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Author: Subject: Sodium Ethyl Sulfate
Wolfram
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[*] posted on 19-11-2003 at 04:47
Sodium Ethyl Sulfate


From http://www.rhodium.ws/chemistry/nitroalkane.html

Two moles of absolute ethanol (92 grams) is slowly dripped into a beaker containing one mole of 20% Oleum (H2SO4 containing 20% SO3), adjusting the rate so that the temperature is maintained at 45°C. When all the ethanol is added, the solution is neutralized with anhydrous sodium carbonate (Na2CO3), care being taken for the evolution of carbon dioxide. Yield 85% of theory.

Q1. Whould the yeld really drop to 0 if I tried with 96% H2SO4 insead. Making Oleum seems little dangerous.

Q2 Could 95% etOH be considered absolute ethanol or should it be dehydrated with CaCl maybee..?
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[*] posted on 19-11-2003 at 06:21


Add 96% H2SO4 to your ethanol, this binds the water but dilutes the H2SO4.

The next step is bubbling SO3 (by decomposition of CuSO4 or else) through the solution ethanol/H2SO4. This will concentrate your H2SO4, thereby consuming water AND making oleum if you add enough SO3.

Working with SO3 always involves certain hard to control hazards. I would avoid glassware for the SO3 production.




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thumbup.gif posted on 19-11-2003 at 07:33


"SO3 (by decomposition of CuSO4 or else)"
HUH? It takes a temperature over a thousand degrees to decompose CaSO4! There's a thread on oleum in this section that lists much easier preparation methods.
"I would avoid glassware for the SO3 production."
Why? I always considered glass the most chemically stable entity available to a home chemist. You mean that SO3 could displace the silicate ion andthe outer layer would turn into sulfates? But that would happen only with a vey thin outer layer.
I think the yield wouldn't drop to 0 if you used concentrated sulfuric acid (let it be CSA from now on) instead of oleum if you use it in excess. With a large excess the yield would still be high (maybe the reaction would be slower).
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[*] posted on 20-11-2003 at 13:58


Any water present will destroy the product. The equilibrium vastly favours acid and alcohol over ester and water.
You can't dry alcohol over CaCl2, it forms a complex (and dissolves).
Glass is innert but it's fragile.
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[*] posted on 19-11-2005 at 06:33


This is an old one to drag up...

But, what would happen if you used sodium pyrosulfate in the acid instead of oleum?

For that matter, why couldn't you use straight sodium pyrosulfate minus the acid?
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[*] posted on 19-11-2005 at 16:12
Better Way?


US3024263 Process for the Preparation of Anhydrous Ethyl Sulfuric Acid

2NaHSO4+EtOH=EtHSO4+Na2SO4+H20

Very simple and the hydrate of the sodium sulfate removes the water preventing hydrolysis.

Anyone ever try this procedure? I'm about to and was looking for input from those with experience.

Patent claims 96% EtOH, bisulfate monohydrate and concentrated or less sulfuric acid may be used!
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[*] posted on 19-11-2005 at 16:49


That, my son, is a gem.
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[*] posted on 19-11-2005 at 16:57


That ain't a gem, thats... well almost as good as a butt naked redhead spreadeagled on the bed waitin for ya.
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[*] posted on 22-11-2005 at 03:53


Usually HEtSO4 is made by mixing 95% H2SO4 with a 30% molar xcess of CuSO4-dehydrated EtOH and 3x xcess (counting on decahydrate, i.e. 0,3 moles per 1 mole of acid) finely ground Na2SO4.

Apply no cooling while adding, let chill at RT to ~40 C, than shake under a stream of cold water beelow 20 C. Let stand for several hrs with occasional shaking.

Titrate by dripping a weighed sample into dil. aq. NaOH until neutral pH (HEtSO4 takes 1 eq. NaOH, unreacted sulfuric - 2 eq's).

Usually gave me a quantative yield.
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[*] posted on 24-11-2005 at 20:20
Aqueous Method


Hey Antoncho perhaps you could elaborate on some ideas you presented long ago in another forum which I happened to save a copy of.

Did you ever develop this as it seems it would have definite advantages over the dry or wet method!

".....but i always wondered if one could improve the yield (maybee dramatically so) by taking advantage of the following gimmicks:

a) To your mixed NaNO2/NaEtSO4 add some EtOH and reflux for some time. Both reagents are slightly soluble in EtOH, so they will probably inter diffuse, thus providing a much larger rxn surface. Then EtOH is just distilled off.

b) Use microwave for (at least - even if the 'microwave effect' will bee of no use here) even and smooth heating. It's been SWIM's practice that someof his nitroalkane (MeNO2, in his case) decomposes/reacts from overheating somewhat on the falsk's walls........"

The dry method which was tried years ago only once by me didn't work out so well due to the scorching/heat transfer problem. Soon after I found a source of the ready made stuff. This was in the days before it was Listed.

Following is an excerpt from the French article translated by somebee which you may be familiar with.

PROCEDURE from the French

"...... One introduces into reaction flask:
137 g of water;
26.5 g (0.0625 X 3 moles) of technical 98% potassium carbonate.
One agitates to ensure dissolution, then adds: 320 g (4.5 moles) of technical 97% sodium nitrite;
6 ml of oleic alcohol, or cétyl-oleic alcohol (antifoaming agents).
Volume charged = 420 ml approximately.

One heats to 130° C, with the glycerin bath, while agitating.

Into the addition funnel, one places a quantity of sodium ethyl sulphate solution containing 444 g (3 moles);
Approximate volume: 750 ml.
Duration of addition 50 to 60 minutes.

The rate of addition is regulated so that the temperature of the mass in reaction remains within the limits indicated: 125 with 130° C. ................."

Any ideas or comments?? regarding this versus Antonchos ethanol solvent idea?
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[*] posted on 25-11-2005 at 08:13


If you are going to consider EtOH as the solvent you will need to reflux if you use microwaves because of the volatility of the solvent. You will need an oven modified for reflux.
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[*] posted on 25-11-2005 at 12:52


I think that the microwaving would really not promote even heating unless it was specially modified with a stirrer and true variable infinite type power control. The somewhat new inverter type micros could do this with a little tweaking for a temp sensor in a closed loop feedback circuit.

Simpler would be to immerse the flask all the way to the neck and lag the takeoff short adaptor. Maybe heat tape under it as well.

Problem is that the bath temp must be too high if only partially immersed and this causes the scorching. It also helps to distill
quicky to minimize any decomposition.
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[*] posted on 3-12-2011 at 10:49


Quote: Originally posted by Wolfram  


When all the ethanol is added, the solution is neutralized with anhydrous sodium carbonate (Na2CO3), care being taken for the evolution of carbon dioxide. Yield 85% of theory.



Once I have anhydrous ethyl sulfate I naturalize it with anhydrous sodium carbonate to get the sodium salt. No byproducts are formed besides carbon dioxide so what I can expect is a moist clumpy mass of sodium ethyl sulfate that will be contaminated with ethyl sulfate and sodium carbonate. I want to use a solvent to help the reaction proceed once the sodium salt begins to clump up. Ethanol will probably work. I can recrystallize from ethanol to purify.

Has anyone attempted this? What can I expect?



[Edited on 4-12-2011 by cipi]
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