AbstractThe aldol condensation of acetone in solid‐liquid system catalyzed by a family of barium hydroxide catalysts has been carried out. The C‐200 is more active and selective than the commercial barium hydroxide in the aldol condensation of acetone. The structure of the catalysts were analyzed by IR, TGA, TDA and X‐ray powder diagrams. The basic sites of the catalysts were titrated by benzoic acid (BA). The crystalline structure and the number of basic sites are related to the catalytic activity. Ba(OH)2.H2O is shown to be the active com