Sciencemadness Discussion Board

Prep. of EtNO2 using acetone as solv.

Furch - 20-3-2007 at 13:00

I wonder if the standard solvents for the preparation of nitroethane from ethyl bromide and NaNO2 can be swapped for other Sn2 facilitating solvents, such as acetone. The reason is that acetone for most people is much cheaper and more readily available than DMSO and DMF and formamide.

Since the reaction in question takes place at room temperature, the low boiling point of acetone can hardly be a reason for it not to work.

I know acetone isn't AS good a Sn2 promoting solvent as DMF and DMSO and formamide, but perhaps it's worth the compromise?

What am I missing?

guy - 20-3-2007 at 13:01

The problem is that acetone doesn't dissolve ionic salts like NaNO2 well. DMF and DSMO are very polar and can dissolve those compounds.

Furch - 20-3-2007 at 13:46

Sure, my common sense tells me that as well... But I also understand that for instance NaI in acetone reacts readily with other alkylhalides... This wouldn't be possible unless the I- dissolves to some extent in the acetone. So reasonably it should have some solvative effect on inorganic salts, no?

guy - 20-3-2007 at 17:33

Then I guess in the cases where it does dissolve and doesn't react with the acetone it should work.

jon - 20-3-2007 at 20:19

yeah there was some procedure where hypothetically it was done in DMSO but ethyl bromide would make a sulfur ylide with dmso so we know that's bullshit.

chemrox - 4-4-2007 at 22:45

Jon, if the ethyl bromide is distilled from DMSO the product will be acetaldehyde...there's a paper on this I shall find and send you or post if requested.

Nicodem - 4-4-2007 at 23:28

Quote:
Originally posted by Furch
Sure, my common sense tells me that as well... But I also understand that for instance NaI in acetone reacts readily with other alkylhalides... This wouldn't be possible unless the I- dissolves to some extent in the acetone. So reasonably it should have some solvative effect on inorganic salts, no?

But NaNO2 (unlike NaI) is insoluble in acetone, at least as far as I know.