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cyberzed
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[*] posted on 5-2-2007 at 08:52
Separation of Acetone and Nitroethane


One found a otc product supposed to contain a mixture of 2 liquids, 50/50 v/v Acentone and Nitroethane.
Out of curiosity one of my collegues has tried to separate those two liquids with a simple distillation setup at 760 mmHg, the distillation flas was loaded with 100 ml of the mixture.
A hotplate and an oil bath was used to heat the distillation flask to 80 degrees whereby the temp of the distilate was 57° (acetone), the flask was distilled to complete dryness.
The temperature of the distillate was 57° during almost the entire distillation process, only at the last 15 ml there was a rising temp trend to 62°.

If distilling such a mixture, should the temp not be 57° and afterwards rise to 114°?
Are there other separation techniques to separate such a mixture?
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[*] posted on 5-2-2007 at 10:36


Just some advice.

1. Fractionate. In order to get a clean seperation by simple distillation you need more difference between the bp's than <60 degrees.

Does nitroethane form an axeotrope with acetone? If so then that would explain why you never got anywhere near the bp of nitroethane. If there's an azeotrope you will not seperate the components by distillation, unless maybe if you distill at high vacuum.

2. Read up on safety with nitroalkanes. Nitroethane is an oxidizer, acetone is flammable. Learn before you burn.

3. Distilling to dryness is very likely not a good idea.

4. Consider stripping off the acetone under reduced pressure which you can do with a water bath at a very low temperature (30-40 C) and a low cost water aspirator pump.

5. A rotary eva[orator would be ideal.

6. Consider a different seperation technique. You might derivatize the acetone to a solid, and filter off the precipitate from the nitroethane.

What is the OTC product? I am pretty sure many of us would like an OTC source of nitroethane.

[Edited on 5-2-2007 by Sauron]
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[*] posted on 5-2-2007 at 11:09


Hi sauron, thanks for the reply ....

So, i have heard that vacuum franctional distillation of such a mixture would indeed be the preferred route over a simple distillation, but my collegue doesnt have a fractionating column nor does he has a vacuum pump, so there goes that route.

I have been searching azeotrope databases online to see if nitroethane possible would form an azeotrope with acetone, but i can't find any azeotrope details for those two compounds, my thought was that the acetone would come over at 57° and then a rise to 114° would be noticable ... this offcourse in the case that there isn't an azeotrope involved.

I can give you the source of the product but it would be unwise to put it on the board here, actually i have sourced several products, i could give them to you by u2u but i don't know this is allowed here, maybe the site admins can give some comments on this one ....

You mention the possibility that it would be able to derivatize the acetone to a solid, could u explain in more detail how you would perform such a reaction ?
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[*] posted on 5-2-2007 at 11:33


The most likely candidate for an OTC product containing nitroethane and acetone is a nail polish remover. Actually, there are some that are 100% nitroethane and others 100% acetone.

But, in a simple distillation at ordinary pressure you should have seen a start at 57 C then a slow rise to 114 C.

In a fractionation you would see a flat 57 C then a sharp rise to 114 C. That's assuming a good well lagged column properly equilibrated, a decent reflux ration etc etc. If you rush things or flood the column you won't get a good seperation.

Now, since you went to dryness and never saw a vapor temp out of the 60s then very clearly you do not have any nitroethane in there.

As far as I can determine there is no acetone binary azeotrope with nitroethane.

Acetone forms solid derivatives with lots of things but the most available and lowest cost is sodium bisulfite. Read Vogel p 340-342 for procedure. BUT first determine if nitroethane is compatible with this reagent.

I am sure there are several gentlemen on the forum who like to make styrenes with nitroethane who can advise you better than I can.

However, if there's no nitroethane in there, what is the point?

[Edited on 5-2-2007 by Sauron]
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[*] posted on 5-2-2007 at 12:26


Sauron, have to hand it to you, that was fast searching, it is indeed an artificial nail remover supposed to contain 50% acetone and 50% nitroethane to loosen up artificial acryl finger nails.

