1998
SASHINA et al.
reaction mixture was stirred at a temperature of 110–
130°C for 24–48 h with reflux without nitrogen flow.
Upon completion, the reaction product obtained
separated in layers, toluene was decanted from the
dense layer of ionic liquid. The product was washed
with toluene. Recrystallization was carried out by
dissolution in acetonitrile followed by precipitation
with excess diethyl ether. Volatile organic compounds
were removed on a rotary evaporator (Rotavapor R-
215, Büchi, Switzerland) for 6–8 h, the pressure
gradually was reduced from atmospheric to 20–
120 mbar, and the temperature was raised from 60°C
to 90–140°C.
ACKNOWLEDGMENTS
This work was financially supported by the Ministry
of Education and Science of the Russian Federation.
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 82 No. 12 2012