Sodium Ethoxide and anhydrous EtOH

A great procedure!

At the first look it sounds quite unbelievable, especially for those, who wasted their sodium metal for this reaction.

BTW: Did someone try this reaction with MeOH instead of EtOH?

- Interesting, but what makes the first quarter contain the water, does it form a seperate layer?
- Yes it does. Salting out is the principle behind this.

- Why are we removing 1/4 of the ethanol solution and not a visible product or anything related to the amount of water in the ethanol?
- To make sure all water is removed. A rule of thumb not more not less, not optimized.

- How much NaOH is dissolved in the liquid contaminating the ethoxide product?
- This I cannot answer, not very much if the ethoxide/alcohol is withdrawn from top and not at the bottom. This is what the patent says at least. I guess the alkoxide salts the NaOH out of the alc. for its higher solubility.

- This is a very unauthadox method
- This a a patented method

As I posted it at the HIVE times ago:
"Patent US2796443 1956 to Dow Chemicals, describes a process for the production of alkali-alkoxides which requires no distillation. I basically works with an excess of hydroxide which saturates the water which can be withdrawn at the bottom, whereas the alcoholic anhydrous alcohol/alkoxide solution is withdrawn at top of a reactor."

The whole thread is interesting I want to say:
Alkoxides

There also a method for removing the water by azeotropic distillation with toluene is described. I believe the method as told by me is easier. And it works. Whereby I am not sure for the azeotropic distillation as salts fuck up almost every azeotrope. But thats an educated guess, not more. Benzene might work and would work for sure better than toluene, when toluene works at all.

- At the first look it sounds quite unbelievable, especially for those, who wasted their sodium metal for this reaction.
- You dont really want me comment on this?

- BTW: Did someone try this reaction with MeOH instead of EtOH?
- Works on MeOH too. No problem.


In short:
Adding excess NaOH to EtOH which contains water salts the water out. Separate and distill, all remaining water will by sure be removed by the alkoxide formed in step one.
Nor so hard at all.

Marvin: The process is so obvious and easy I thought it being ok to post it as rule of thumb. Withdrawing 1/4th works for sure and will give also the beginner a good result. Those who know the art may be able to distinguish the aqueous and the alcoholic layer by eyeballing though...
Just remove the aqueous layer as it is formed, shift the equilibrium this way and enjoy! Thats for pure alkoxides. For anhydrous alc. and alkoxides which maybe a small contamination of hydroxide the method as described first suffices.

Yes sometimes this is not really hard.
And sometimes its much much harder as it sounds I want to add.


[Edited on 9-10-2004 by Organikum]

I have a complaint: Edit your post instead of doubleposting! Hah! Got you there!

Now it's very possible I was wrong there. I haven't heard of any method for making sodiumethoxide this way untill today. I can't for the life of me remember what I said in that thread though. Tzzz, Alzheimer and still so young.

Googling for +Cannizzaro +alkoxide returns no relevant hits for me, so I can't verify the veracity of ethoxide replacing hydroxide in the Cannizzaro reaction; having just reviewed the mech, however, it seems theoretically possible.

Someone ought to try it out, then...

But wouldn't the water generated by the reaction consume the ethoxide as well? (scratches head)

sparky (~_~)

What water? Oh, I should have been talking about methoxides and methyl esters instead of ethoxides and ethyl ester, well anyway:

PhCHO + PhCHO + NaOMe --> PhCOOMe + PhCH2ONa

[Edited on 9-6-2005 by trilobite]

When I wrote my previous post, my eyes were trying to shut themselves out of their own accord. Sorry about that, you're right, if it's just alkoxide and aldehyde in the reaction vessel, there's no water.

sparky (~_~)

alkoxide exchange

Drat!
Mg(OEt)2 isn't very soluble. I might have to start with Mg +MeOH. Add NaOH to get NaOMe and add excess EtOH then distill off MeOH to get NaOEt.

sodium ethoxide//metallic sodium

Yes it is likely that Organikum simply cannot be trusted

However , setting aside the political credibility issue in the interest of science , ........

After all *if* it is a simple solubility driven equilibrium reaction as the patent states , the reaction should proceed to the right according to the greater affinity of the solid hydroxide for water . The hydroxide in excess wins the battle for the water . If this holds true , then the counter current scheme is simply a means of continuous production convenient on an industrial scale , as an efficent method , and keeping the apparatus compact in size . But for a laboratory method , the same reaction should be accomplished simply by long stirring of an excess of what NaOH will be dissolved in
ethanol heated to near its boiling point . Over time the
same equilibrium will be reached . The liquid portions
should separate on standing and the upper layer of
ethoxide in alcohol could be pipetted or decanted ,
or the whole of the liquids decanted from the solids
into a separatory funnel . Perhaps some sort of color indicator could be used to distinguish the phases if needed , but I am going to guess that the ethoxide layer will likely have a slightly yellowish cast and the interface
should be visible .

