Lewis acids immobilized in ionic liquid – application for the acetal synthesis

Catalytic systems composed of metal chloride (InCl3, ScCl3, YCl3, YbCl3, LaCl3, BiCl3, ZnCl3 and CuCl3) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide, [C1C4Pyrr][NTf2] as ionic liquid were prepared. Catalytic activity of all the systems were compared in acetalization reaction between cyclohexanone and triethyl orthoformate. 1,1-Diethoxycyclohexane were formed with high yield and the selectivity at 0°C within 5 minutes. Selected metal chlorides immobilized in ionic liquid were recycled 5 times without a decrease in their activities.