CsF supported by alpha- and gamma-alumina was characterized by DTG-DTA coupled with mass spectral analysis of the gases evolved by the solid, XRD, F-19 NMR spectroscopy, and tested in the Michael addition of cyclohexene-2-one with nitroalkanes and in the synthesis of alkyl carbonates. After dehydration at low temperature, F-19 NMR spectroscopy shows that F is in part as CsF when the support is alpha-alumina but only as Cs(3)AIF(6) when the support is gamma-alumina. CsF is detected by XRD on alpha-alumina but not on gamma-alumina. On CsF/alpha-alumina the Michael condensation of 2-cyclohexen-1-one with nitroalkanes can be achieved in a few minutes with an equimolar mixture of reactants. Cs/alpha-alumina is also active after simple drying at 393 K, avoiding the usual activation at higher temperature. It is also surprisingly active for the transesterification of diethylcarbonate by different alcohols and diols with an activity nearly independent of the structure of the substrate. (C) 2004 Elsevier B.V. All rights reserved.