Dow is a huge chemical company , so it seems unlikely that one of their patents would be total bullshit .

The experiment to examine this is as simple as I have described , and I will get around to it myself unless
someone else beats me to it first .

As for the electrolysis oxidizing the alcohol , perhaps
and that may depend upon the anode material alone ,
or it may require a partitioned cell ....I do not know ,
and I would bet good money that you don't know either .

Until experimental results are found , then my theory , hypothesis , guess or speculation , is as good as yours
and so is Organikums .

Azeotropic removal of water from a non-excess of NaOH in ethanol by using a benzene additive to the mixture to create a ternary system of ethanol-benzene-water , which distills away and from which the water can be separated in a Barrett water trap , leads to a solution of sodium ethoxide in the dried ethanol in the distillation flask . See the patent attached . This is simply another way of shifting the same
reaction equilibrium to the right , correct ?

In another thread someone mentioned having experimented with toluene as an alternative to benzene
described in an even older patent .

Attachment: GB377631 Sodium Ethoxide via Azeotroping.pdf (169kB)
This file has been downloaded 1631 times

We have here Organikum and Rosco sitting side by side
on the trick board over the dunk tank , mercilessly ridiculing the crowd of novice baseball pitchers .....

Todays " two for the price of one special "
Could it be they will stay dry , or is it bath time
for the reaction dynamic duo ?

Okay all you physical chemistry apprentices
it's three balls for a dollar , so step right up
and take your best shot

So what about Rosco's modification ?

The patent you mentioned is attached and bears out what I have been saying .
Thank You

Just to be clear , this reaction should proceed towards the right without any counter current scheme
at all , simply by having * solid * NaOH always present
in excess in the reaction mixture maintained for awhile near the bp of the ethanol .

When the hot mixture reaches equilibrium , the alcohol phase will contain predominately the ethoxide as its dissolved sodium compound .

[Edited on 3-9-2006 by Rosco Bodine]

Attachment: US1978647 Acetone Precipitation of Sodium Ethoxide.pdf (201kB)
This file has been downloaded 1645 times

"After all *if* it is a simple solubility driven equilibrium reaction as the patent states"

I am guessing that since you did not substantiate this in either of the two posts following my request that it is simply untrue.

"The thinner film of aqueous hydroxide solution on the hydroxide pellets at the top of the column has no greater dehydrating property than the...."

I would agree that I also do not consider mechanical reasons to be worth arguing for the performance of the column, or kinetic ones. If reaction rate is the issue a home chemist can always wait longer.

I would state that such possible effects as K2O produced by heating the KOH isn't worth thinking about, to all real intents and purposes it doesn't happen.

I would insist that KOH and NaOH as powders have surface absorbtion properties that are very strong, but I concede that these effects are probably not important on the molar scales in the context of this thread and would not by themselves prove my argument.

"their desiccant property is due to a surface reaction of deliquescence . The affinity for water is to form a saturated solution , which has a uniform vapor pressure "

You are stating that the deliquescence is the basis of the dehydrating power, and that while solid KOH (for example) is in contact with the resulting saturated solution a change in the overhead vapour pressure of water would cause more or less KOH to dissolve until equilibrium is again reached. Since the composition of the solid, and that of the solution don't change only their amounts do, the vapour pressure of water must be constant while both exist. I can't fault the logic. The bad news is that the chemistry is wrong. At RTP solid anhydrous KOH will absorb water, neglecting surface kinetic effects it will continue to do so until it is entirely converted into the monohydrate, which is solid. KOH.H2O will continue to absorb water with slightly less enthusiasm until it is converted entirely to the dihydrate which is...... solid. KOH.2H2O will continue to absorb water with slightly less enthusiasm still until entirely converted to KOH.4H2O which is a liquid. I say liquid and not solution, because it really is a molten hydrated salt, if you cool it you get KOH.4H2O as crystals. The behavior of the solution then gets more complicated, but is outside the required scope for this thread and beyond any reference material in my home library anyway. Sodium, rubidium and Caesium hydroxide have at least 1 solid hydrate each at RTP in addition to the solid 'anhydrous' forms. I use the term with care as in very old textbooks the anhydrous XOH are themselves considered to be hydrates of X2O, so to be clear an XOH and at least one XOH.nH2O both solid at RTP. In the case of sodium there are in total about a half dozen individually distinct hydrates mostly liquid at RTP. Returning to KOH and the patent, at the temperature of the column the anhydrous form and monohydrated forms are solid, the dihydrate and tetrahydrate are miscible liquids, being a changing mixture the dehydrating power is continuously variable depending on its composition. So depending on the point in the column you are looking at you have anhydrous/monohydrate desiccant or monohydrate (solid)/dihydrate (liquid eventually, there is no requirement for a sharp change in melting point) or a liquid consisting of varied proportions of the dihydrate and the tetrahydrate, and with a desiccating power that depends on the ratio in the active phase.