Since we did not see a temp rise when distilling the product we can assume that most likely indeed there is no nitroethane in the mixture, but only pure acetone with maybe small amounts of unknown impurities.

According to the msds from artificial fingernail products one can tell that it indeed should contain that mixture, even the label on the product specifies this, i guess the nitroethane from those products most likely has been removed by some man in de middle sales organisations, thats a negative ...

Are you sure acetone forms a bisulfite addition product, i also thought this was only suitable for aldehydes?
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[*] posted on 5-2-2007 at 12:49


Quote:
"Are you sure acetone forms a bisulfite addition product, i also thought this was only suitable for aldehydes?"


Yes, I just reread Vogel, there are only a few ketones that do not form bifulfite addition products. Acetone isn't one of those exceptions.

There used to be a brand called REMOVE that was 100% nitroethane. It was for removing nail polish I think rather than softening fake nail adhesive. There was a child poisoning accident in the mid 90s, and maybe they changed formulations after that.

But you might want to go shopping for this sort of product and read the labels.

Or ask our styrene making colleagues here if they know of any such brands.

Vogel also contains procedure for making nitroethane which seems pretty easy. But I've never tried.
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[*] posted on 5-2-2007 at 13:33


Most methyl ketones for bisulfite addition products, the larger the chains the less readily the addition product forms. It's not a step function, diethyl ketone forms an addition product too, but under normal conditions only a few percent of the ketone ends up as addition product.

When reacted with 1 equivalent of bisulfite, after 1 hour the resulting amount of addition product was

acetaldehyde 88,7%
generic RCHO 70 to 90 %
acetone 56,2%
MEK 36,4%
MPK 23,4%
MiPrK 12,3%
MtBK 5,6%
DEK 2%
acetophenone 1%
cyclohexanone 35%

Note the effect of the ring exposing the carbonyl, increasing reactivity. Also note that with 1:1 ratios none of the compounds go to 100% reaction, which is why an excess of bisulfite is always used.



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[*] posted on 5-2-2007 at 13:45


I did not know that acetone also formed a bisulfite addition product, which book from vogel did u get this out?

I have been searching well over a year now to a viable route to nitroethane, and still did not found one, there are indeed a few sources which are well documented i think on all forums like adhesive removers, fingernail products, acrylic solvents and so on.....

One could indeed synth it but the only synths which are safely in reach are badly documented and require hard to procure reagents, in my opinion the only synth which is doable seems the reaction with sodium nitrite and sodium ethyl sulfate under KCO3 catalyst.

You say you have a easy synth in the volgel, if i don't have it already i would be interested to hear from this one ... if it is already on the nitroethane compilation list then don't bother, then i already have it.

As far for those styrene make collegues, if one would like to hand me a source i would surely listen to this information...
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[*] posted on 5-2-2007 at 14:04


Thanks, not_important for this info ....

So i guess separating such a mixture by forming a bisulfite addition product with the dimethyl ketone is not an option since there will always be something left in the mixture.

Another pathway i was thinking of separating this mixture of liquids was by the solubility in dH2O:

acetone solubility: Miscible in all proportions in water
Nitroethane solubility: 4.50 g/100 mL

Wouldnt the acetone mix up with the water, while that one pushes the nitroethane out of the mixture wherafter two layers would be visible?
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[*] posted on 5-2-2007 at 14:12


On the topic of the preparation of nitroalkanes, I had a look at the pages in Vogel Sauron mentioned. In general, the nitroalkanes can be made by heating an aqueous solution of alpha-monochlorocarboxylate (or bromo-, as suggested in the Rhodium archives) together with NaNO2. For nitroethane, the synthesis would require the salt of alpha-chloropropionic acid.
Mephisto found a preparation, in which alanine is reacted with NaNO2/HCl to give the required acid:
https://sciencemadness.org/talk/viewthread.php?tid=3961#pid4...

Albeit low yielding (32%), alanine shouldn't be hard to come by. The problem is as always NaNO2, but this is also necessary in the nitroalkane preparation from NaEtSO4.

