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: SO
3 is no fun to play around with. BUT: we have people here handling Cl
2, KCN, HgCl
2, DMS and all kinds of really nasty chemicals, wouldn't EtNO
2 be a worthy enough target to try and handle SO
3 ? Both the synth of SO
3 and NaEtSO
4 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 SO
3 could be heating NaHSO
4 or KHSO
4. 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 SO
3 is formed because of the thermal decomposition of the pyrosulfate (those temps seem to be correct for KHSO
4 ??). The reactions are:
1: 2 NaHSO
4 __> Na
2S
2O
7 + H
2O
2: Na
2S
2O
7 ___> Na
2SO
4 + SO
3 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.
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psyloxy--