"You are basically declaring that the hydroxide itself has different levels of hydration according to its height in the column , wetter at the bottom and drier at the top "

Yes, that is exactly what I'm stating.


Nicodem,

There is no one here that is challenging the claims in the patent, which renders most of your post a cheerleading chant for a nonexistent cause. The question in the thread is on exactly how the process in the patent works, and if the modification proposed at the top of this thread is equivalent. You do also provide a number of important facts.

"Conclusion: Ethanolic solution of NaOH contain a lot of ethoxide ions in relation with the hydroxide ions."

This is certainly true, and a dilute solution of sodium hydroxide in absolute ethanol can be nearly 100% ethoxide. Ethoxide is the stronger base though, and simply adding an acid, ethanol, to a base, sodium hydroxide, cannot result in a solution that is more strongly basic unless something is doing work. These reactions must be pushed up hill. Of course required purity and solvent is strongly dependant on what the ethoxide is going to be used for. A second point, is that with hydroxide and ethoxide (and water) in the same mix, if the hydroxide is kinetically better than the ethoxide, even a small amount may do a disproportionate amount of damage, as the hydroxide is used up more will be created as ethoxide is destroyed by water to maintain the equilibrium. While your conclusion can well be true, on its own it doesn't mean anything.

"The prejudice that sodium ethoxyde and similar alkoxydes are exceedingly difficult to prepare by a hobby chemist ...."
"Conclusion: Producing alkoxydes higher than methoxyde, without resorting to sodium or potassium metal, is no big deal."

Your conclusion does not follow by any logical or chemical means. This is just rhetoric.

"The H2O in NaOH/KOH alcoholic solutions is not mysteriously bound, only its concentration is bound... "

This may be a useful conclusion, had someone actually assumed this. No one has.

"Conclusion: Organikum’s modification can only be considered faulty as a method of preparing truly and absolutely dry ethanol, but as a method of NaOEt production there is no reason to believe it does not work"

I find it interesting that Organikum's method as an absolute alcohol process is flawed, this passed me by completely, much thanks for bringing the Vogel information to our attention. The second part to your conclusion does not follow logically unless two conditions are met, firstly that the distillation is done slowly with a fractionating column, when azeotropic distillation would dehydrate the remaining hydroxide/ethoxide mixture, a simple or rapid distillation could well fail to further conversion. Secondly it relies on the degree of dehydration of the alcohol used to exceed the water produced by the conversion of hydroxide to ethoxide. Otherwise alcohol will be exhausted as azeotrope before all the hydroxide is gone. Since the alcohol Organikum is using is wet, and no directions on distilling are given neither of these conditions are automatically met and there is considerable question as to how successful it is as a complete method. With modifications though, it could well be made to work with more complicated means and equipment. If the amount of dehydration of the wet alcohol below azeotropic by the sodium hydroxide removed exceeds the amount required to dehydrate the sodium hydroxide that remains dissolved in it, then following fractionation substantial conversion to ethoxide should occur. There are a lot of variables though and the conditions are a long way from being automatically satisfied.

In other words there is every reason to believe it does not simply work as stated.

In addition to previously discussed trinary azeotropic methods, sodium alkoxides can be produced using magnesium metal as detailed elsewhere and in Fieser as a method for making very dry alcohol (Magnesium hydroxide being insoluble in the mixture, the ethanol is decanted and distilled off from remaining magnesium ethoxide).

The acetone method is new to me, and I find it suspect. Not because the production of sodium ethoxide by precipitation seems so unusual, but because acetone is well known for being incompatible with strong bases.



Rosco,

"At 70C , the deliquescence is augmented greatly over what it is at room temperature , in contact with solution water "

Having shown the mechanism of dehydration to be different to that assumed this no longer makes sense either. While hydroxide will be more soluble in the water the real question is the vapour pressure over a hydrates salt, which generally increases somewhat with increasing temperature. Heat will certainly reach equilibrium faster, but it may turn out to be better to let the system cool after and crystalise more of the hydroxide as a hydrate.