I am sure this has been mentioned somewhere before, but I don't recall reading about it.

Edit: Ok, most of it seems to be in the Rhodium. The route from alanine via NaNO2/HCl is not mentioned though.

[Edited on 5-2-2007 by Phel]
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[*] posted on 5-2-2007 at 14:21


[A bit off-topic]
On the subject of posting source: they're have been discussion on this forum on the subject of posting source or not and IIRC the conclusion was that posting source was not a bad thing at all and probably don't change anything except maybe making the subject a bit more shady.
Thank you for taking note.
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[*] posted on 5-2-2007 at 14:29


Phel, thanks for sharing this info but isn't this a harder synth than the nitroalkane preparation from NaEtSO4 and NaNO2?

As far as i can recall on this forum there are several nitroalkene threads already on this forum discussing the same issues ...
https://sciencemadness.org/talk/viewthread.php?tid=2995#pid8...

But still the easiest synth seems to be the one above, the only problem is that i have never heard any results from someone trying this reaction, also in chemical abstracts there is little documentation about this synth and some people claim the synth from ca doesnt the supposed job.

Why is NaNO2 a problem?
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[*] posted on 5-2-2007 at 17:28


Quote:
Originally posted by cyberzed
Thanks, not_important for this info ....

So i guess separating such a mixture by forming a bisulfite addition product with the dimethyl ketone is not an option since there will always be something left in the mixture.


No, excess of bisulfite will pull almost all the acetone out. Do a second wash with a lesser amount of bisulfite solution to complete the removal.

Quote:
Another pathway i was thinking of separating this mixture of liquids was by the solubility in dH2O:

acetone solubility: Miscible in all proportions in water
Nitroethane solubility: 4.50 g/100 mL

Wouldnt the acetone mix up with the water, while that one pushes the nitroethane out of the mixture wherafter two layers would be visible?


No, if it were a 50:50 mix adding water will start with leaving a single layer, then as more water is added to layers with all three compounds in each layer.

Distillation with a short fractionation column is still the best bet, followed by washing the nitroethane with a bit of bisulfite solution.

It is possible that they changed the composition of the the product wihout revesing the label and so on. So long as they add nothing new, the MSDS info is OK.

You might try reducing a couple of cc's worth, iron and acid would work, and see if you get any amine formed. You'll smell ethylamine, after a Fe+HCl reduction followed by boiling off the acetone and then adding base. No amine means no nitroethane.
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[*] posted on 5-2-2007 at 17:51


Hello,

It seems to me that yes, acetone can be made into the organosulfite, and yes, it could also be removed as the 2,4-dinitrophenylhydrazide (but, would probably be soluble in nitroethane), but... What about freezing the mix?

Acetone melts at -94.9°C and nitroethane at -50°C. A dry Ice acetone bath could be used (~-77°C) to freeze the nitroethane (if you have any), which could be removed by filtration, etc.

Just a thought,

O3

[Edited on 6-2-2007 by Ozone]




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[*] posted on 5-2-2007 at 20:46


@cyberzed, when we say "Vogel" we mean "Practical Organic Synthesis" by Arthur Vogel, 3rd edition, a DjVu ebook available free from the forum library.

You make a-halopropionic acid from the propionic acid by one of two routes:

1. NBS or NCS

2. Hell-Volhard-Zelinksky with Br2 and a little pyridine catalyst.

Route 1 is more pleasant.

Neutralize the a-haloacid with NaOH and you have the sodium salt.

We have lots of lab manuals like Vogel in the forum library you can download. You will need Adobe Acrobat reader for most and LizardTech DjVu reader for a few. Online there's Organic Syntheses, there's the JACS and JOC etc etc.

Do a forum search and read all the nitroethane threads, download any references they refer to, there won't be any shortage of well documented procedures.

If you can't buy propionic acid you make propionic acid.

If you can't buy N-bromosuccinimide you make it.

If you can't buy bromine you make bromine.

