Russian Journal of Organic Chemistry, Vol. 41, No. 8, 2005, pp. 1230−1231. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 8,
005, p. 1253.
Original Russian Text Copyright © 2005 by Svetlakov, Nikitin, Nikolaeva.
2
SHORT
COMMUNICATIONS
Octane Oxidation into Carboxylic Acids
N.V. Svetlakov, V.G. Nikitin, and E.A. Nikolaeva
Kazan State Technological University, Kazan, 420015 Russia
Received November 9, 2004
Saturated aliphatic hydrocarbons because of low re-
1.5–2 h till the end of nitrogen oxides evolution and de-
coloration of the reaction mixture. Then the reaction mix-
ture was warmed to 30°C for 2 h and left standing at
activity enter into chemical reactions at elevated tem-
perature and as a rule by radical mechanism [1]. A wide
practical application has found the oxidation of solid and
liquid paraffins into aliphatic alcohols and carboxylic ac-
ids by air oxygen in the presence of catalysts at the tem-
perature over 100°C [2].
20°C for 12 h.Afterwards the reaction mixture was poured
into cold water (400 ml), and the reaction products were
extracted into chloroform (3×100 ml). The extract was
washed with water and dried on Na SO . Chloroform
2
4
We showed formerly [3] that saturated aliphatic hy-
drocarbons at 18–20°C reacted with a mixture of nitric
acid and acetic anhydride furnishing an isomer mixture
of secondary alcohols nitrates. The secondary alcohols
and their derivatives are also known to suffer oxidation
with the nitric acid to monocarboxylic acids with the
cleavage of the hydrocarbon chain [4]. Therefore the
carboxylic acids may be obtained from paraffins via alkyl
nitrates by further decomposition of the latter into acids.
was distilled off, and the obtained acids mixture (20–
2 g) was separated by vacuum distillation.
Valeric acid, bp 58–59°C (9 mm Hg), n 1.3989
2
2
0
D
20
(
publ.: bp 187°C, n 1.409 [5]).Acid number: found 377,
D
–1
calculated 382. IR spectrum, ν, cm : 1720, 2600–3100
1
(COOH). H NMR spectrum, δ, ppm: 0.25 t (3H, CH ),
3
–
0
.5 m (4H, 2CH ), 0.9 t (2H, CH COO ), 5.2 br.s (1H,
2
2
COOH).
2
0
Caproic acid, bp 88-89°C (9 mm Hg), n 1.4180
The octane oxidation to monocarboxylic acids was
performed in two stages: First octan was treated at 18–
D
2
0
(
publ.: bp 202°C, n 1.4145 [5]). Acid number: found
D
–1
2
0°C with a mixture of nitric acid and acetic anhydride
338, calculated 336. IR spectrum, ν, cm : 1720, 2750–
3200 (COOH). H NMR spectrum, δ, ppm: 0.92 t (3H,
CH ), 1.23 m (6H, 3CH ), 2.01 t (2H, CH COO ), 10.05
1
aiming at preparation of alkyl nitrates, and then the tem-
perature was raised to 30°C; therewith the alkyl nitrates
decomposed affording a mixture of monocarboxylic ac-
ids. The acids were extracted with chloroform after di-
luting the reaction mixture with water. We succeeded to
isolate valeric, caproic, and heptanoic acids. The acids of
smaller molecular weight cannot be isolated by this pro-
cedure due to high solubility in water.
–
3
2
2
br.s (1H, COOH).
20
Heptanoic acid, bp 103°C (9 mm Hg), n 1.4233
D
2
0
(
publ.: n 1.4216 [5]). Acid number: found 299, calcu-
lated 300. IR spectrum, ν, cm : 1715, 2720–3100
COOH). H NMR spectrum, δ, ppm: 0.96 t (3H, CH ),
.2 t (2H, CH COO ), 4.4 m (8H, 4CH ), 13.8 s (1H,
D
–
1
1
(
3
3
–
2
2
Taking into account the high electrophilicity of the
reaction medium and low oxidation temperature the
reaction presumably occurs by ionic mechanism. We used
octane of “pure” grade, nitric acid and acetic anhydride
of “technical” grade.
COOH).
Weight ratio of valeric, caproic, and heptanoic caids
was 1:1:3.
IR spectra of carboxylic acids were recorded on
1
a spectrophotometer UR-20. H NMR spectra were reg-
To a mixture of 232 g (3.68 mol) of 98% HNO and
3
9
4 g (0.92 mol) of acetic anhydride at 20°C while vigor-
istered on spectrometer Tesla-497 at operating frequency
100 ΜHz at room temperature from solutions in acetone-
d6, internal reference HMDS.
ous stirring was added dropwise 25 g (0.22 mol) of oc-
tane, and at 18–20°C the reaction mixture was kept for
1070-4280/05/4108-1230©2005 Pleiades Publishing, Inc.