"Just to be clear , this reaction should proceed towards the right without any counter current scheme at all , simply by having * solid * NaOH always present in excess in the reaction mixture maintained for awhile near the bp of the ethanol "

There are no claims in the patent regarding sodium ethoxide, so just the use of sodium hydroxide and ethanol in the full process may produce unacceptable results and stretches the patent as evidence beyond its breaking point. At best had the yield been higher they would have listed this instead. At worst it does nothing useful at all. This is why I've concentrated my examples on KOH, which the patent can be considered fair evidence for success in the column.

I think it is now clear why a counter current is so important, as put forward and explained by not_important and myself.

Modifying the method may be feasible, much larger excess of hydroxide, fractional distillation of the remaining ethanol, but this is something that would have to be done experimentally. Its not about the potential of a method to do well by our limited understanding of the chemistry, it's about evidence and reliability.

But that is exactly what I wanted it to be.
I believe there are still a bunch of hobby chemists who question the patent and there are still many others who don’t even realize that producing NaOEt from NaOH is possible. I did not want to intrude in the “Marvin vs. Rosco debate” about the mechanism behind the NaOEt formation by that process, since it is obvious to me that it is a dehydration process where the ethoxyde/hydroxide ratio exponentially raises with the distance up the column. This is already evident from the equilibrium constant equation and the partition theory of extractions. Furthermore, since the increase of the ratio is exponential with an already good starting point, I would say that one or two Organikum’s partitioning of H2O among conc. NaOH(aq) and conc. NaOH/NaOEt(EtOH) gives a relatively satisfactory resulting purity for the NaOEt produced after distilling off the solvent. Its purity should be enough for most uses (meaning >90%).
As for the other details of the current debate, I’m not really interested enough nor am I competent enough, but I see it mostly as another annoyance that may deter experimenters to use this method or its variants. If you two are working together to find out an optimization then that is just great, but unfortunately it does not look like this at all.

The patent states that the operative requirement for
the amount of excess alkali hydroxide , is a minimum of
0.1 mole to a maximum of 0.4 mole beyond the theoretical
amount required for the alkali which will be bound chemically in the ethoxide . Having less than 10% molar
excess of alkali hydroxide , the equilibrium for the reaction
will drift back towards the left . This small amount of
10% excess beyond the theoretical requirement is very pertinent to my " making the leap " in proposing that
this reaction shouldn't require any column at all , and
should proceed in a similar way as a batch process
although the minimum excess of theory might be tripled
without a column , to keep the time of reaction reasonably short .

Concerning the hydrates of alkali hydroxides which you have mentioned , I had already thought about the possibility of a series of such possible hydrates which are formed from evaporation from hot melts being concentrated , where in *liquid* form there well may
be a stepwise dehydration marking distinct hydrates ,
which have identifiable melting/solidification points as
distinct hydrates . But those distinct stages of hydration
would only come into consideration for the entire mass in
the molten condition , and have no bearing for the dessicant properties of the material after it has cooled and solidified . After solidification , the absorptive properties of the *solid* are virtually gone with regards to any practical reaction rates and the solid does not
behave the same as would say for example a liquid
hydrate of sulfuric acid , which as a liquid is free to
seek different levels of hydration for the mass ,
as if swelling like a sponge . When you have the
hydration status of a melt * locked * in place upon
solidification and cooling which effectively seals the
interior of the solid from exposure to external moisture ,
then its dessicant properties is not absorptive en masse
but is shifted by the physical limitation of the solid to
become a surface reaction manifested by deliquesence ,
forming an aqueous solution as a film wetting the surface
of a structure beneath which does not change , but
is like an ice cube sitting in liquid water so cold that
the ice cube does not melt further nor further freeze
until the properties of the liquid in contact is changed .

When handling solid prilled alkali hydroxides , you may notice that when the " dry " solid granular material
is exposed to the humidity of the air , during weighing operations for example , it does not gradually swell in volume as a still solid material passing through stages of higher and higher yet still solid hydrates and then sudddenly liquify en masse . But what does happen is an almost instant formation of a film of liquid on the surface of the prills which makes them adhere to each other .

Even if it is aknowledged that different stages of dehydration do occur in a melt which is being concentrated at higher and higher temperatures of fusion , this does not necessarily mean that the
reverse sequence of rehydration occurs in like stages
for the cooled and solidified melt exposed to moisture
upon its surface . It is not the same case or mechanism
as would be for a porous silica gel which physically
absorbs water . Nor is it the same case as for a
porous material like drierite , or for a liquid dessicant
like sulfuric acid . A deliquescent material operates
according to a distinctly different process .

Many of the deliquescent nitrates behave exactly the same way , calcium nitrate and magnesium nitrate are
two which come to mind .

