Ce(3+)-Exchanged Montmorillonite (Ce(3+)-Mont) as a Useful Substrate-Selective Acetalization Catalyst

Article abstract of DOI:10.1021/jo00118a021

The acetalization of carbonyl compounds with methanol was investigated in the presence of a cation-exchanged montmorillonite (M(n+)-mont; M(n+) = Ce(3+), Zr(4+), Fe(3+), Al(3+), Zn(2+), H(+) and Na(1+).Ce(3+)-mont was found to be the most effective catalyst for substrate-selective acetalization.Cyclohexanones, benzaldehydes, and acid-sensitive 2-furancarboxaldehyde were converted nearly quantitatively to the corresponding acetals in methanol at 25 deg C in the presence of Ce(3+)-mont.The substrates were activated by a Lewis acidic Ce(3+) cation in the interlayer space on the order of 1 kJ mol^-1 as measured by FT-IR.The turnover number was estimated to be up to 2.6E3 based on the number of active acid sites in Ce(3+)-mont.