The Synthesis of Cinnamic Acid Catalyzed by Solid Base K_2O/Al_2O_3

Cinnamic acid is synthesized from benzaldehyde and acetic anhydride using solid base K2O/Al2O3 as catalyst.The effect of different reaction condition on the yield has been discussed.The results show that the optimum reaction conditions are as follows:benzaldehyde is 0.05 mol,molar ratio of benzaldehyde to acetic anhydride is 1∶3,the amount of solid base catalyst K2O/Al2O3 is 5.0 g,reaction temperature is 160℃, reaction time is 1 h.The yield of cinnamic acid is 65.4% under the above experimental conditions.The microwave method is superior to dipping method for preparation of solid base catalyst.