Beryllium
Harmless
Posts: 6
Registered: 23-10-2007
Member Is Offline
Mood: No Mood
|
|
Synthesis of TMAOH
I'm intending to use it as a surfectant for ferrofluid, and I am wondering if there is a feasible way to synthesize tetramethylammonium hydroxide.
My thoughts so far were to bubble NH3 gas through water to obtain NH4OH until saturation, add methanol, and then recrystallize out the (hopefully)
TMAOH.
I've no idea if this would work, or if it would what to catalyze it with.
Any suggestions?
Oh, and happy Mole Day.
|
|
|
solo
International Hazard
Posts: 3975
Registered: 9-12-2002
Location: Estados Unidos de La Republica Mexicana
Member Is Offline
Mood: ....getting old and drowning in a sea of knowledge
|
|
Reference Information
Tetramethylammonium hydroxide
James Walker and John Johnston
J. Chem. Soc., Trans., 1905, 87, 955 - 961,
Excerpt
...........Practically the preparation of tetramethylammonium hydroxide fiom its salts resolves itself into a question of solubility as
follows. In general, the equation NMe,X + MOH = NMe,OH i MX will represent a real action proceeding nearly to completion if N, X, and the
solvent are so chosen that all the substances except MX shall be soluble, or at least that MX shall be much less soluble than either of the
original reacting substances. This principle was applied by Hofmann in his preparations with water as solvent. For M and X he chose either the
pair Ag,I or Ba,SO,, in both of which cases MX is practically insoluble in water.
Attachment: Tetramethylammonium hydroxide.pdf (428kB)
This file has been downloaded 2836 times
It's better to die on your feet, than live on your knees....Emiliano Zapata.
|
|
|
smuv
National Hazard
Posts: 842
Registered: 2-5-2007
Member Is Offline
Mood: Jingoistic
|
|
That won't work.
If you want to start from ammonia, probably your best bet would be to methylate it (ex. with iodomethane) to obtain the quaternary ammonium halide.
Then in water treat this quaternary ammonium salt with silver oxide, which will precipitate silver halide, leaving you with a solution of
tetramethylammonium hydroxide.
Edit: solo it looks like you beat me to it. With what turned out to be an interesting article.
[Edited on 23-10-2007 by smuv]
|
|
|
Beryllium
Harmless
Posts: 6
Registered: 23-10-2007
Member Is Offline
Mood: No Mood
|
|
@smuv: What other methods could I use to methylate ammonia? I don't believe I have iodomethane or any other halomethane for that matter.
|
|
|
smuv
National Hazard
Posts: 842
Registered: 2-5-2007
Member Is Offline
Mood: Jingoistic
|
|
Unfortunately...the other alternative I can think of is dimethyl sulfate (which is exceedingly toxic, even in comparison to methyl iodide).
Do you really need tetramethylammonium hydroxide? There are a lot of quat ammonium salt surfectants in household cleaning agents. In addition
Trimethylglycine (known as betaine in health food stores) is also a readily available quat ammonium salt (although I know little about any surfactant
qualities it might possess).
One more thing, iodomethane can be prepared fairly easily from sodium/potassium iodide and methyl alcohol, using phosphoric acid to generate
hydroiodic acid in situ. Although iodomethane is a pretty toxic chemical, and fairly volatile.
I think it would take a bit of work to make tetramethylammonium hydroxide, so unless you are really heart set upon using it, I would research other
surfactants.
|
|
|
Beryllium
Harmless
Posts: 6
Registered: 23-10-2007
Member Is Offline
Mood: No Mood
|
|
There are always alternatives for surfectants, I was just investigating TMAOH as an interesting synth. Looks like it's a bit impractical though.
Thanks for the help. 
|
|
|
garage chemist
chemical wizard
Posts: 1803
Registered: 16-8-2004
Location: Germany
Member Is Offline
Mood: No Mood
|
|
Tetraethylammonium hydroxide is probably easier.
Start with triethylamine (easily bought, non-watched) and quaternize with ethyl bromide (easily made from EtOH, NaBr and H2SO4) and treat the
resulting tetraethylammonium bromide with silver oxide as described.
