Author Topic: Nitroethane from Sodium Ethyl Sulfate  (Read 2606 times)

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wolfram

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Nitroethane from Sodium Ethyl Sulfate
« on: October 07, 2003, 09:06:00 PM »

Rhodium

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Waste of space
« Reply #1 on: October 07, 2003, 11:18:00 PM »
First, you have obviously shown that you are capable of linking to documents at my site, so why are you then copying 10-15 kilobytes of irrelevant text from that document anyway? The only section pertinent to your question is the small section below the "Nitroethane from Sodium Ethyl Sulfate" header, not the entire section on how to prepare Sodium Ethyl Sulfate...

Second, to answer your question, I believe that I have read that sodium carbonate works too, but gives a somewhat lowered yield.

psyloxy

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a rant from Mr.Unsatisfied
« Reply #2 on: October 08, 2003, 12:12:00 AM »
Uhm, to add a naive question: why is the use of oleum in sodium ethylsulphate preparation so discouraged around here ? Well, I could answer that question myself in telling me that: SO3 is no fun to play around with. BUT: we have people here handling Cl2, KCN, HgCl2, DMS and all kinds of really nasty chemicals, wouldn't EtNO2 be a worthy enough target to try and handle SO3 ? Both the synth of SO3 and NaEtSO4 with oleum look so damn straight forward and give good yields, that I don't know why everybody avoids it. The opposite is true for the 'state-of-the-art' way IMO, which can be reviewed at:

Post 251119

(Bandil: "Nitroethane ala Antoncho succes", Novel Discourse)
. Now, I know I haven't come up with anything better but this looks like a not-so-much-fun way to get 3mL of nitroethane.

anyway: here are my collected notes concerning SO3 / oleum preparation, surely taken somewhere from Rh.ws and the Hive:

A simple method for SO3 could be heating NaHSO4 or KHSO4. The reaction will be in two stages, one at 200-300°C, when the alkali pyrosulfate is formed, and then the other at 500°C when SO3 is formed because of the thermal decomposition of the pyrosulfate (those temps seem to be correct for KHSO4 ??). The reactions are:

1: 2 NaHSO4 __> Na2S2O7 + H2O

2: Na2S2O7  ___> Na2SO4 + SO3

To produce sulfur trioxide, sodium bisulfate is first dried in a thin layer on a pan in an oven set at 300°F. Let it dry for at least an hour. The sodium bisulfate is then placed in a flask set for distillation. Heat this under a gas flame. The bisulfate will melt and convert to sodium pyrosulfate and water. Try to control the heat to where water is just being produced. Collect the water and discard. When no more water is produced heat the flask more vigorously and the sodium pyrosulfate that was previously formed will decompose into sulfur trioxide and sodium sulfate. Collect this gas in a cooled flask. It will liquify and then solidify if the temperature is low enough. If fuming sulfuric acid is the goal, collect the gas in chilled concentrated sulfuric acid.

--psyloxy--

Vitus_Verdegast

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More suggestions...
« Reply #3 on: October 08, 2003, 04:54:00 AM »
Pyrosulfuric acid, or H2S2O7 corresponds to H2SO4 + SO3, and is in fact oleum containing ~40-45% SO3. It has a melting point of 36°, and is easily prepared by the addition of 2 molar equivalents of sulfuric acid to one mol equiv. of sodium pyrosulfate (Na2S2O7).
Sodium pyrosulfate itself is easily prepared by heating sodium bisulfate above its melting point.

2NaHSO4 __> Na2S2O7 + H2O
Na2S2O7 + 2H2SO4 __> H2S2O7 + 2NaHSO4




Sulfur trioxide can be readily prepared by the oxidation of sulfur dioxide with Caro's acid (permonosulfuric acid).
If potassium persulfate is digested with 40% sulfuric acid in a freezing mixture so that there is no rise in temperature; or if conc. H2SO4 and 5% H2O2 are mixed together, permonosulfuric acid is obtained. The pure acid forms a white crystalline mass which melts at about 45° and is relatively stable.


H2SO4 + H2O2 <__> H2O + H2SO5


The solid acid is best obtained by the action of chlorosulfonic acid on anhydrous hydrogen peroxide  ::) :


ClSO3H + H2O2 <__> HCl + H2SO5


Source: Mellor's Modern Inorganic Chemistry, rev. ed. 1963


wolfram

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Sorry
« Reply #4 on: October 09, 2003, 05:46:00 PM »
I humbly appollogise Grand Master Rhodium for my offence.
:-[  :-[  :-[