Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Purification of ethylsulfuric acid?
mnick12
Hazard to Others
***




Posts: 404
Registered: 30-12-2009
Location: In the lab w/ Dr. Evil
Member Is Offline

Mood: devious

[*] posted on 1-12-2010 at 18:00
Purification of ethylsulfuric acid?


So I have about 60ml of ethylsulfuric acid that I made by refluxing anhydrous sodium bisulfate with denatured alcohol. After refluxing I cooled and vac filtered the acid from the sodium sulfate, I then rinsed the sodium sulfate with ethanol to try and remove any acid that remained behind. Now I have about 60ml of a thick oil that has a slight yellowish color. Now my question is what would be the best way to remove the ethanol without decomposing the ethylsulfuric acid? Would stripping the ethanol under vacuum work? If possible I would like to avoid the formation of diethylsulfate.

Thanks!
View user's profile View All Posts By User
sabbath06
Harmless
*




Posts: 10
Registered: 17-8-2010
Member Is Offline

Mood: No Mood

[*] posted on 25-1-2011 at 06:16


Ethyl hydrogen sulfate boils at 209 degrees C while ethanol boils at 78 degrees C so simple distillation seems like it would be the way to go

but I could be wrong!
View user's profile View All Posts By User
Nicodem
Super Moderator
*******




Posts: 4230
Registered: 28-12-2004
Member Is Offline

Mood: No Mood

[*] posted on 25-1-2011 at 11:31


Quote: Originally posted by sabbath06  
Ethyl hydrogen sulfate boils at 209 degrees C
...
but I could be wrong!

Are you sure? Where did you got that info from? At which pressure?
I would expect it to decompose at considerably lower temperatures and even if not, that temperature is simply too low for a compound like that at 1 atm pressure.
View user's profile View All Posts By User
turd
National Hazard
****




Posts: 800
Registered: 5-3-2006
Member Is Offline

Mood: No Mood

[*] posted on 25-1-2011 at 11:58


Quote: Originally posted by Nicodem  
Where did you got that info from?

Probably Wikipedia (http://en.wikipedia.org/wiki/Ethyl_sulfate) and it clearly states that 209°C is the decomposition point. Apparently some people are not aware of the meaning of the "(decomp.)" notation for melting and boiling points.
View user's profile View All Posts By User
Nicodem
Super Moderator
*******




Posts: 4230
Registered: 28-12-2004
Member Is Offline

Mood: No Mood

[*] posted on 26-1-2011 at 06:23


Wikipedia! What a surprise. How come people so easily gave up on verifying references and trust Wikipedia so lightly?

SciFinder gives no info about the boiling point. The only physical data it gives is the density (1.3657 g/cm3 at 20 °C). Though one of the papers describing the synthesis of ethyl sulfuric acid says it starts decomposing as low as 125 °C:
Quote:
Huaxue Shiji, 13 (1991) 190. CA 115: 158460
Abstract: Stirring 95% EtOH (excess) with concd. H2SO4 in the presence of Na2SO4 at 25 gave 98.8% EtOSO3H which was heated at 125-140 under reduced pressure to give 87.2% Et2SO4.
View user's profile View All Posts By User
ThatchemistKid
Hazard to Others
***




Posts: 132
Registered: 2-6-2010
Member Is Offline


[*] posted on 30-1-2011 at 19:43


Heating ethyl sulfuric acid with ethanol should yield ether as that is the intermediate in the general over the counter diethyl ether synthesis.
View user's profile View All Posts By User

  Go To Top