For tetramethylammonium ion, you would have to start from trimethylamine which is a gas (although it can be purchased as an aqueous solution) and use
methyl iodide which is seriously toxic.
|
|
|
woelen
Super Administrator
Posts: 8014
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
Is making tetraethylammonium bromide really as easy as mixing the right amount of ethyl bromide with triethylamine? No catalysts needed?
@Beryllium: Another quaternary ammonium compound which you could obtain is aliquat 336. This can be purchased commercially, albeit at a fairly high
price (I have a source for this, if interested send me a U2U). Aliquat 336 is a quaternary ammonium chloride of the form NMeR3Cl, where Me is a methyl
group, and R is either an 8-carbon chain, or a 10-carbon chain, without side branches.
|
|
|
smuv
National Hazard
Posts: 842
Registered: 2-5-2007
Member Is Offline
Mood: Jingoistic
|
|
@ Woelen, yes, It is that easy. A solvent would probably boost yields but, what you are outlining surely would produce a good bit of
tetraethylammonium bromide.
|
|
|
garage chemist
chemical wizard
Posts: 1803
Registered: 16-8-2004
Location: Germany
Member Is Offline
Mood: No Mood
|
|
Heating is needed to effect quaternization of ternary amines, but thats all.
When I made benzyltriethylammonium chloride from benzyl chloride and triethylamine in acetone, it took a few hours of refluxing until the crystals
started to separate. But the substance crystallized very nicely in well-formed needles. It was very hygroscopic though.
|
|
|
chemrox
International Hazard
Posts: 2961
Registered: 18-1-2007
Location: UTM
Member Is Offline
Mood: LaGrangian
|
|
I have to ask-what use was made of the benzyltriethylammonium chloride?
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
| Quote: | Originally posted by Beryllium
I'm intending to use it as a surfectant for ferrofluid, |
Tetramethylammonium hydroxide is not a surfactant! If you need a quat-type cationic surfactant, there is all kind of them and easily available. The
most common are the long chain quats that you can buy in aq. solution (generally 10-20%) as fabric softener.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
|
|
|
chemrox
International Hazard
Posts: 2961
Registered: 18-1-2007
Location: UTM
Member Is Offline
Mood: LaGrangian
|
|
@Nicodem "What he said" ... fabric softner, especially if it doesn't have a bunch of scent added might be suitable, they are typically loaded with
surfactant. They sell wetting agents at art supply stores too don't they? Also, landscapers use wetting agents .. so do crop dusters .. lots of
possibilities ....in fact the last might be your best bet if you need a non-ionic one. Ag supply hardware stores that handle sprays .. the wetting
agent would be cationic, anionic or non-ionic depending on the agent to be disperssed.
|
|
|
garage chemist
chemical wizard
Posts: 1803
Registered: 16-8-2004
Location: Germany
Member Is Offline
Mood: No Mood
|
|
I used the TEBAC as a catalyst for the dehydration of benzamide to benzonitrile using thionyl chloride.
A patent said that this shortens reaction time and increases the yield compared to the uncatalyzed reaction (simply heating thionyl chloride with
benzamide will make some benzonitrile, but the high temperature and long reaction time required cause darkening of the reaction mix. A 100% excess of
thiony chloride is always required though, no matter if catalyzed or not). A few drops of DMF would have done the job just as well, but that would
have generated small amounts of the highly carcinogenic N,N-dimethylcarbamoyl chloride (always forms when DMF and a chlorinating agent or acyl
chloride come together).
So I did the synthesis of TEBAC beforehand, which was my first quaternization of a tertiary amine. I was very surprised how nicely the TEBAC
crystallized.
It is very hygroscopic and extremely watersoluble though.
On the surfactant issue that this thread is about : In order for a quaternary ammonium salt to exhibit surfactant properties, at least one of the alkyl
residues on the nitrogen must be a relatively long alkyl group.
Example: Stearyltrimethylammonium chloride. The stearyl residue is C18H37. As the structure suggests it is made by quaternization of
N,N-dimethylstearylamine with methyl chloride (under pressure so that the MeCl is a liquid).
