Zn/Al Layered double hydroxides (LDHs) with various Zn:Al ratios were prepared, characterized by chemical analysis, PXRD, IR, thermal analysis, nitrogen adsorption-desorption and basic sites. The catalytic activity of samples calcified at 450 degrees C for the ketonization of acetic acid was studied in a fixed bed catalytic reactor (10 mm id) with an on-line gas chromatograph. Amongst all, the sample With Zn:Al ratio 3:1 showed the highest surface area (103.5 m(2)/g) and yield of acetone (>89%) with high selectivity.