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Russian Journal of Applied Chemistry, Vol. 75, No. 3, 2002, pp. 511!512. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 3,
2002, pp. 522!523.
Original Russian Text Copyright + 2002 by Osadchenko, Tomilov.
Phase-Transfer Catalysis in Synthesis of Oximes
I. M. Osadchenko and A. P. Tomilov
State Research Institute of Organic Chemistry and Technology, Moscow, Russia
Received September 25, 2001
Abstract-Perfluorinated higher carboxylic acids were tested as phase-transfer catalysts in synthesis of
The known synthetic routes to oximes are based
on reaction of a carbonyl compound with an aqueous
solution of a hydroxylamine salt  in the presence
of inorganic compounds, e.g., of NaOH:
OH. HX + NaOH 6 RCR` +H
O + NaX,
where R = Alk; R` = Alk, H, Ar, Ht; X is an inorganic
Because carbonyl compounds, as a rule, are poorly
soluble in water, the reaction is usually performed in
aqueous alcohol. However, the reaction is slow (53
8 h) and does not go to completion even in the pres-
ence of excess hydroxylamine salt. The yield of the
oxime based on the taken carbonyl compound usually
does not exceed 80%.
To promote the reaction, various phase-transfer
catalysts were tested without using an organic solvent.
We found that the most effective phase-transfer cata-
lysts for oximation are higher perfluorinated car-
boxylic acids exhibiting a high surface activity. Addi-
tion of these compounds (0.0730.10 wt %) appreciab-
ly shortens the reaction time and allows preparation of
oximes in high, sometimes almost quantitative yields.
This can be illustrated by several examples.
Acetophenone oxime. (a) A 1-l reaction vessel
equipped with a thermometer, a reflux condenser,
a stirrer, and a dropping funnel was charged with
a solution of 76.5 g (1.1 mol) of hydroxylamine hy-
drochloride in 200 ml of water and 120 g (1.0 mol) of
acetophenone, and a 20% solution of 44 g (1.1 mol)
of NaOH was added dropwise with stirring at 36oC
until pH 738 was attained. The mixture was heated at
60370oC for 5 h and then cooled to 033oC. The re-
sulting crystalline precipitate was filtered off, washed
with several portions of ice-cold water, and dried in
a desiccator over CaCl
to constant weight; 100 g of
acetophenone oxime was obtained, mp 57oC (pub-
lished data [2, 3]: 57358oC); yield 70%.
(b) The reaction was performed similarly to pro-
cedure (a) but in the presence of 0.61 g (1.7 mmol) of
perfluoroenanthic acid with addition of a 20% NaOH
solution at 60370oC; the mixture was heated at this
temperature for 3.5 h. Yield of acetophenone oxime
131.6 g (98%).
(c) The reaction was performed similarly to pro-
cedure (a) but in the presence of 0.61 g (2.3 mmol) of
perfluorovaleric acid; time of heating at 60370oC3h.
Yield of acetophenone oxime 132.3 g (99%).
5-Methyl-3-hexanone oxime. A reaction vessel
[the same as in procedure (a)] was charged with 57 g
(0.8 mol) of 5-methyl-3-hexanone, 39 g (0.56 mol) of
hydroxylamine hydrochloride, 100 ml of water, and
0.6 g (1.65 mmol) of perfluoroenanthic acid; 100 ml
of 25% aqueous NaOH was added, keeping the tem-
perature below 35oC, after which the mixture was
heated to 67368oC and kept at this temperature for
3 h. After cooling, the upper layer was separated,
washed with three 20-ml portions of cold water, and
distilled in a vacuum (10312 mm Hg). A fraction
boiling at 85395oC was collected. Yield of 5-methyl-
3-hexanone oxime 49.7 g (71%); n
lished data : n
Salicylaldoxime. Similarly to procedure (a), a
500-ml reactor was charged with 26 g (0.21 mol) of
salicylaldehyde, 16 g (0.21 mol) of hydroxylamine
hydrochloride, 40 ml of water, and 0.2 g (0.55 mol) of
perfluoroenanthic acid; a solution of 9 g (0.225 mol)
of NaOH in 30 ml of water was slowly added, after
which the mixture was heated to 65370oC and kept at
this temperature for 3 h. After cooling to 5310oC, the
mixture was worked up similarly to procedure (a).