4
8
M. G. Abdullaev
separated by filtration, washed with ethanol (20 ml) and
ether (20 ml), and dried in air. Yield, 3.17 g (88% of the the-
oretical value).
G-1000 (5%) on Chromaton. Temperature regime: evapora-
tor, 250°C; column, 200°C. Carrier gas, helium; gas flow
rate, 1.6 liter/h. Sample volume, 0.1 – 0.5 ml; duration of
analysis, 30 – 60 min. Internal standard, tridecane. The cali-
bration coefficients were determined from preliminary analy-
ses of artificial mixtures with preset compositions. The per-
centage content of each component was determined with re-
spect to the internal standard and normalized to the
calibration coefficient.
Preparation
exchanger. A solution of potassium tetrachloropalladate
120.8 mg) in 10 ml of water was poured into a 50-ml flask
of
palladium-containing
anion
(
containing 1 g of the ion exchanger in the OH form in 1 ml
of water. The mixture was stirred with a magnetic stirrer for
1
– 2 h at 20 – 25°C. Then the catalyst was separated by fil-
tration, washed with water (100 ml) and acetone (50 ml), and
dried in air. Palladium content in the catalyst, 3.99 ± 0.01%.
Catalysts with different metal concentrations were obtained
similarly.
Hydrogenation process. An all-glass reactor with ther-
mostat jacket, a magnetic stirrer, and a hydrogen purging fa-
cility was charged with catalyst under a layer of solvent and
the system was activated for 20 – 30 min in a flow of hydro-
gen. Then a weighed amount of the substrate was introduced
in a hydrogen flow and the reaction mixture was intensively
stirred throughout the process at a constant rate of
Catalyst activation. A weighed amount of the catalyst
10 g) was charged into an all-glass temperature-controlled
(
reactor equipped with a stirrer. Upon adjusting the tempera-
ture at 45°C, the reactor was charged with 50 ml of ethanol
and 0.5 g of sodium borohydride. While the mixture was in-
tensively stirred, the reactor was purged with hydrogen for
900 – 1000 rpm and a hydrogen pressure of 98 – 103 kPa
(
(
~ 1 atm). The reaction rate was determined volumetrically
by measuring the hydrogen uptake) and analytically (GC of
6
0 min. Then the catalyst was separated by filtration and
the reaction mixture samples). The kinetic curves were con-
structed with the GC data. The effective reaction rate con-
stants for the catalytic hydrogenation process at low hydro-
gen pressure were calculated with an allowance for the par-
tial pressure of solvent vapors.
washed with water and acetone (50 ml). The ready-to-use ac-
tivated catalyst is kept in acetone.
Determination of palladium in the catalyst. The con-
tent of palladium in a catalyst sample was determined by
measuring the decrease in the concentration of
tetrachloropalladate ions in the course of immobilization on
the carrier. The concentration of tetrachloropalladate ions in
the initial solution was determined spectrophotometrically.
The measurements were performed on a Specord UV-VIS
spectrophotometer at a wavelength of l = 280 nm using 1 cm
quartz cells. The salt concentration in a sample solution was
determined using an optical density calibration plot con-
structed preliminarily for the same wavelength.
REFERENCES
1
2
. USSR State Pharmacopoeia [in Russian], Meditsina, Moscow
1968), Clause 55.
(
. M. G. Abdullaev, A. A. Nasibulin, and M. V. Klyuev, Zh. Org.
Khim., 33, 1759 – 1760 (1997).
3. M. V. Klyuev and M. G. Abdullaev, Izv. Vyssh. Uchebn. Zaved.,
Ser. Khim. Khim. Tekhnol., 42(5), 3 – 13 (1999).
4
5
6
. L. Getterman and G. Vieland, Practicum in Organic Chemistry
[
(
Russian translation], Goskhimizdat, Moscow – Leningrad
1948), pp. 214 – 223.
Analysis and Synthesis
. H. M. Colhown, D. Holton, D. Tompson, and M. Twitt, New Or-
ganic Synthesis Pathways. Practical Use of Transition Metals
Gas chromatography. The hydrogenation products
were analyzed on a Model 3700 chromatograph equipped
with a plasma ionization detector and a glass column
[
Russian translation], Khimiya, Moscow (1989), p. 361.
. USSR State Pharmacopoeia [in Russian], Meditsina, Moscow
(1968), p. 799.
(
2000 ´ 3 mm). The column was filled with Lukopren