06-06-02 12:07
No 318184
some may remember this promising procedure:
Synlett 2000, 1064
"A Simple and Highly Efficient Procedure for the preparation
of Aliphatic Nitro Compounds Directly from Alcohols"
Baruah, A., Kalita, M., Barua N. C.
and the disproof of this paper Post 294279 (Rhodium: "EtOH/HCl/ACOH/NaNO2 nitroethane method disproven", Chemistry Discourse)
but there is new hope
Patent US3138620 (Patent GB995048),
in example 2 they converted an aliphatic alcohol to the
corresponding nitro compound with NaNO2 and acetic acid.
an elaborate (but unpractical) procedure for the isolation of
the nitro compund from the reaction mixture is given. but on the
second page the say: "alternately ...-nitro-... can be isolated
from the reaction mixture directly by chromatography ..."
for bigger and sensitive molecules chromatography is surely
the way to go. but if nitroethane can be prepared from ethanol
via this procedure, easier separation methods like distillation
should suffice.
the german equivalent Patent DE1188591 names 2 refs
at the end that are not mentioned in the US version.
(Hive Bee)
06-11-02 11:18
No 319775
> ... easier separation methods like distillation should suffice.
REMEMBER(!) that in example 1 of Patent US3138620 they
have prepared with the same reagents the nitrate ester, only
through slightly different reaction conditions than in example 2.
trying to make nitroethane from ethanol with this procedure
can be extremely dangerous and life-threatening !
according to gattermann: "ethyl nitrate(=ethanol nitrate ester
= C2H5NO3) ... decomposes explosively. it belongs in the same
category like nitroglycerine." [1]
furthermore gatterman gives a recipe for the preparation of
ethyl nitrite(=ethanol nitrite ester = C2H5NO2) with: ethanol,
NaNO2 and aq.HCl [2]. with regard to this, treating ethanol
with NaNO2 & acetic acid like in Patent US3138620 can
potentially lead as well to ethyl nitrite(C2H5NO2), that is also
a dangerous stuff(unstable, explosive decomposition possible,
extremely flammable).
YOU HAVE BEEN WARNED !
[1]
"die praxis des organischen chemikers", 1982 43.edition
gattermann, wieland; de gryter: berlin - new york; ISBN 3-11-006654-8
[2]
"die praxis des organischen chemikers", 1962 41.revised edition
gattermann, wieland; walter de gryter & co: berlin