Anyway , for the 10% molar excess to be the lower limit
for driving this reaction *completely * to the right , in a vertical columnar reaction zone having a 24:1 height to diameter ratio in ( inches ) for the reactant is a very mild
contrast of conditions , in my opinion , over what would be the effect in a " one pot " batch reaction , compensating for any absence of the reaction zone gradient which may be the benefit of the column simply by using a greater excess of solid alkali hydroxide in the one pot process .

As an integral part of my contemplated one pot variation , what I had fully intended was to add a fair amount of toluene to the ethanol solution over dissolving and excess undissolved solid hydroxide , *during* the boil , lettting the added effect of the azeotropic
dehydration augment the dessicant property of the alkali hydroxide , and shorten the time required as well as
produce an even more complete conversion .
Rosco's good old country recipe for sodium ethoxide
would marry the salting out effect of Organikums column reactor with the concurrent azeotropic removal of water applied as the " kicker " to eliminate the entire issue of debate concerning the column .

Anybody got a ternary mixture data chart handy for
toluene /ethanol/ water ?

Basically all you would need to do is place your weighed
quantity of NaOH prills and a stirbar into a stoppered flask with the measured amount of ethanol , bring it
up to a boil until you have a saturated solution over
the excess of undissolved solid NaOH . Allow the mixture to cool down a bit and add your toluene . Return the mixture to a boil and let it sit there boiling away like a whistling teakettle . There would probably be so little
of this added azeotropic removal of water needed that
on a lab scale it would be sacrificial solvent loss here ,
and little point in using a reflux condenser , water trap
and solvent return as would be used for economy with
large batches .

There could be worked out some optimum proportions
which would make this straightforward , and a standard
method .

The only point of uncertainty about this proposed method
is whether or not separation of the phases might have to be done before adding the toluene for the Azeotroping , and
if any fresh sodium hydroxide being added with the toluene
might also be beneficial to the yield from that point .


CRC lists the ternary azeotrope : bp 74.4
ethanol 37
toluene 51
water 12

The boiling point with decreasing water
should gradually rise towards the binary azeotrope: bp76.7
ethanol 68
toluene 32

Absent any toluene ,
The ethanol water binary azeotrope : bp 78.2
ethanol 95.6
water 4.4

And for pure ethanol the bp is 78.5 C .

It may be practical to follow the course of the reaction
simply by watching a thermometer observing for the cessation of gradual elevation in boiling point and the appearance of precipitated solid sodium ethoxide as the solvent is boiled away . At this point the product
is available as its saturated solution in the supernatant ethanol .

[Edited on 4-9-2006 by Rosco Bodine]

I've just tried to make aluminium isopropylate or Al isopropoxide and it works quite nice without CCl4 or CHCl3, only with HgCl2 and some iodine. I cooked it originally just for fun to get the reagent for the Meerwein-Ponndorf reaction, but it works that nice that it would be probalbly also possible to get sodium ethoxide from it, if you exchange isopropanol by ehanol. Like:

Al(OEt)3 + NaOH ==> NaOEt + Al(OH)3

AlOH3 is insolule, so the reaction is quantitive

For Al(OIpr)3:
I took Al foil and Al turnings put it in a 2l RBF and added 1,3l isopropanol and a few grams of I2. I heated it, but nothing happened, so I added a bit NaOH , I thought it could complex the oxide layer, but nothing happened too, so I took my last bit of HgCl2, made from a small mercury switch, it was something like 0,25-0,5g and added this and the reaction worked quite vigorous. I could place my hand on the top end of the condensor and felt the pressure of the hydrogen evolved.
The isopropanol was technical, 95% or so.

Reference Information

That first article kicks shit out of the Nature letter.

Thanks Solo

Perhaps, given the importance of Sauron to this forum, it is time to shift this stuff over to WD? I mean, I ain't allowed to irritate the fuck and much of my contribution irritates it. QED, the majority of my contributions are not welcome on this site.

PS This fits in well with the suggestion made elsewhere too, don't it?

[Edited on 24-2-2008 by LSD25]

Any water will react with ethoxide producing more hydroxide.
It is impossible for it to contain water.

Quote:

Originally posted by The_Davster Any water will react with ethoxide producing more hydroxide. It is impossible for it to contain water.

Siddy, try reading the whole thread. I'm sure you will better understand that you are dealing with equilibriums. The ethanolic phase can, and surely does, contain some water (as long as there is some hydroxide anions, there is H₂O as well since OH^- + EtOH <=> H₂O + EtO^-. Hence, if you want a very pure ethoxide ethanolic solution, you need a continuous equilibrium shifting (like is for example done in the title patent where a counterflow method is used). But for most applications, a single or double equilibration will give you sufficiently pure ethanolic sodium ethoxide solution (it all depends on what you'll be using it for).
If you are planning to prepare solid NaOEt, then you can remove traces of water by adding some toluene, distill off to half volume and continue by drying under vacuum (always keep in mind its pyrophoric properties!).