We're chemists, that's what we do. Sometimes getting from A to B requires some effort but it's the sort of effort we enjoy.
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[*] posted on 5-2-2007 at 23:37


cyclohexanone forms the bisulfite addition .. this can then be reacted with piperidine to form 1-piperidinocyclohxane carbonitrile. If this latter product is reacted with ph-mg-Br the result is a vetranary anesthetic with dissociative properties that some folks like ..or did many years ago..:(
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[*] posted on 6-2-2007 at 07:34


As if we didn't know that.

THAT stuff was invented in Detroit by Eli Lilly & Co.

Then tested many years by the US military as a potential incapacitant.

Only later did it become a street drug. It was not what one would consider a good drug. Users often became violent or self destructive. Not recommended, and AFAIK never became popular outside of black ghettos in the US. Or anywhere else in the world.

Once when I was still working in the group lab (before they exiled me to my own lab for working with HCN) one of the profs from the analytical side of the dept came in and said "I've got a detective from the narcotics squad on the phone. He says they have a lab with piperidine, cyclohexanone and bromobenzene. He wants to know what the guy is making." So I told him. That was late 70s. You would have thought the local narcs would have already known, but hey. Interesting that they called the university and not the DEA.
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[*] posted on 6-2-2007 at 07:38


Oh, and by the way, propionic acid is made by oxidizing n-propanol, which is NOT expensive.

Furthermore, back to nitroethane seperation techniques:

Nitroethane is a pseudo-acid and because it is capable to tautomerism, can form water soluble salts in alkiline solutions.

Just a factoid. But you could use it to extract nitroethane with aqueious NaOH from a mixture with a water-immiscible solvent. Upon neutralization most of the nitroethane will seperate since the other tautomer is only partially soluble.

[Edited on 6-2-2007 by Sauron]
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[*] posted on 6-2-2007 at 11:10


Regarding nitroethane containing products: Haven't seen nail polish removers of this kind in Oregon while looking at them in local stores. However "Kilz UpShot Overhead Stain Sealer" did contain small amounts of it, IIRC.
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[*] posted on 6-2-2007 at 21:18


Frankly speaking, unless you happen across a product than is damn near pure nitroethane then it is simply easier to make it.

Ch3Ch2Ch2OH -> Ch3Ch2-Ch2COOH ->Ch3-Ch2Ch(Cl)COOH

-> Ch3Ch2CH(NO2)COOH -> Ch3Ch2NO2 + CO2

Three easy steps from n-propyl alcohol or two from propionic acid.

Sometimes the OTC shit gets in the way of being a chemist.

I mean, chemrox distills something that is supposed to be 50/50 with acetone, only there;s nothing in the post that boils over 90 C. No nitroethane in there, a waste of time.

Then he has a more complex mixture, and there's supposed to be 30-60% nitroethane in there. 60% isn't bad but having to fiddle around with a fractionation to get 30%, in my estimation, sucks. Especially when he wasn't really equipped to do a proper fractionation, so would have to buy a column, lag it, buy a still head, etc etc. And incidentally I think he ran his boilup too fast, or didn't wait for column to equilibrate, or didn't have adequate reflux ratio. Because 6 ml/min seems too high to me for a 100 ml or so pot charge.

For sure his oil bath was hotter than need be. 15 C over the bp is proper, 30 C over is excessive. You don't want the heads to flash off, slowee slowee catchee monkee. Fractionation is not a race, it is tedium punctuated by short periods of action.

All in all, he could make a Kg of the stuff for all that effort and leave the OTC to the tweakers.

[Edited on 7-2-2007 by Sauron]
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[*] posted on 7-2-2007 at 14:02


Misanthropy, thanks for sharing this.

Sauron, couldn't agree more with you, sometimes OTC stuff comes indeed in the way of being a chemist however, given the fact that this is a nitroalkane which is out of most peoples reach and given the fact that the more than 20 different routes which are described in the literature which require hard to procure reagents for most people you can imagine that one wonders how to get a hold of this one.

I did read all the synths described in the literature about this nitroalkane and found only two which particulary drawed my attention, one of them being the one with NaNO2 and NaHEtSO4 and another one was the vapor phase nitriation of propane with propane and HNO3, but the last one would require a dangerous set up and a tube furnace which also isn't that easy to come by.

