Nitroalkane salts

[PolytheneSam]

-->Novelty:  Can nitroalkanes be purified via their salts?

This seems to say that its possible to make nitroalkane salts.  Making nitroalkane salts might provide a way to purify nitroalkanes.  Note that nitromethane salts are sparingly soluble in alcohol (EtOH?) and MeOH.

CA4:925

Molecular Refraction of Isomerizable and of Unsaturated Acids and of Their Salts.
A. HANTZSCH AND K. MEISENBURG. Ber., 43, 95-105.--The mol. refraction of nitromethane salts could not be determined, on account of their sparing solubility in alc. and in MeOH and because of their instability.  Unless otherwise stated, the determination mentioned below were made in alc.  The figures refer to the mol. refraction of the various compounds for the (D) lines.  Nitroethane, 16-83; K salt, 17.85.  Nitropentane, 30.57; K salt, 32.15.  These results confirm Brühl's conclusion that in the case of aliphatic compounds the solvent has practically no effct on the mol. refraction and they show also that the salts possess a constitution different from that of the parent substance.  p-Bromophenol, 36.67; Na salt, 37.45. p-Chlorophenol,33.42; Na salt, 34.28.  It is uncertain whether the differences between these phenols and their.........

The rest of the abstract discusses phenols and isn't related to nitroalkanes.

[starlight]

metal salts of nitroalkanes are sensitive to both impact and heat and are liable to explosive decomposition. I would not be keen on isolating solid salts.

[PolytheneSam]

What if they were kept wet and then decomposed after being isolated?

[lugh]

Hantzsch and Shultze published their research in purifying nitronic acida and nitroalkanes via the alkali metal salts in Ber 29 699 (1896)    Many nitronate salts are shock senstitive explosives, and are particularly hazardous when anhydrous, so thorough research into the techniques employed is advisable  

[Antoncho]

... but nitroalkane salts, apart from being explosive, also tend to partially decompose into aldehydes(ketones) and NO2 upon acidification.

If one is to add acid into the salt's solution slowly, then up to 85% yield can bee achieved (IIRC - can't remember, read somewhere on The Hive); if you add salt into xcess acid, the carbonyl cpd is the main product and this is generally known as Nef reaction



Antoncho


P.S. Please, forgive me for being off-topic, but , MAYBEE, someone can think of any other method that can bee used to free nitroethane from - specifically - ethyl nitrite impurity? Beelive me, bees, this is of a very practical and very immediate imporatnce to SWIM!

[lugh]

Phlorglucinol and resorcinol are used as nitrite scavengers during nitroalkane synthesis, phlorglucinol is the more effective nitrite scavenger