The stearylamine is made by passing stearic acid and ammonia over a dehydrating catalyst, giving stearonitrile. This is then hydrogenated to
stearylamine.
Via the Leuckart reaction, the amine group is di-methylated: formaldehyde is reacted with the amine and hydrogenated with Ni/H2 (i.e. reductive
amination). Then it is quaternized with MeCl (50- 100°C, several hours) to form the surfactant.
Many different fatty acids are used for the alkyl chain, often the mixed fatty acids obtained by hydrolysis of vegetable fats are used directly
without any separation.
So if you read the terms "cocoamine" or "tallow amine" or "oleyl amine", you know that the term means a mixture of amines with different alkyl chain
length derived from the fatty acid mixture obtained from the specific fat, and therefore a mixture of several different quat surfactants.
In Ullmann there is a table showing the alkyl chain lenth distribution in several different fats (similar, or better tables can also be found via a
google search on e.g.: vegetable fats fatty acid distribution).
For example, the fatty acids in coconut oil (from which cocoamine is derived) are comprised of the following mass fractions:
C10 and lower: 13%
C12: 41-46% (lauric acid, main component)
C14: 18-21%
C16: 9-12%
C18: 2-4%
And around 7% of C18' and C18'' unsaturated fatty acids.
So those long alkyl groups in the quat surfactants are from fat.
One could theoretically make fatty amines from fatty acids oneself as well. The pathway outlined above is only one out of many possible ones- one does
not have to go via nitrile, it is also possible and in practice to hydrogenate the fatty acids to the fatty alcohols and then alkylate dimethylamine
with them in the gas phase.
Instead of hydrogenation, the bouveault-blanc reduction (Na metal in a secondary alcohol and inert solvent, the acids are used as their methyl esters)
can be used to reduce the acids to the alcohols.
Fatty alcohols can also be produced via petrochemical routes, e.g. 2-ethylhexanol by hydrogenation of butyraldol (product of the aldol reaction of two
molecules butyraldehyde), or by oxo synthesis. Fatty acids can also be produced by oxidation of paraffin.
It could be worth trying the Hoffmann degradation (alkaline hypochlorite) on fatty acid amides to directly give fatty amines without any hydrogenation
or reduction step. The Hoffmann degradation shortens the alkyl chain by one C atom, though.
If you have mixed fatty alcohols or one fatty alcohol (e.g. cetyl alcohol (1-Hexadecanol, C16H33OH), which is readily available and cheap), you can
make a simple surfactant very easily: mix the alcohol with some concentrated H2SO4, heat gently for a while (it should become good and hot, but not
boil or fume), let cool, and make the mixture alkaline by adding dilute NaOH solution. Shake the test tube and there will be plenty of foam: you have
just created a surfactant.
The surfactant you made is sodium cetyl sulfate, the sodium salt of cetylsulfuric acid, an example for the alkyl sulfate group of surfactants. The
H2SO4 has formed an acidic ester with the cetyl alcohol, and the sodium salt of this ester is a surfactant (the free acid not, though).
We were shown this experiment in school as introduction to the "detergents" unit. I call it "worlds simplest surfactant synthesis".
Cetyl alcohol is available from shops for selfmade cosmetics.
It is used as a component in lotions. You should also definitely be able to get this at the pharmacy- they need it for making special lotions, and you
can tell them you want to do just that.
[Edited on 28-10-2007 by garage chemist]
|
|
|
Mason_Grand_ANNdrews
Hazard to Self
Posts: 63
Registered: 19-1-2006
Location: New Berlin City !!
Member Is Offline
Mood: crabby
|
|
Excuse me guys for my comment, i don`t want rape  the thread. In my opinion is the
synthesis of tetramethylammonium
hydroxide (tetramethylammonium hydroxide pentahydrate)
(CH3)4N(OH) more than a delicate way like the synth. of
(Methanolamin, CH3NH2). In my opinion told the name of the
chemical only somewhat to the existing form of a tetramethyl
salt and the way where it came from.