Use sodium oxide

Quote: Originally posted by no1uno

... pass in dried ethanol (passed through H2SO4, then over CaO) ...

ethylate

This experiment has been based on the patent (US2796443) mentioned in this post. Since I need to acquire some sodium ethoxide, I decided to give this method a chance, because I would very much like to avoid ordering pure Na, which is quite expensive where I live.

Following the ROH + MOH <-> ROM + HOH equation, and having in mind that the patent states that a surplus of 0.1 to 0.4 (in my case ~0.12) moles of NaOH should be added, in addition to the stoichiometric amount, I added about 250 ml of 96% ethanol (4.11 moles) to 200 grams of NaOH (5.00 moles).

When the ethanol was added to the sodium hydroxide, a quite amount of heat was evolved relatively fast. A moment later, the cylindrical beaker was placed in a hot water bath in order to achieve and mantain the temperature around 70°C. When the solution reached the mentioned temperature, I left the reaction to carry on for half an hour.


(click for a larger pic)

The result can be seen on the image above. As stated in the patent, there is indeed a dense fraction that can be seen reaching a bit above the layer of NaOH (picture to the right). This should be composed mainly of water and sodium hydroxide. The solution above the mantioned fraction should contain mostly ethanol and sodium ethoxide.

I didn't expect these two fractions to be that clearly separated, but it certainly did help in the separation of the two, which was done by slowly extracting the alkoxide layer with a pipette, soon after the picture was taken.

The obtained solution has just a slight yellowish color, although you can see that the upper layer of the NaOH is clearly yellow colored, while at the bottom, the NaOH has a clean white color which is also conforming to the patent which claims that the alkoxide rises upwards during the process.

I'm not sure what would be the best way to extract the ethoxide from the solution. I was thinking about distilling the solution until the ethoxide starts to crystallize and then cool the solution to the lowest temperature that I can achieve over a longer period of time (~ -26°C ), in order to lower its solubility. Then the ethoxide would be separated by simple filtration?

[Edited on 5-7-2010 by Sciocrat]

Quote: Originally posted by flavaflav

This EtONa is heavily contaminated with NaOH which can only be removed by azeotropic distillation pushing the equilibrium in favor of the ethoxide or by using molecular sieves to do the same thing.

I made today sodium methoxide. Pure Na metal (25 g) slowly dissolved in 350 - 400 ml methanol , to even 5% water (ethanol 95%) catch a fire is almost impossible (almost ). The first 3-4 portion of sodium didn't heat a lot of whole mixture but still i put baker in cold water (cooled very good) , at about 15 g sodium and more the whole mixture turned a slightly yellow and at the end just more yellowish colour , liquid had much more density (look like sirup). I put the baker on heating mantle and start to boil off solvent , after evaporate about 100 ml the white mass start to floating on top of surface liquid, after evaporating the whole solution there was in a baker hard rock mass, i quick turn these "rocks" into dust, and i got about 50 g of pure, anhydrous, white sodium methoxide. Very nice synthesis but some kind of time consuming.

PS. "dust" mask and googles and of course gloves in key safety gear in this synthesis , dyust of Ch3ONa is very unpleasant

[Edited on 28-6-2011 by mario840]

Here's an idea from left-field

Add some aluminium -

I'm thinking that the NaOH will react with any oxide/hydroxide to give the sodium aluminate IN the presence of water, while any water will react with any clean aluminium to give the aluminium hydroxide, while the ethanol would react with clean aluminium to give the aluminium hydroxide via metathesis of the formed alkoxide.

Just a thought, there's presumably any number of problems with it, just thinking and typing while I'm looking up something else in another tab

Quote: Originally posted by madcedar

There is a valuable post by Nicodem near the start of this very thread. Here is the link. [Edited on 7-12-2013 by madcedar]

Quote: Originally posted by aliced25

Here's an idea from left-field Add some aluminium - I'm thinking that the NaOH will react with any oxide/hydroxide to give the sodium aluminate IN the presence of water, while any water will react with any clean aluminium to give the aluminium hydroxide, while the ethanol would react with clean aluminium to give the aluminium hydroxide via metathesis of the formed alkoxide. Just a thought, there's presumably any number of problems with it, just thinking and typing while I'm looking up something else in another tab

Quote: Originally posted by madcedar

It turns out the sodium ethoxide is really easy to make with nothing more than sodium hydroxide, ethanol and acetone.

