nicodem
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Thread Moved
22-10-2015 at 10:02 |
MKSStal
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So in my opinion it depends on which alkyl halide would be used. For 1' reaction with alcohol shouldn't take place, for 2' might and for 3' would be
probably great problem
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deltaH
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You might also consider oxidising the triethanolamine with Caro's acid to form salts based on the protonated amine oxide or hydroxylammonium cation,
i.e. (HOCH2CH2)3N[+]-OH.
[Edited on 25-10-2015 by deltaH]
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MKSStal
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Caro acid won't also oxidise hydroxyl groups to aldehydes or rather carboxilic acids?
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deltaH
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I'm not sure which would occur faster.
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Pumukli
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My two cents:
I would try something between methyl- to butyl-iodide. I mean the first four primary iodides may have chance to alkylate the N.
(N being more nucleophylic than O usually and primary alkyls having the least steric hindrance, though beyond 4 carbon in the chain the steric effect
probably would be too strong and prevent alkylation.)
If it worked you may still ran into problems because of the OH-s in the molecule though. These OH-s would surely affect the phys-chem properties of
the molecule and may react in the reaction where you used this salt. (Roughly: tetraethyl-ammonium-X and tetraethyl-beta-OH-ammonium-X are not the
same.)
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byko3y
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MKSStal, look for neutral desinfection liquids, they contain quaternary ammonium chlorides.
Triethanolammonium is a no way to quaternary ammonium. Also, even if you have managed to prepare quaternary ammonium from triethanol amine, it would
not have the necessary PTC properties of quaternary ammonium salts.
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MKSStal
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So, I tried to test it. On Tuesday I mixed about 13,2 ml (0,1 mol) of triethanolamine with 11,5 ml (0,1 mol) of benzyl chloride. BnCl I made myself by
reacting benzyl alcohol with hydrochloric acid. It was quite old sample, so it might contain some water in it. More probably because I haven't
purified it by destilation. And it has yellow colour (just after being created it was violet). I mixed it in 50ml Erlenmayer flask, capped and left to
react. After about 3 hours large mass of crystals have participated out. I left it to let the reaction come to the end (I thought that after the
reaction all liquid should convert into crystalline mass). And until today (Friday afternoon) nothing much changed. Crystalline mass and yellow liquid
above it. I decanted that liquid into test tube and heated for a while. Nothing happened even after cooling. However, by this operation I was able to
observ that crystals are colourless. Mass left in flask still is very wet so I'm thinking about adding some hexanes to it.
So I think that due to my experiment this reaction works but yield should be improved.
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