Why dosen`t exist it in the form of (CH3)NH2 trimethylamin ? I mean the correct way to the salt is the synth. from ammonium
chloride and the substitution of the hydrogen ions within a of
slight coordination of different iones to the nitrogen. My bad
knowledge and some short infos thold that some industrial
methods uses a cartalyst to make such a salt in presence of
lewis-acid or tetrafluoroborates.
Maybe one of the easy possibillityes is when 100 g of anhydrous methanol is heated to the boiling point and ammonium chloride is added until noting
dissloves. The mix is chilled and diluted with around 265 g of anhydrous
dichloromethane or 232 g of diethylether. The mix is dumped to
a very big 2000 ml flask and refluxed for one day below 40 °C.
(Flask is sealed with a glas wool stopper)
When the mix is chlilled some unsoluble crystals of
tetramethylammonium hydroxide should be precipitate in the
layer of CH2Cl2. Maybe someone can test it out, it´s only a little
extract from the theorie what i`ve read about the formation of
such a salt in a gas phase. Might it works better when the
temperature is increased up to the bp of methanol. Yield is
small but i mean it should work.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
Nope, you're not going to break the C-O bond in methanol under those conditions.
You can make the methyl-amines from methanol and ammonia by passing the mixed vapours over heated catalyst. Nickel, copper, Cu-Ni alloys, copper
chromite, and others work, temperature range is 300 to 500 C depending on exact catalyst and other stuff. You get a mixture of the 3 methyl amines,
which one predominates depends on the ratio of MeOH to NH3 and other things.
Note that you a in effect dehydration things : ...NH + MeOH <=> ...NMe + H2O, that C-OH bond is pretty strong. The hot tube route may
actually be doing H-C-OH <=> H2 + C=O, C=O + NH2 <=> C=N + H2O, C=N + H2 <=> H-C-N-H (ignoring the other bonds to C and N) as
well as more ionic reactions.
Going beyond that, the 4th C-N bond of quaternary ammonium compounds is a little tougher to make, and much more difficult to break.
|
|
|
JohnWW
International Hazard
Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
The general method for making quaternary ammonium salts is to react a tertiary amine with a carbonium cation generated from a compound which
relatively easily ionizes, in an electrophilic addition of the carbonium cation to the unused electron pair on the N atom, in a solvent with the
molecules of which the carbocation is much less likely to react and in which the tertiary amine is soluble. Alkyl halides usually have a slight degree
of ionization which can be taken advantage of for this purpose.
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
JohnWW, the methylation of ammonia and methylamines with methyl halides is not an SN1 reaction as you claim. It is just a plain simple SN2 and no
carbocations are ever involved. Alkylation of amines going through SN1 mechanism are extremely rare.
|
|
|
Mason_Grand_ANNdrews
Hazard to Self
Posts: 63
Registered: 19-1-2006
Location: New Berlin City !!
Member Is Offline
Mood: crabby
|
|
In my opinion the synthesis should work with strong reflux.
The conditions of the dc temperature and the reaction
between MeOH an ammonium chloride are not common.
Excuse me, it seems a little mistake in the description of my
issues. 
The bp of MeOH is around 64.7 degree centigrade and some
infos told that the vapors of MeOH and ammonium chloride
gives an small amount of TMAOH. 
I mean a deep chemical knowledge is necessary to make
the material in higher yield. I mean it is works when
100 g of anhydrous methanol is heated to around 64
degrees centigrade, ammonium chloride is added until noting
will dissolves and the mixture is refluxed for one day in a
large flask (> 64,7 degrees centigrade). The mix is tha slight
chilled and stirred into 265 g of anhydrous dichloromethane
or 232 g of diethylether. A small amount of TMAOH should be
precipitate in the solution. I mean the synth. takes some
experiments with the correct temperature. Some by-products
are surely ClCH2OH, Cl2CHOH , NHCH2OH, ClNHCH2OH ,
CH2NH2OH, (CH2)2NHOH and something more but when the
reaction correct work TMAOH should form in the vapors of
the MeOH.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