Quote: Originally posted by AJKOER

Thanks Blogfast for the review. I have corrected the hydrolysis reaction, but I believe my chain is still valid assuming [...]

Quote: Originally posted by Sedit

I know its derailed but shouldn't Aluminum be able to replace Phosphorus in the reduction of Benzylic alcohols using HI as long as there is enough Al present?

I tried to make sodium ethoxide by reaction of anhydrous ethanol with Sodium hydroxide.

I distilled mixture for bring out the Ethanol that make azetrope with water and added more anhydrous ethanol for pushing this reaction to right side.

NaOH + EtOH <==>NaOEt + H₂O

I used 40gr(1 mole) NaOH and 92gr EtOH(2mole) also added 400 cc excess Ethanol for making azetrope with water but it seems no Ethoxide formed.

I checked density of distilled ethanol and that was 0.793(near dry ethanol)and also i added calcium oxide to it but temp didnt increase.
somebody has experience on this reaction?



Setup


Ethanol + Sodium hydroxide


Color of mixture changed after some heating


Small solid start to float on mixture


more solid


after adding all Ethanol


when all of ethanol distilled



[Edited on 13-1-2014 by Waffles SS]

Quote: Originally posted by Waffles SS

I distilled mixture for bring out the Ethanol that make azetrope with water and added more anhydrous ethanol for pushing this reaction to right side.

Quote: Originally posted by Nicodem

Quote: Originally posted by Waffles SS   I distilled mixture for bring out the Ethanol that make azetrope with water and added more anhydrous ethanol for pushing this reaction to right side. The difference of bp between the azeotrope and pure ethanol is less than half Kelvin. There is no way you could quantitatively remove water with a distillation employing such an insignificant difference, not even if you used a distillation column. You would need to add toluene to make a ternary azeotrope with some significant bp difference and still you would need to apply a distillation column.

Quote: Originally posted by blogfast25

Waffles: Have you tried the procedure that uses acetone as an anti-solvent to precipitate the NaOEt? See top of this page for patent and links. That appears to work well for short chain alkoxides.

Quote: Originally posted by clearly_not_atara

When I discovered this thread, I, like everyone else, thought it was a huge breakthrough in the preparation of NaOEt. After all, NaOH is much easier to obtain and cheaper than Na metal. However, the method has not been successfully applied very often, and the use of Na is still preferred. I think this is all related to the difficulty of working with anhydrous NaOH. The dry powder is very hygroscopic and easily dispersed; it will burn your eyes and skin; and it must be dried at red heat. Anhydrous pellet NaOH, as used in the patent, is virtually impossible to prepare without specialized equipment. Therefore, it is desirable to replicate the method without using anhydrous NaOH. I was inspired by the reaction: Ca(OH)2 + Na2CO3 >> CaCO3 + 2 NaOH Unlike NaOH, Ca(OH)2 is not hygroscopic and is much less caustic. Na2CO3 is still very hygroscopic, but it can be dried at lower temperatures and does not saponify human skin. In order to prevent caking, I suggest the following protocol: A suspension of one equivalent powdered Ca(OH)2 in freshly dried (eg MgSO4) ethanol is mixed with a suspension of 1.5 equivalents anhydrous Na2CO3 in dried ethanol and stirred for several hours in a sealed jar or under nitrogen (NaOEt reacts with O2/CO2), filtered, and the filtrate is treated with acetone to yield, hopefully, a precipitate of NaOEt.

Quote: Originally posted by Organikum

A sep-funnel or anything else with an outlet (faucet) at the bottom is filled to 1/3rd with NaOH pellets and filled full with EtOH of 92% or of higher concentration (preferred). This sits for at least half an hour and then about 1/4th of the liquid at the bottom is withdraw very slowly. Then the rest is withdraw. This rest consists of EtOH which contains sodium ethoxide. Distilled to yield anhydrous EtOH, sodium ethoxide is left back which can be used to dry more EtOH so desired. If the alcohol is pre-dried with anhydrous CuSO4 which was dehydrated at 300°C+ much less NaOH is needed. This pre-drying takes time though, the longer the better in special if no stirring is applied. If the ethoxide is whats desired the alcohol should be left in the vessel for longer time, if bigger amounts are wanted it is favorable to withdraw alcohol/ethoxide from top and water/NaOH/alc from bottom and to refill alcohol. This is an almost continous process then. Tried and true.

Quote: Originally posted by Fyndium

I used some NaOH to distill my wiper fluid ethanol, which was +80C to start with, and it appeared to me that it came over pretty much anhydrous. Apparently, NaOH/Ethoxide is able to hold a lot of water behind. Supposedly, pre-drying the ethanol with MgSO4 would reduce the need.

