SYNTHESIS OF ε-CAPROLACTONE
177
purity grade was manufactured by Kuibyshev chemical
factory GUP. Sodium percarbonate (Na2CO3·1.5H2O2)
was purchased as a Persol Super commercial product
(Supinsky chemical factory ZAO) or synthesized by
the patented technique [11]. Magnesium perphthalate
[Mg(OCOC6H4COOOH)2], Dismozon Pur disinfectant
from Bode Chemie GmbH & Co (Germany), was also
synthesized by the method described in [12]. All the in-
organic adducts were analyzed for the content of H2O2
by titration with potassium permanganate [13], and
magnesium monoperphthalate, by titration with sodium
thiosulfate with addition of potassium iodide [13].
and then 0.01 p-toluenesulfonic acid monohydrate was
added to the solution. The mixture was kept at 55°C
for 10 h. The solvent was removed in a rotary vacuum
evaporator with a liquid nitrogen trap (solvent recycling
was 92–93%). A mixture of urea and raw ε-caprolactone
was dissolved in water, and ε-caprolactone was extracted
with chloroform (3 × 8 mL). A combined organic phase
was washed with a saturated sodium chloride solution
and dried with sodium sulfate. After chloroform was
evaporated, the residue was analyzed and, when
necessary, distilled in a vacuum (Table 1).
Oxidation of cyclohexanone by sodium perborate.
A flask was charged with 0.5 g (5.1 mmol) of
cyclohexanone, 5 mL of a solvent, and sodium perborate
(7.65 mmol in terms of H2O2). The mixture was agitated
at 55°C for 4 h. Then, 5 mL of methylene chloride was
added to the reaction mass, the mixture was filtered, and
the filtrate was evaporated and analyzed (Table 2).
To quantitatively estimate the content of reaction
products, we analyzed the reaction mixtures with a
Shimadzu 17A gas chromatograph (Japan) with a flame-
ionization detector (GC-FID), ZB-5 quartz capillary
column (polydimethylsiloxane, 5% phenyl groups,
length 30 m, diameter 0.25 mm, film thickness 0.25
μm); initial column temperature 40°C (holding duration
3 min), heating at a rate of 10 deg min–1 to 300°C
(holding duration 30 min), evaporator temperature
280°C, detector temperature 300°C, carrier-gas nitrogen,
flow division 1 : 30, column flow rate 1.0 mL min–1.
Calculations were made by the internal normalization
over peak areas in the chromatograms.
Oxidation of cyclohexanone by sodium
percarbonate. A flask was charged with 0.5 g (5.1
mmol) of cyclohexanone and 10 mLof the corresponding
acid. Then, the mixture was cooled to 0°C and sodium
percarbonate was added (10.2 mmol in terms of H2O2).
The mixture was agitated at room temperature for 2 h,
diluted with 20 mLf water, and extracted with methylene
chloride (3 × 15 mL). A combined organic phase was
washed with a sodium carbonate solution, dried with
sodium sulfate, evaporated, and analyzed (Table 2).
The products formed were identified with an
Agilent GC 7890A MSD 5975C inert XL EI/CI gas
chromatograph/mass spectrometer (United States) with
a quadrupole mass-spectrometric detector operating
under ionization with 70 eV electrons (GC-MSD), HP5-
MS quartz capillary column (polydimethylsiloxane, 5%
phenyl groups, length 30 m, diameter 0.25 mm, film
thickness 0.25 μm); initial column temperature 40°C
(holding duration 3 min); heating at a rate of 10 deg
min–1 to 290°C (holding duration 30 min); temperature
(°C): evaporator 250, intermediate chamber 280, mass-
spectrometric source 230, quadrupole 250; carrier-gas
helium; flow division 1 : 50; column flow rate 1.0 mL
min–1. Chromatograms were recorded by the full ionic
current, with scanning in the mass range 20–1000 a.m.u.
The identification was based on the mass-spectrum
database NIST05 and analysis of individual substances.
Oxidation of cyclohexanone by magnesium
monoperphthalate. A 0.5-g portion (5.1 mmol) of
cyclohexanone was dissolved in a mixture of 20.4 mL
of water and 20.4 mL methanol, and 0.86 g of sodium
bicarbonate and 2.56 g (6.63 mmol) of magnesium
monoperphthalate was added. The mixture was agitated
at room temperature for 20 h. Then the precipitate
was filtered off and the filtrate was extracted with
methylene chloride (3 × 12 mL). A combined organic
phase was dried with sodium sulfate and evaporated,
and the concentrate was analyzed. The syntheses were
performed by varying the molar ratio between the
ketone and perphthalate (Table 3).
Oxidation of cyclohexanone by sodium
perphthalate (Persol and phthalic anhydride).
Avessel was charged with 6.04 g of ethyl acetate, 0.4 mL
of water, and sodium percarbonate (10.71 mmol in terms
of H2O2). The solution was cooled to 10°C and 1.51 g
(10.2 mmol) of phthalic anhydride was introduced in
portions under vigorous agitation. After that the mixture
A C,H,N analysis was made on a Perkin Elmer
automated analyzer. 13C NMR spectra were recorded
with a Bruker DRX-400 spectrometer.
Oxidation of cyclohexanone by UHP. A flask
was charged with 0.5 g (5.1 mmol) of cyclohexanone,
4.03 mL of a solvent, and 0.62 g (6.6 mmol) of UHP
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 2 2013