A comparative study on basicity of supported K-salt catalysts has been carried out for the preparation of trans-anethole [1-methoxy-4-(1-propen-1-yl) benzene]. It is observed that strong basic sites facilitated 99% conversion of methyl chavicol [1-methoxy-4-(2-propen-1-yl) benzene] with 89% selectivity of trans-anethole. Activation energy for isomerization of methyl chavicol was found to be in the range of 5.65 -8.67 kJ/mol using 25% K(2)CO(3) loaded on alumina. The catalysts were characterized by CO(2)-TPD and BET surface area.