The use of tetraalkoxysilanes, particularly tetrakis(perfluoroalkoxy)silanes, in dehydration condensation of carboxylic acids with amines was investigated. Tetrakis(l,I,l,3,3,3-hexafluoro-2-propoxy)silane, Si[OCH(CF3)(2)](4), prepared easily from silicon tetrachloride and sodium 1,1,1,3,3,3-hexafluoro-2-prop-oxide, was found to be an effective dehydrating reagent for preparing various carboxamides in good to high yields from the corresponding carboxylic acids and amines.