The most easiest synth one has encountered was the one where someone would start creating Ethyl Hydrogen Sulfate by refluxing ethanol and sulphuric acid, and afterwards neutralizing the excess H2SO4 with CaCO3, wherafter the calcium ethyl sulfate is converted to sodium ethyl sulfate according to following procedure:

To prepare the sodium salt of ethyl hydrogen sulfate, a mixture of alcohol and H2SO4 is boiled under reflux, cooled, and an excess of calcium carbonate is added.
The ethyl hydrogen sulfate is converted into the soluble calcium ethyl sulfate, whilst the excess of H2SO4 is removed as insoluble calcium sulfate.
The aqueous filtrate is then mixed with just sufficient sodium carbonate to give sodium ethyl sulfate, the insoluble calcium carbonate being now filtered off.
The solution of sodium ethyl sulfate can be concentrated on the water-bath without appreciable hydrolysis, and the sulfate finally crystallized out.


• Place 40ml (32g) of rectified spirit in a 250ml round-bottomed flask, and slowly add 16ml (30g) of concentrated sulfuric acid, keeping the liquid in the flask well shaken throughout the addition to ensure thorough mixing.
• Fit a reflux condenser to the flask, and heat the latter on a gauze so that the mixture boils gently for 45 minutes.
• Then cool the product and pour it into 200ml of cold water contained in a large (8-inch) evaporating-basin or in a shallow earthenware dish.
• Now add 23g of finely powdered calcium carbonate with stirring to the acid solution. It is essential to add the calcium carbonate as a fine stream of powder, and to stir the latter immediately into the bulk of the solution: for this purpose, it is best to sift the carbonate through a fine sieve directly into the liquid, or alternatively to add it from a spatula, tapping the latter gently over the liquid to ensure steady addition of the finely powdered chalk. If the carbonate is added carelessly several grams at a time, it becomes rapidly covered with insoluble calcium sulfate, which protects it from further reaction: in these circumstances, at least 10 times the theoretical quantity of the carbonate may be required and the evolution of carbon dioxide may continue for several hours. The addition of the calcium carbonate should take about 30 minutes, and the well-stirred mixture should finally be neutral to litmus-paper.
• Now heat the mixture on a water-bath, using a thermometer as a stirrer, until the temperature reaches 60°C, and then filter at the pump through a wide Buchner funnel: at this temperature, filtration should be rapid.
• Finally wash the residue of calcium sulfate on the filter with a small quantity of hot water, adding the wash-water to the main filtrate.
• In order to convert the calcium ethyl sulfate to sodium ethyl sulfate, add a concentrated aqueous solution of sodium carbonate cautiously drop by drop to the well-stirred filtrate until a drop of the latter withdrawn on a glass rod is just sufficiently alkaline to turn red litmus-paper blue.
• Then filter the solution at the pump, and wash the residual calcium carbonate again with a small quantity of water.
• Evaporate the filtrate on a water-bath until a drop withdrawn on a rod crystallizes on cooling: then allow the solution to stand until almost cold, and finally chill it thoroughly in ice-water. (If the ice-water cooling is omitted, large well-developed colorless crystals of sodium ethyl sulfate will finally separate.) Filter off the crystals at the pump, drain, and dry over calcium chloride in a desiccator.

Yield about 12g. To obtain a second (but necessarily less pure) crop of the sulfate, evaporate the filtrate further on the water-bath, and cool as before.

Once the Sodium Hydrogen Sulfate has been synthed, one could make the desired nitroalkane according to following procedure:

Preparation of Nitroethane
by Gerard Desseigne & Henri Giral

The reaction flask is charged with:
26.5 g (0.0625 * 3moles) of tech grade K2CO3 dissolved in 137 g of water
320 g of 97% tech sodium nitrite
6 ml of cetyl-oleic alcohol or oleic alcoholm(antifoaming agent)
Vol of the mixture is about 420 mls
The mixture is heated on a bath at 130C with stirring. The addition funnel
is charged with 750 ml of an aqueous solution of 444 g (3moles) sodium ethyl
sulfate. The solution is added to the reaction mixture during 50-60 mins at a
suitable rate to keep the reaction mixture at 125-130C, with vigorous
stirring.
The distillation of the nitroethane begins when the addition is started.
When addition of NaEtSO4 is complete 100 mls of water is added during 10 mins.