Does distilling ethanol with NaOH damage boro glassware?
I need some anhydrous ethanol from ethanol contaminated with some water and ethyl acetate, thinking of using NaOH to get rid of the latter two, but I dun want to damage my precious glassware

Cheers.

Quote: Originally posted by artemov

Does distilling ethanol with NaOH damage boro glassware? I need some anhydrous ethanol from ethanol contaminated with some water and ethyl acetate, thinking of using NaOH to get rid of the latter two, but I dun want to damage my precious glassware

I have distilled ethanol many times with NaOH and never had etched glassware. I have used silicone oil and CaCl2 baths to heat them, though - direct heating methods can cause hotspots which will make NaOH eat glass at the end of the distillation, and when liquid is splashed to the walls. With baths, maximum surface temperature can never exceed the temp of the bath, which is around 100-120C with CaCl2 and 130-150C with oil, due to lower thermal conductivity.

I got a frozen joint though, which caused me a loss of one 3n 1L rbf and a stillhead. Thou rest in peace in the graveyard of experimentalism and amateur chemistry.

But, to the topic. I couldn't wait for my lab and did some rudimentary tests with my own boka-fractionated, polished and diluted 40ABV vodka and NaOH.

I first added a small amount of vodka, and added NaOH pellets and stirred, until separate layers were formed.



Then I added more, between 200-250mL, and added more NaOH and stirred, and the liquid heated up a lot, but not too much to handle the funnel. I kept adding NaOH little by little, until layers were separated. They formed bubbles and the boundary closed in just as in any biphasic extraction. The activated carbon residue used to polish the distillate can be clearly seen at the boundary.



The extracted upper layer was at first attempted to drain into a tube for ABV meter, but it had a pinhole, which caused a little leak. Actual measuring cylinder was dug through the rubble, and the ABV measurement and volumetric measurement were conducted. The ABV reported pretty much exactly 0ABV, but I hardly believe the alcohol layer would have been the bottom layer, as the upper layer had a very burning alcoholic odor, but the ABV meter is very sensitive and the most likely explanation is dissolved NaOH, ethoxide and other stuff. The total collected volume was 86.5mL as seen, which checks in the ballpark with the input alcohol, at 40ABV by rough calculation and dilution.

The amount of NaOH required is a lot, but not hefty, and obviously as this was 40ABV, the required amount would be inherently larger than when separating azeotropic product.

It should be distilled and remeasured to see if the resulting product is closer to anhydrous ethanol, but at least the very clear layer separation caught my curiosity if ethanol can be salted out from water with NaOH to make actual close-anhydrous ethanol.

Btw, the OP's funnel concept works for the part that it does form a layer close to the edge of the NaOH pellet mass - but the NaOH will completely clog the funnel and form a cone-shaped conglomerate that is very hard to break down and will prevent draining any liquid, even when poked with piano wire from the drainhead. Instead, just adding ethanol to funnel and adding NaOH pellets and shaking until layer separation occurs could be a more viable option. I have currently a batch of azeo EtOH stirring over MgSO4/CaSO4, and I'll probably strip a sample to see if any desiccation has been occured, and if not, I will do a full-scale treat on the batch and see what the resulting product will be. It is likely I'll do it anyway, because I'm running out of ethanol and simply treating the wiper fluid directly with mass of NaOH will both destroy MEK, detergents and additives and keep the residual water, so pretty decent ethanol should be able to be stripped directly off it.

For the record, I have stripped several batches of ethanol from this wiper fluid product. It consists of azeotropic ethanol, denaturants, detergents and additives to enhance the welfare of automobiles, aka crap that NaOH eats for breakfast. I double distilled this stuff, first directly and then with NaOH, although I only used 4% per weight mostly to kill MEK, I remember getting readings over 100ABV with the warm condensate, so apparently most of the water was also left behind. Using more, up to 10% per weight could be even more efficient, but in the long run it would be nice to find the spot at when the returns do not increase anymore and the rest is wasted as ethoxide.

[Edited on 20-3-2021 by Fyndium]

Quote: Originally posted by Texium (zts16)

It's harmless, but it certainly isn't aesthetically pleasing

It's harmless right? I only have 3 rbfs, so I use them for everything, including boiling and concentrating sulfuric acid

Quote: Originally posted by Fyndium

Btw, the OP's funnel concept works for the part that it does form a layer close to the edge of the NaOH pellet mass - but the NaOH will completely clog the funnel and form a cone-shaped conglomerate that is very hard to break down and will prevent draining any liquid, even when poked with piano wire from the drainhead. Instead, just adding ethanol to funnel and adding NaOH pellets and shaking until layer separation occurs could be a more viable option. [Edited on 20-3-2021 by Fyndium]