The distillate separates into 2 layers. Can be distilled at 760mmHg with a distillation column. Distillation starts at 30C. All below 74C is discarded. Temp should settle
at 87C & distillation is stopped at 99.8C.

Yield of nitroethane:96 g (1.28 moles), 42.6% based on NaEtSO4

But i didn't hear anywhere this synth to be actually working?



[Edited on 7-2-07 by cyberzed]
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[*] posted on 7-2-2007 at 16:09


Of course it works, that was somewhat of a test of a 1916 patent. The patent was also tested (no details given, bullshit not called) in JCS 24, 1944, where it was used for their byproduct sodium ethyl sulfate, produced from their ethyl sulfate/Na nitrite nitroethane synthesis. It is interesting that espacenet says that the patent does not exist, yet has his CH75523. I got my copy from the German patent office site.

Attachment: de294755.pdf (206kB)
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[*] posted on 7-2-2007 at 20:04


@cyberzed, kindly tell me what difficult to obtain reagents you are talking about?

n-Propanol?
Your choice of oxidant to propionic acid?
Bromine for a HVZ reaction? You can make your own bromine.
A few drops of pyridine as catalyst
NaNO2

The vapor phase nitration of propane gives a complex mixture requiring seperation, and is not exactly what I would call bench scale amateur chemistry.

If we apply the standard of "easy to get by most people" then very little chemistry will get done. OTC is for lazy meth cooks out to make a fast buck. Often you end up wasting your time trying to isolate a component from a mixture and sometimes as you discovered what you are after isn't even there.

Now, would anyone like to tell me why refluxing H2SO4 and 95% ethanol isn't going to generate diethyl ether? IIRC ethyl hydrogen sulfate is an intermediate in the making of ether. At the very least this side rxn should (a) be a safety problem and (b) reduce the yield of sodium ethyl sulfate.

Furthermore some diethyl sulfate may form and that is a different safety problem because although not as toxic as dimethyl sulfate it is still a potent alkylating agent and a brain carcinogen.

So on all these counts I would only do this in a well ventilated fume hood. The use of an open flame through gauze wire to heat the rxn is clearly obsolete and unsafe.



[Edited on 8-2-2007 by Sauron]
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[*] posted on 7-2-2007 at 20:40


Thank you, Sauron!

OK, I do not have EtNO2; I do have MeNO2. I will mix, 1:1 MeNO2 and Acetone and put it into the SoLo (-77°C freezer). At least I can see if this works (since the Tm for MeNO2 is ~-29°C, I am pretty sure it will). Sure, the solid MeNO2 may be soluble in acetone, but at this temperature, I am relatively confident).

Chillin',

O3

[Edited on 8-2-2007 by Ozone]




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[*] posted on 7-2-2007 at 21:02


Quote:
Originally posted by Sauron


Now, would anyone like to tell me why refluxing H2SO4 and 95% ethanol isn't going to generate diethyl ether? IIRC ethyl hydrogen sulfate is an intermediate in the making of ether. At the very least this side rxn should (a) be a safety problem and (b) reduce the yield of sodium ethyl sulfate.



Looks like roughly twice the molar amount of ethanol as sulfuric acid. Reflux temperature should be less than 100 C, the formation of ether is very slow at those temperatures. That's why most ether preps have you running ethanol into preformed and heated ethyl sulfate + sulfuric acid.

Might make some diethyl sulfate, even more ethanol might be advised.


It has been difficult for me to get n-propanol and sodium nitrite in the past, I ended going through the reduction of nitrate with lead route. Interesting experience, stirring lead wool into a couple of kg of molten sodium nitrate.
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